diff --git a/.github/workflows/verify-linux.yml b/.github/workflows/verify-linux.yml
index 4c2817f4ee..2d7bb6446e 100644
--- a/.github/workflows/verify-linux.yml
+++ b/.github/workflows/verify-linux.yml
@@ -14,8 +14,6 @@ jobs:
 
     steps:
     - uses: actions/checkout@v4
-      with:
-        submodules: recursive
 
     - name: Check white space (non-blocking)
       run: |
@@ -50,13 +48,14 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
-        with:
-          submodules: recursive
 
       - uses: ./.github/actions/ubuntu-setup/
 
-      - name: Compile FMS
-        run: make -C .testing -j build/deps/lib/libFMS.a
+      - name: Compile dependencies
+        run: |
+          make -C .testing -j build/deps/lib/libFMS.a
+          make -C .testing -j PKG= build/deps/lib/libgsw.a
+          make -C .testing -j PKG= build/deps/lib/libcvmix.a
 
       - name: Compile MOM6 with symmetric indexing
         run: make -C .testing -j build/symmetric/MOM6
@@ -75,13 +74,14 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
-        with:
-          submodules: recursive
 
       - uses: ./.github/actions/ubuntu-setup/
 
-      - name: Compile FMS
-        run: make -C .testing -j build/deps/lib/libFMS.a
+      - name: Compile dependencies
+        run: |
+          make -C .testing -j build/deps/lib/libFMS.a
+          make -C .testing -j PKG= build/deps/lib/libgsw.a
+          make -C .testing -j PKG= build/deps/lib/libcvmix.a
 
       - name: Compile MOM6 with asymmetric indexing
         run: make -C .testing -j build/asymmetric/MOM6
@@ -100,13 +100,14 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
-        with:
-          submodules: recursive
 
       - uses: ./.github/actions/ubuntu-setup/
 
-      - name: Compile FMS
-        run: make -C .testing -j build/deps/lib/libFMS.a
+      - name: Compile dependencies
+        run: |
+          make -C .testing -j build/deps/lib/libFMS.a
+          make -C .testing -j PKG= build/deps/lib/libgsw.a
+          make -C .testing -j PKG= build/deps/lib/libcvmix.a
 
       - name: Compile MOM6 with bit-reproducible optimization
         run: make -C .testing -j build/repro/MOM6
@@ -125,13 +126,14 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
-        with:
-          submodules: recursive
 
       - uses: ./.github/actions/ubuntu-setup/
 
-      - name: Compile FMS
-        run: make -C .testing -j build/deps/lib/libFMS.a
+      - name: Compile dependencies
+        run: |
+          make -C .testing -j build/deps/lib/libFMS.a
+          make -C .testing -j PKG= build/deps/lib/libgsw.a
+          make -C .testing -j PKG= build/deps/lib/libcvmix.a
 
       - name: Compile MOM6 supporting OpenMP
         run: make -C .testing -j build/openmp/MOM6
@@ -151,12 +153,10 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
-        with:
-          submodules: recursive
 
       - uses: ./.github/actions/ubuntu-setup/
 
-      - name: Compile target FMS
+      - name: Compile target depedencies
         run: |
           make -C .testing \
           DO_REGRESSION_TESTS=1 \
@@ -184,13 +184,14 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
-        with:
-          submodules: recursive
 
       - uses: ./.github/actions/ubuntu-setup/
 
-      - name: Compile FMS
-        run: make -C .testing -j build/deps/lib/libFMS.a
+      - name: Compile dependencies
+        run: |
+          make -C .testing -j build/deps/lib/libFMS.a
+          make -C .testing -j PKG= build/deps/lib/libgsw.a
+          make -C .testing -j PKG= build/deps/lib/libcvmix.a
 
       - name: Compile MOM6 with aggressive optimization
         run: make -C .testing -j build/opt/MOM6
@@ -217,12 +218,10 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
-        with:
-          submodules: recursive
 
       - uses: ./.github/actions/ubuntu-setup/
 
-      - name: Compile target FMS
+      - name: Compile target dependencies
         run: |
           make -C .testing \
           DO_REGRESSION_TESTS=1 \
@@ -260,13 +259,14 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
-        with:
-          submodules: recursive
 
       - uses: ./.github/actions/ubuntu-setup/
 
-      - name: Compile FMS
-        run: make -C .testing -j build/deps/lib/libFMS.a
+      - name: Compile dependencies
+        run: |
+          make -C .testing -j build/deps/lib/libFMS.a
+          make -C .testing -j PKG= build/deps/lib/libgsw.a
+          make -C .testing -j PKG= build/deps/lib/libcvmix.a
 
       - name: Compile MOM6 with code coverage
         run: make -C .testing -j build/cov/MOM6
@@ -296,13 +296,14 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
-        with:
-          submodules: recursive
 
       - uses: ./.github/actions/ubuntu-setup/
 
-      - name: Compile FMS
-        run: make -C .testing -j build/deps/lib/libFMS.a
+      - name: Compile dependencies
+        run: |
+          make -C .testing -j build/deps/lib/libFMS.a
+          make -C .testing -j PKG= build/deps/lib/libgsw.a
+          make -C .testing -j PKG= build/deps/lib/libcvmix.a
 
       - name: Compile MOM6 for the GFDL coupled driver
         run: make -C .testing -j check_mom6_api_coupled
@@ -317,8 +318,6 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
-        with:
-          submodules: recursive
 
       - uses: ./.github/actions/ubuntu-setup
 
@@ -350,8 +349,6 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
-        with:
-          submodules: recursive
 
       - uses: ./.github/actions/ubuntu-setup
 
@@ -375,8 +372,6 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
-        with:
-          submodules: recursive
 
       - uses: ./.github/actions/ubuntu-setup
 
@@ -400,8 +395,6 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
-        with:
-          submodules: recursive
 
       - uses: ./.github/actions/ubuntu-setup
 
@@ -425,8 +418,6 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
-        with:
-          submodules: recursive
 
       - uses: ./.github/actions/ubuntu-setup
 
@@ -460,8 +451,6 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
-        with:
-          submodules: recursive
 
       - uses: ./.github/actions/ubuntu-setup
 
@@ -487,8 +476,6 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
-        with:
-          submodules: recursive
 
       - uses: ./.github/actions/ubuntu-setup
 
@@ -522,8 +509,6 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
-        with:
-          submodules: recursive
 
       - uses: ./.github/actions/ubuntu-setup
 
@@ -558,8 +543,6 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
-        with:
-          submodules: recursive
 
       - uses: ./.github/actions/ubuntu-setup
 
@@ -592,8 +575,6 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
-        with:
-          submodules: recursive
 
       - uses: ./.github/actions/ubuntu-setup
 
@@ -638,8 +619,6 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
-        with:
-          submodules: recursive
 
       - uses: ./.github/actions/ubuntu-setup
 
@@ -670,8 +649,6 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
-        with:
-          submodules: recursive
 
       - uses: ./.github/actions/ubuntu-setup
 
diff --git a/.github/workflows/verify-macos.yml b/.github/workflows/verify-macos.yml
index d058336053..e58e824dde 100644
--- a/.github/workflows/verify-macos.yml
+++ b/.github/workflows/verify-macos.yml
@@ -16,13 +16,14 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
-        with:
-          submodules: recursive
 
       - uses: ./.github/actions/macos-setup/
 
-      - name: Compile FMS
-        run: make -C .testing -j build/deps/lib/libFMS.a
+      - name: Compile dependencies
+        run: |
+          make -C .testing -j build/deps/lib/libFMS.a
+          make -C .testing -j PKG= build/deps/lib/libgsw.a
+          make -C .testing -j PKG= build/deps/lib/libcvmix.a
 
       - name: Compile MOM6 with symmetric indexing
         run: make -C .testing -j build/symmetric/MOM6
@@ -41,13 +42,14 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
-        with:
-          submodules: recursive
 
       - uses: ./.github/actions/macos-setup/
 
-      - name: Compile FMS
-        run: make -C .testing -j build/deps/lib/libFMS.a
+      - name: Compile dependencies
+        run: |
+          make -C .testing -j build/deps/lib/libFMS.a
+          make -C .testing -j PKG= build/deps/lib/libgsw.a
+          make -C .testing -j PKG= build/deps/lib/libcvmix.a
 
       - name: Compile MOM6 with asymmetric indexing
         run: make -C .testing -j build/asymmetric/MOM6
@@ -66,13 +68,14 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
-        with:
-          submodules: recursive
 
       - uses: ./.github/actions/macos-setup/
 
-      - name: Compile FMS
-        run: make -C .testing -j build/deps/lib/libFMS.a
+      - name: Compile dependencies
+        run: |
+          make -C .testing -j build/deps/lib/libFMS.a
+          make -C .testing -j PKG= build/deps/lib/libgsw.a
+          make -C .testing -j PKG= build/deps/lib/libcvmix.a
 
       - name: Compile MOM6 with bit-reproducible optimization
         run: make -C .testing -j build/repro/MOM6
@@ -91,13 +94,14 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
-        with:
-          submodules: recursive
 
       - uses: ./.github/actions/macos-setup/
 
-      - name: Compile FMS
-        run: make -C .testing -j build/deps/lib/libFMS.a
+      - name: Compile dependencies
+        run: |
+          make -C .testing -j build/deps/lib/libFMS.a
+          make -C .testing -j PKG= build/deps/lib/libgsw.a
+          make -C .testing -j PKG= build/deps/lib/libcvmix.a
 
       - name: Compile MOM6 supporting OpenMP
         run: make -C .testing -j build/openmp/MOM6
@@ -117,12 +121,10 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
-        with:
-          submodules: recursive
 
       - uses: ./.github/actions/macos-setup/
 
-      - name: Compile target FMS
+      - name: Compile target dependencies
         run: |
           make -C .testing \
           DO_REGRESSION_TESTS=1 \
@@ -155,8 +157,6 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
-        with:
-          submodules: recursive
 
       - uses: ./.github/actions/macos-setup
 
@@ -188,8 +188,6 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
-        with:
-          submodules: recursive
 
       - uses: ./.github/actions/macos-setup
 
@@ -213,8 +211,6 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
-        with:
-          submodules: recursive
 
       - uses: ./.github/actions/macos-setup
 
@@ -238,8 +234,6 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
-        with:
-          submodules: recursive
 
       - uses: ./.github/actions/macos-setup
 
@@ -263,8 +257,6 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
-        with:
-          submodules: recursive
 
       - uses: ./.github/actions/macos-setup
 
@@ -298,8 +290,6 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
-        with:
-          submodules: recursive
 
       - uses: ./.github/actions/macos-setup
 
@@ -325,8 +315,6 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
-        with:
-          submodules: recursive
 
       - uses: ./.github/actions/macos-setup
 
@@ -360,8 +348,6 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
-        with:
-          submodules: recursive
 
       - uses: ./.github/actions/macos-setup
 
@@ -396,8 +382,6 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
-        with:
-          submodules: recursive
 
       - uses: ./.github/actions/macos-setup
 
diff --git a/.gitignore b/.gitignore
index c57b950fc2..d246027b44 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,23 +1,2 @@
-# Ignore vim and emacs files
-*.swp
-*~
-html
-
-
 # Build output
-*.o
-*.mod
-MOM6
 build/
-deps/
-pkg/MARBL
-
-
-# Autoconf output
-aclocal.m4
-autom4te.cache/
-config.log
-config.status
-configure
-/Makefile
-Makefile.mkmf
diff --git a/.gitlab/pipeline-ci-tool.sh b/.gitlab/pipeline-ci-tool.sh
index d948b72008..194794c202 100755
--- a/.gitlab/pipeline-ci-tool.sh
+++ b/.gitlab/pipeline-ci-tool.sh
@@ -161,7 +161,14 @@ nolibs-ocean-ice-compile () {
     mkdir -p build-ocean-ice-nolibs-$1
     cd build-ocean-ice-nolibs-$1
     make -f ../tools/MRS/Makefile.build ./$1/env BUILD=. ENVIRON=../../environ -s
-    ../src/mkmf/bin/list_paths -l ../src/MOM6/config_src/{drivers/FMS_cap,memory/dynamic_symmetric,infra/FMS1,ext*} ../src/MOM6/src ../src/SIS2/*src ../src/icebergs/src ../src/{FMS1,coupler,ice_param,land_null,atmos_null}
+    ../src/mkmf/bin/list_paths -l \
+      ../src/MOM6/config_src/{drivers/FMS_cap,memory/dynamic_symmetric,infra/FMS1,ext*} \
+      ../src/MOM6/src \
+      ../src/SIS2/src \
+      ../src/SIS2/config_src/dynamic_symmetric \
+      ../src/SIS2/config_src/external/Icepack_interfaces \
+      ../src/icebergs/src \
+      ../src/{FMS1,coupler,ice_param,land_null,atmos_null}
     sed -i '/FMS1\/.*\/test_/d' path_names
     ../src/mkmf/bin/mkmf -t ../src/mkmf/templates/ncrc5-$1.mk -p MOM6 -c"-Duse_libMPI -Duse_netCDF -D_USE_LEGACY_LAND_ -Duse_AM3_physics" path_names
     (source $1/env ; make NETCDF=3 REPRO=1 MOM6 -s -j)
diff --git a/.testing/Makefile b/.testing/Makefile
index 71d5b464f0..f6a6f994ae 100644
--- a/.testing/Makefile
+++ b/.testing/Makefile
@@ -71,7 +71,8 @@ MAKEFLAGS += --no-builtin-variables
 .SUFFIXES:
 
 # Determine the MOM6 autoconf srcdir
-AC_SRCDIR := $(dir $(abspath $(lastword $(MAKEFILE_LIST))))../ac
+CODEBASE := $(dir $(abspath $(lastword $(MAKEFILE_LIST))))..
+AC_SRCDIR := $(CODEBASE)/ac
 
 # User-defined configuration
 -include config.mk
@@ -144,6 +145,10 @@ BUILD ?= $(WORKSPACE)/build
 DEPS ?= $(BUILD)/deps
 WORK ?= $(WORKSPACE)/work
 
+# External tools
+MAKEDEP ?= $(abspath $(AC_SRCDIR)/makedep)
+PKG ?= $(abspath $(CODEBASE)/pkg)
+
 # Experiment configuration
 EXECS ?= symmetric/MOM6 asymmetric/MOM6 openmp/MOM6
 CONFIGS ?= $(wildcard tc*)
@@ -311,7 +316,7 @@ $(BUILD)/opt_target: | $(TARGET_CODEBASE)
 $(BUILD)/%/Makefile: $(BUILD)/%/Makefile.in $(BUILD)/%/config.status
 	cd $(@D) && ./config.status
 
-$(BUILD)/%/config.status: $(BUILD)/%/configure $(DEPS)/lib/libFMS.a
+$(BUILD)/%/config.status: $(BUILD)/%/configure $(DEPS)/lib/libFMS.a $(DEPS)/lib/libgsw.a $(DEPS)/lib/libcvmix.a
 	cd $(@D) && $(MOM_ENV) ./configure -n --srcdir=$(AC_SRCDIR) $(MOM_ACFLAGS) \
 	 || (cat config.log && false)
 
@@ -340,19 +345,18 @@ $(TARGET_CODEBASE):
 endif
 
 
-## FMS
+## Dependencies
 
 # Set up the FMS build environment variables
-FMS_ENV = \
-  PATH="${PATH}:$(realpath ../ac)" \
+DEPS_ENV = \
   FCFLAGS="$(FCFLAGS_FMS)" \
+  MAKEDEP=$(MAKEDEP) \
   REPORT_ERROR_LOGS="$(REPORT_ERROR_LOGS)"
 
-$(DEPS)/lib/libFMS.a: $(DEPS)/Makefile $(DEPS)/Makefile.fms.in $(DEPS)/configure.fms.ac $(DEPS)/m4
-	$(FMS_ENV) $(MAKE) -C $(DEPS) lib/libFMS.a
+# FMS
 
-$(DEPS)/Makefile: ../ac/deps/Makefile | $(DEPS)
-	cp ../ac/deps/Makefile $(DEPS)/Makefile
+$(DEPS)/lib/libFMS.a: $(DEPS)/Makefile $(DEPS)/Makefile.fms.in $(DEPS)/configure.fms.ac $(DEPS)/m4
+	$(DEPS_ENV) $(MAKE) -C $(DEPS) lib/libFMS.a
 
 $(DEPS)/Makefile.fms.in: ../ac/deps/Makefile.fms.in | $(DEPS)
 	cp ../ac/deps/Makefile.fms.in $(DEPS)/Makefile.fms.in
@@ -360,6 +364,33 @@ $(DEPS)/Makefile.fms.in: ../ac/deps/Makefile.fms.in | $(DEPS)
 $(DEPS)/configure.fms.ac: ../ac/deps/configure.fms.ac | $(DEPS)
 	cp ../ac/deps/configure.fms.ac $(DEPS)/configure.fms.ac
 
+# GSW
+
+$(DEPS)/lib/libgsw.a: $(DEPS)/Makefile $(DEPS)/Makefile.gsw.in $(DEPS)/configure.gsw.ac $(DEPS)/m4
+	$(DEPS_ENV) PKG=$(PKG) $(MAKE) -C $(DEPS) lib/libgsw.a
+
+$(DEPS)/Makefile.gsw.in: ../ac/deps/Makefile.gsw.in | $(DEPS)
+	cp ../ac/deps/Makefile.gsw.in $(DEPS)/Makefile.gsw.in
+
+$(DEPS)/configure.gsw.ac: ../ac/deps/configure.gsw.ac | $(DEPS)
+	cp ../ac/deps/configure.gsw.ac $(DEPS)/configure.gsw.ac
+
+# CVMix
+
+$(DEPS)/lib/libcvmix.a: $(DEPS)/Makefile $(DEPS)/Makefile.cvmix.in $(DEPS)/configure.cvmix.ac $(DEPS)/m4
+	$(DEPS_ENV) PKG=$(PKG) $(MAKE) -C $(DEPS) lib/libcvmix.a
+
+$(DEPS)/Makefile.cvmix.in: ../ac/deps/Makefile.cvmix.in | $(DEPS)
+	cp ../ac/deps/Makefile.cvmix.in $(DEPS)/Makefile.cvmix.in
+
+$(DEPS)/configure.cvmix.ac: ../ac/deps/configure.cvmix.ac | $(DEPS)
+	cp ../ac/deps/configure.cvmix.ac $(DEPS)/configure.cvmix.ac
+
+# Generic dependency content
+
+$(DEPS)/Makefile: ../ac/deps/Makefile | $(DEPS)
+	cp ../ac/deps/Makefile $(DEPS)/Makefile
+
 $(DEPS)/m4: ../ac/deps/m4 | $(DEPS)
 	cp -r ../ac/deps/m4 $(DEPS)/
 
diff --git a/.testing/tc0/MOM_input b/.testing/tc0/MOM_input
index eacf4143de..17f4826c8c 100644
--- a/.testing/tc0/MOM_input
+++ b/.testing/tc0/MOM_input
@@ -233,9 +233,11 @@ ENERGYSAVEDAYS = 1.0
 
 DIAG_AS_CHKSUM = True
 DEBUG = True
-GRID_ROTATION_ANGLE_BUGS = True !   [Boolean] default = True
-USE_GM_WORK_BUG = True          !   [Boolean] default = True
+
 USE_LAND_MASK_FOR_HVISC = False !   [Boolean] default = False
 GUST_CONST = 0.02               !   [Pa] default = 0.02
-FIX_USTAR_GUSTLESS_BUG = False  !   [Boolean] default = False
 
+! These are no longer necessary, as they are using the default value.
+GRID_ROTATION_ANGLE_BUGS = False !   [Boolean] default = False
+USE_GM_WORK_BUG = False         !   [Boolean] default = False
+USTAR_GUSTLESS_BUG = False      !   [Boolean] default = False
diff --git a/.testing/tc1.a/MOM_tc_variant b/.testing/tc1.a/MOM_tc_variant
index ff2dabe065..88a38a8fa8 100644
--- a/.testing/tc1.a/MOM_tc_variant
+++ b/.testing/tc1.a/MOM_tc_variant
@@ -1,2 +1,3 @@
-#override SPLIT=False
-#override UNSPLIT_DT_VISC_BUG = True      !   [Boolean] default = False
+#override SPLIT = False
+#override UNSPLIT_DT_VISC_BUG = False     !   [Boolean] default = False
+#override EQN_OF_STATE = "ROQUET_RHO"     ! default = "WRIGHT_FULL"
diff --git a/.testing/tc1.b/MOM_tc_variant b/.testing/tc1.b/MOM_tc_variant
index 878e582546..7e3d0aa6bd 100644
--- a/.testing/tc1.b/MOM_tc_variant
+++ b/.testing/tc1.b/MOM_tc_variant
@@ -1,3 +1,7 @@
-#override SPLIT=False
-#override USE_RK2=True
-#override UNSPLIT_DT_VISC_BUG = True      !   [Boolean] default = False
+#override SPLIT = False
+#override USE_RK2 = True
+#override UNSPLIT_DT_VISC_BUG = False     !   [Boolean] default = False
+
+! There may be a problem with one of these settings.
+! #override EQN_OF_STATE = "ROQUET_SPV"     ! default = "WRIGHT_FULL"
+! #override BOUSSINESQ = FALSE
diff --git a/.testing/tc1/MOM_input b/.testing/tc1/MOM_input
index ea16da62a8..c7add5d5b7 100644
--- a/.testing/tc1/MOM_input
+++ b/.testing/tc1/MOM_input
@@ -584,28 +584,27 @@ ENERGYSAVEDAYS = 0.125          !   [days] default = 3600.0
 DIAG_AS_CHKSUM = True
 DEBUG = True
 USE_PSURF_IN_EOS = False        !   [Boolean] default = False
-GRID_ROTATION_ANGLE_BUGS = True !   [Boolean] default = True
 INTERPOLATE_RES_FN = True       !   [Boolean] default = True
 GILL_EQUATORIAL_LD = False      !   [Boolean] default = False
-USE_GM_WORK_BUG = True          !   [Boolean] default = True
 USE_LAND_MASK_FOR_HVISC = False !   [Boolean] default = False
-KAPPA_SHEAR_ITER_BUG = True     !   [Boolean] default = True
-KAPPA_SHEAR_ALL_LAYER_TKE_BUG = True !   [Boolean] default = True
-BULKML_CONV_MOMENTUM_BUG = True !   [Boolean] default = True
 PEN_SW_ABSORB_MINTHICK = 0.001  !   [m] default = 0.001
 GUST_CONST = 0.02               !   [Pa] default = 0.02
-FIX_USTAR_GUSTLESS_BUG = False  !   [Boolean] default = False
 
 
-! Explicitly use the defaults from late 2024
-EQN_OF_STATE = "WRIGHT"     ! default = "WRIGHT_FULL"
-HOR_DIFF_ANSWER_DATE = 20240101
-HOR_DIFF_LIMIT_BUG = True
+! Updated defaults reflecting the model status in late 2025
+DRAG_DIFFUSIVITY_ANSWER_DATE = 20251231
+EQN_OF_STATE = "WRIGHT_FULL"     ! default = "WRIGHT_FULL"
+HOR_DIFF_ANSWER_DATE = 20251231
+MASS_WEIGHT_IN_PRESSURE_GRADIENT_TOP = True !   [Boolean] default = True
+
+! These are no longer necessary, as they are using the default value.
+HOR_DIFF_LIMIT_BUG = False      !   [Boolean] default = False
+GRID_ROTATION_ANGLE_BUGS = False !   [Boolean] default = False
+USE_GM_WORK_BUG = False         !   [Boolean] default = False
+USTAR_GUSTLESS_BUG = False      !   [Boolean] default = False
+KAPPA_SHEAR_ITER_BUG = False    !   [Boolean] default = False
+KAPPA_SHEAR_ALL_LAYER_TKE_BUG = False !   [Boolean] default = False
+VISC_REM_BUG = False            !   [Boolean] default = False
+FRICTWORK_BUG = False           !   [Boolean] default = False
+BULKML_CONV_MOMENTUM_BUG = False !   [Boolean] default = False
 
-! Explicitly use the defaults from early 2025
-VISC_REM_BUG = True
-DRAG_DIFFUSIVITY_ANSWER_DATE = 20250101
-FRICTWORK_BUG = True
-HOR_DIFF_ANSWER_DATE = 20240101
-HOR_DIFF_LIMIT_BUG = True
-MASS_WEIGHT_IN_PRESSURE_GRADIENT_TOP = False
diff --git a/.testing/tc2/MOM_input b/.testing/tc2/MOM_input
index 77a2a92678..fea7ca25d1 100644
--- a/.testing/tc2/MOM_input
+++ b/.testing/tc2/MOM_input
@@ -616,27 +616,29 @@ ENERGYSAVEDAYS = 0.5            !   [days] default = 3600.0
                                 ! energies of the run and other globally summed diagnostics.
 DIAG_AS_CHKSUM = True
 DEBUG = True
-USE_GM_WORK_BUG = False
+
 USE_PSURF_IN_EOS = False        !   [Boolean] default = False
-GRID_ROTATION_ANGLE_BUGS = True !   [Boolean] default = True
 REMAP_UV_USING_OLD_ALG = True   !   [Boolean] default = True
 USE_LAND_MASK_FOR_HVISC = False !   [Boolean] default = False
-KAPPA_SHEAR_ITER_BUG = True     !   [Boolean] default = True
-KAPPA_SHEAR_ALL_LAYER_TKE_BUG = True !   [Boolean] default = True
 USE_MLD_ITERATION = False       !   [Boolean] default = False
 PEN_SW_ABSORB_MINTHICK = 0.001  !   [m] default = 0.001
 GUST_CONST = 0.02               !   [Pa] default = 0.02
-FIX_USTAR_GUSTLESS_BUG = False  !   [Boolean] default = False
 
-! Explicitly use the defaults from late 2024
+! Updated defaults reflecting the model status in late 2025
 EQN_OF_STATE = "WRIGHT"     ! default = "WRIGHT_FULL"
-TIDES_ANSWER_DATE = 20230630
-NDIFF_ANSWER_DATE = 20240101
-BACKSCATTER_UNDERBOUND = True
+TIDES_ANSWER_DATE = 20251231
+NDIFF_ANSWER_DATE = 20251231
+DRAG_DIFFUSIVITY_ANSWER_DATE = 20251231
+MASS_WEIGHT_IN_PRESSURE_GRADIENT_TOP = True !   [Boolean] default = True
+
+! These are no longer necessary, as they are using the default value.
+GRID_ROTATION_ANGLE_BUGS = False !   [Boolean] default = False
+USE_GM_WORK_BUG = False         !   [Boolean] default = False
+USTAR_GUSTLESS_BUG = False      !   [Boolean] default = False
+KAPPA_SHEAR_ITER_BUG = False    !   [Boolean] default = False
+KAPPA_SHEAR_ALL_LAYER_TKE_BUG = False !   [Boolean] default = False
+VISC_REM_BUG = False            !   [Boolean] default = False
+FRICTWORK_BUG = False           !   [Boolean] default = False
 
-! Explicitly use the defaults from early 2025
-VISC_REM_BUG = True
-DRAG_DIFFUSIVITY_ANSWER_DATE = 20250101
-FRICTWORK_BUG = True
-NDIFF_ANSWER_DATE = 20240101
-MASS_WEIGHT_IN_PRESSURE_GRADIENT_TOP = False
+
+BACKSCATTER_UNDERBOUND = True
diff --git a/.testing/tc2/MOM_tc_variant b/.testing/tc2/MOM_tc_variant
index 8cdbf69de8..fd7e20784d 100644
--- a/.testing/tc2/MOM_tc_variant
+++ b/.testing/tc2/MOM_tc_variant
@@ -10,3 +10,6 @@ TIDE_Q1 = True
 TIDE_MF = True
 TIDE_MM = True
 TIDE_SAL_SCALAR_VALUE = 1.
+BT_STRONG_DRAG = True           !   [Boolean] default = False
+RESCALE_STRONG_DRAG = True      !   [Boolean] default = False
+
diff --git a/.testing/tc3/MOM_input b/.testing/tc3/MOM_input
index 41ccf286aa..0c6a503db4 100644
--- a/.testing/tc3/MOM_input
+++ b/.testing/tc3/MOM_input
@@ -473,15 +473,18 @@ ENERGYSAVEDAYS = 3.0            !   [hours] default = 1.44E+04
 DIAG_AS_CHKSUM = True
 DEBUG = True
 OBC_RADIATION_MAX = 10.0        !   [nondim] default = 10.0
-GRID_ROTATION_ANGLE_BUGS = True !   [Boolean] default = True
-USE_GM_WORK_BUG = True          !   [Boolean] default = True
+
 USE_LAND_MASK_FOR_HVISC = False !   [Boolean] default = False
-KAPPA_SHEAR_ITER_BUG = True     !   [Boolean] default = True
-KAPPA_SHEAR_ALL_LAYER_TKE_BUG = True !   [Boolean] default = True
 GUST_CONST = 0.02               !   [Pa] default = 0.02
-FIX_USTAR_GUSTLESS_BUG = False  !   [Boolean] default = False
 
-! Explicitly use the defaults from early 2025
-VISC_REM_BUG = True
-DRAG_DIFFUSIVITY_ANSWER_DATE = 20250101
-FRICTWORK_BUG = True
+! Updated defaults reflecting the model status in late 2025
+DRAG_DIFFUSIVITY_ANSWER_DATE = 20251231
+
+! These are no longer necessary, as they are using the default value.
+GRID_ROTATION_ANGLE_BUGS = False !   [Boolean] default = False
+USE_GM_WORK_BUG = False         !   [Boolean] default = False
+USTAR_GUSTLESS_BUG = False      !   [Boolean] default = False
+KAPPA_SHEAR_ITER_BUG = False    !   [Boolean] default = False
+KAPPA_SHEAR_ALL_LAYER_TKE_BUG = False !   [Boolean] default = False
+VISC_REM_BUG = False            !   [Boolean] default = False
+FRICTWORK_BUG = False           !   [Boolean] default = False
diff --git a/.testing/tc4/.gitignore b/.testing/tc4/.gitignore
index 4f9cc2826f..0532a48da7 100644
--- a/.testing/tc4/.gitignore
+++ b/.testing/tc4/.gitignore
@@ -3,7 +3,9 @@ aclocal.m4
 autom4te.cache/
 config.log
 config.status
+configure
 configure~
+Makefile
 
 # Output
 gen_grid
diff --git a/.testing/tc4/MOM_input b/.testing/tc4/MOM_input
index 94ac6a7be8..fc9c42298d 100644
--- a/.testing/tc4/MOM_input
+++ b/.testing/tc4/MOM_input
@@ -92,10 +92,6 @@ ROTATION = "betaplane"          ! default = "2omegasinlat"
                                 !     USER - call a user modified routine.
 F_0 = 1.0E-04                   !   [s-1] default = 0.0
                                 ! The reference value of the Coriolis parameter with the betaplane option.
-GRID_ROTATION_ANGLE_BUGS = True !   [Boolean] default = False
-                                ! If true, use an older algorithm to calculate the sine and cosines needed
-                                ! rotate between grid-oriented directions and true north and east.  Differences
-                                ! arise at the tripolar fold.
 
 ! === module MOM_tracer_registry ===
 
@@ -234,9 +230,6 @@ KV = 1.0E-04                    !   [m2 s-1]
 ! === module MOM_thickness_diffuse ===
 KHTH = 500.0                    !   [m2 s-1] default = 0.0
                                 ! The background horizontal thickness diffusivity.
-USE_GM_WORK_BUG = True          !   [Boolean] default = False
-                                ! If true, compute the top-layer work tendency on the u-grid with the incorrect
-                                ! sign, for legacy reproducibility.
 
 ! === module MOM_porous_barriers ===
 
@@ -381,9 +374,6 @@ WIND_CONFIG = "zero"            !
                                 ! options include (file), (2gyre), (1gyre), (gyres), (zero), and (USER).
 GUST_CONST = 0.02               !   [Pa] default = 0.0
                                 ! The background gustiness in the winds.
-FIX_USTAR_GUSTLESS_BUG = False  !   [Boolean] default = True
-                                ! If true correct a bug in the time-averaging of the gustless wind friction
-                                ! velocity
 
 ! === module MOM_main (MOM_driver) ===
 DAYMAX = 0.25                   !   [days]
@@ -412,11 +402,15 @@ DEBUG = True
 INTERPOLATE_RES_FN = True       !   [Boolean] default = True
 GILL_EQUATORIAL_LD = False      !   [Boolean] default = False
 USE_LAND_MASK_FOR_HVISC = False !   [Boolean] default = False
-KAPPA_SHEAR_ITER_BUG = True     !   [Boolean] default = True
-KAPPA_SHEAR_ALL_LAYER_TKE_BUG = True !   [Boolean] default = True
 USE_MLD_ITERATION = False       !   [Boolean] default = False
 
-! Explicitly use the defaults from early 2025
-VISC_REM_BUG = True
-FRICTWORK_BUG = True
-MASS_WEIGHT_IN_PRESSURE_GRADIENT_TOP = False
+MASS_WEIGHT_IN_PRESSURE_GRADIENT_TOP = True !   [Boolean] default = True
+
+! These are no longer necessary, as they are using the default value.
+GRID_ROTATION_ANGLE_BUGS = False !   [Boolean] default = False
+USE_GM_WORK_BUG = False         !   [Boolean] default = False
+USTAR_GUSTLESS_BUG = False      !   [Boolean] default = False
+KAPPA_SHEAR_ITER_BUG = False    !   [Boolean] default = False
+KAPPA_SHEAR_ALL_LAYER_TKE_BUG = False !   [Boolean] default = False
+VISC_REM_BUG = False            !   [Boolean] default = False
+FRICTWORK_BUG = False           !   [Boolean] default = False
diff --git a/.testing/tc4/configure.ac b/.testing/tc4/configure.ac
index c431ad65ef..4b9ad55a06 100644
--- a/.testing/tc4/configure.ac
+++ b/.testing/tc4/configure.ac
@@ -47,24 +47,29 @@ AX_FC_CHECK_C_LIB([netcdf], [nc_create], [], [
 ])
 
 # Confirm that the Fortran compiler can link to the netCDF Fortran library.
-# NOTE:
-#   - We test nf_create, rather than nf90_create, since AX_FC_CHECK_LIB can
-#     not currently probe the Fortran 90 interfaces.
-#   - nf-config does not have --libdir, so we parse the --flibs output.
-AX_FC_CHECK_LIB([netcdff], [nf_create], [], [], [
-  AS_UNSET([ax_fc_cv_lib_netcdff_nf_create])
-  AC_PATH_PROG([NF_CONFIG], [nf-config])
-  AS_IF([test -n "$NF_CONFIG"], [
-    AC_SUBST([LDFLAGS],
-      ["$LDFLAGS $($NF_CONFIG --flibs | xargs -n1 | grep "^-L" | sort -u | xargs)"]
+# NOTE: nf-config does not have --libdir, so we parse the --flibs output.
+MOM6_FC_CHECK_LIB([netcdff], [nf90_create], [netcdf], [path,cmode,ncid], [rc], [
+        character :: path
+        integer :: cmode, ncid, rc],
+  [], [
+    AS_UNSET([mom6_fc_cv_lib_netcdff_nf90_create])
+    AC_PATH_PROG([NF_CONFIG], [nf-config])
+    AS_IF([test -n "$NF_CONFIG"], [
+      AC_SUBST([LDFLAGS],
+        ["$LDFLAGS $($NF_CONFIG --flibs | xargs -n1 | grep "^-L" | sort -u | xargs)"]
+      )
+    ], [
+      AC_MSG_ERROR([Could not find nf-config.])
+    ])
+    MOM6_FC_CHECK_LIB([netcdff], [nf90_create], [netcdf], [path,cmode,ncid], [rc], [
+        character :: path
+        integer :: cmode, ncid, rc],
+      [], [
+        AC_MSG_ERROR([Could not find netCDF Fortran library.])
+      ]
     )
-  ], [
-    AC_MSG_ERROR([Could not find nf-config.])
-  ])
-  AX_FC_CHECK_LIB([netcdff], [nf_create], [], [], [
-    AC_MSG_ERROR([Could not find netCDF Fortran library.])
-  ])
-])
+  ]
+)
 
 
 AC_CONFIG_FILES([Makefile])
diff --git a/CLAUDE.md b/CLAUDE.md
new file mode 100644
index 0000000000..20d535d948
--- /dev/null
+++ b/CLAUDE.md
@@ -0,0 +1,591 @@
+# MOM6 rules for agent-assisted development
+
+## Purpose of this document
+
+This file guides [Claude Code](https://docs.anthropic.com/en/docs/claude-code) -- Anthropic's agentic
+command-line tool for software development -- when working on the MOM6 codebase. Claude Code uses Claude,
+Anthropic's AI assistant, to read and edit files, run shell commands, search codebases, and interact with
+git and GitHub, all from the terminal. It is available via `npm install -g @anthropic-ai/claude-code`
+or at https://claude.ai/download.
+
+When Claude Code operates inside a repository, it reads this `CLAUDE.md` file automatically
+to learn project-specific conventions, coding standards, and development workflows. Everything
+below captures the patterns, rules, and best practices that govern MOM6 development -- drawn
+from the official wiki, ReadTheDocs documentation, CI infrastructure, and the coding style
+of important historical PRs. Following these guidelines ensures that AI-generated contributions
+match the quality and consistency expected by the MOM6 community.
+
+This is a **living document** intended to be constantly updated as both the MOM6 codebase
+and Claude's capabilities evolve. As developers gain experience using Claude Code on MOM6,
+common mistakes and new best practices should be added here. See the
+"Common Claude Mistakes" section at the end of this file -- it is expected to grow over time.
+
+## Project Overview
+
+MOM6 (Modular Ocean Model, version 6) is a next-generation open-source ocean model developed by NOAA-GFDL. It combines the best of GOLD and MOM5 into a modern Fortran codebase solving the primitive equations for ocean dynamics on an Arakawa C-grid. Key features:
+
+- Arbitrary Lagrangian-Eulerian (ALE) vertical coordinate
+- Boussinesq and non-Boussinesq modes
+- Flexible equation of state (Wright, TEOS-10, linear)
+- Comprehensive parameterization library (ePBL, KPP, lateral mixing, tidal forcing)
+- Coupled to SIS2 (sea ice), ice shelves, and Earth system models via FMS/NUOPC/MCT
+- Dimensional unit scaling for consistency testing
+
+### Language & Environment
+
+- **Language**: Fortran 2003+ (free-form `.F90`, preprocessed)
+- **Build systems**: Autoconf (primary), CMake (experimental), GNU Make for testing
+- **Dependencies**: FMS framework, CVMix, GSW-Fortran (TEOS-10)
+- **Compilers**: Must compile under GNU, Intel, and PGI
+- **Testing**: Comprehensive CI via GitHub Actions and GFDL GitLab pipeline
+- **Repository**: https://github.com/NOAA-GFDL/MOM6
+- **Documentation**: https://mom6.readthedocs.io/en/main/
+- **Examples**: https://github.com/NOAA-GFDL/MOM6-examples/wiki
+- **Main branch**: `dev/gfdl` (GFDL development); `main` (inter-lab coordination)
+
+## Code Style & Conventions
+
+### Formatting Rules
+
+- **Indentation**: 2 spaces (no tabs, ever)
+- **Continuation lines**: minimum 4 spaces indent
+- **Line length**: target 100 characters for code; absolute maximum 120 (enforced by `.testing/trailer.py`)
+- **No trailing whitespace** (enforced by CI)
+- **`enddo`** and **`endif`** (single words); but `end module`, `end subroutine`, `end function`, `end type`
+- Space after language tokens: `if (x > 0)` not `if(x > 0)`
+- No space between function name and `(`: `call fn(x)` not `call fn (x)`
+- Space around assignment `=`; but no spaces in loop bounds: `do i=is,ie`
+- Named arguments: `call fn(arg_name=val)` (no spaces around `=`)
+
+### Module Structure
+
+Every module follows this pattern:
+
+```fortran
+!> Brief module description
+module MOM_module_name
+
+! This file is part of MOM6. See LICENSE.md for the license.
+
+use MOM_some_module, only : specific_symbol
+use MOM_other,       only : other_thing
+
+implicit none ; private
+
+#include <MOM_memory.h>
+
+public :: exported_routine_1, exported_routine_2
+
+!> Control structure for this module
+type, public :: module_CS ; private
+  real :: param         !< Description [units]
+  integer :: id_diag = -1 !< Diagnostic ID for some_field
+end type module_CS
+
+contains
+
+!> Initialize the module, read parameters, register diagnostics
+subroutine module_init(Time, G, GV, US, param_file, diag, CS)
+  ! ... call log_version, get_param, register_diag_field ...
+end subroutine module_init
+
+!> Deallocate module memory
+subroutine module_end(CS)
+  ! ... cleanup ...
+end subroutine module_end
+
+!> \namespace MOM_module_name
+!! Extended description, references, and equations
+end module MOM_module_name
+```
+
+Key rules:
+- **`implicit none ; private`** on a single line in every module
+- **Explicit `only` imports** on all `use` statements -- no blanket imports
+- **No global/module data** -- all state lives in control structures passed as arguments
+- **All arguments must have declared `intent`** (`in`, `out`, or `inout`); pointers exempt
+- **Every module has `_init` and `_end` subroutines** for lifecycle management
+- **`! Local variables`** comment separates dummy arguments from local declarations in subroutines
+- **Prefer `allocatable` over `pointer`** for control structure members
+
+### Naming Conventions
+
+- **Files**: `MOM_something.F90` (module inside is `MOM_something`)
+- **Variables**: `snake_case` for multi-word names (Doxygen-compatible)
+- **Control structures**: `module_CS` (e.g., `energetic_PBL_CS`), always `private`
+- **Diagnostic IDs**: `id_diag_name`, initialized to `-1`
+- **Inverses**: prefix with `I` (e.g., `IdxCu` = `1/dxCu`, `IareaT` = `1/areaT`)
+- **Grid objects**: `G` (ocean_grid_type), `GV` (verticalGrid_type), `US` (unit_scale_type)
+- **Public functions**: self-documenting names; private helpers may use short names
+
+### Loop Index Conventions (Soft Case)
+
+This is a critical MOM6 convention for the Arakawa C-grid staggering:
+
+- **Lowercase `i`, `j`, `k`**: cell-center / layer-center (tracer points). Example: `h(i,j,k)`, `T(i,j,k)`
+- **Uppercase `I`, `J`**: cell-edge / staggered points (north-east convention). `I` = i+½. Example: `u(I,j,k)`, `v(i,J,k)`, `q(I,J,k)`
+- **Uppercase `K`**: vertical interface. `K=1` is above layer `k=1`; `K` = k-½. Example: `e(i,j,K)`
+- **Domain bounds**: `is, ie, js, je` (computational); `isd, ied, jsd, jed` (data/halo)
+- **Grid locations**: T (tracer/h-points), Cu (u-points), Cv (v-points), Bu (q/vertex-points)
+
+### Memory Macros
+
+Array dimensions use preprocessor macros from `MOM_memory.h`:
+- `SZI_(G)`, `SZJ_(G)`, `SZK_(GV)` for explicit-shape arrays
+- `NIMEM_`, `NJMEM_`, `NKMEM_` for allocatable arrays
+
+## Unit Documentation (Critical Convention)
+
+MOM6 uses a dimensional annotation system for every real variable. Units are documented in square brackets at the end of comments, using a two-part notation:
+
+```
+[rescaled_dimensions ~> MKS_equivalent]
+```
+
+### Dimensional Symbols
+
+| Symbol | Physical Dimension | MKS Unit |
+|--------|-------------------|----------|
+| Z | Vertical depth/distance | m |
+| L | Horizontal length | m |
+| T | Time | s |
+| H | Layer thickness | m (Boussinesq) or kg m-2 |
+| R | Density | kg m-3 |
+| Q | Enthalpy | J kg-1 |
+| C | Temperature | degC |
+| S | Salinity | ppt |
+| A | Arbitrary/generic units | a |
+
+### Examples
+
+```fortran
+real :: velocity     !< Horizontal velocity [L T-1 ~> m s-1]
+real :: pressure     !< Hydrostatic pressure [R L2 T-2 ~> Pa]
+real :: thickness    !< Layer thickness [H ~> m or kg m-2]
+real :: diffusivity  !< Vertical diffusivity [Z2 T-1 ~> m2 s-1]
+real :: slope        !< Isopycnal slope [Z L-1 ~> nondim]
+real :: efficiency   !< Mixing efficiency [nondim]
+real :: field        !< A field in arbitrary units [A]
+real :: Z_to_m       !< Scaling factor [m Z-1 ~> 1]
+```
+
+### Unit Annotation Rules
+
+1. **Every real variable** must have units in `[brackets]` at the end of its comment
+2. **Canonical symbol ordering**: consistent order (e.g., `H L2` not `L2 H`)
+3. **Boussinesq variants first**: `[H ~> m or kg m-2]` when units differ by approximation
+4. **Simplified expressions only**: write `[T2 Z-1 ~> s2 m-1]`, not `[H Z T-1 / H Z2 T-3 = T2 Z-1 ~> s2 m-1]`
+5. **Exponent notation**: `m-1`, `s-2`, `kg-3` (no slashes like `1/m`)
+6. **No extra spaces** inside brackets
+7. **Nondimensional**: use `[nondim]`
+8. **Arbitrary/generic**: use `[A]` or `[A ~> a]`, never `[arbitrary]`
+9. **Scaling factors**: `[target source-1 ~> 1]`, e.g., `[Z m-1 ~> 1]`
+
+## Arithmetic and Reproducibility
+
+MOM6 demands bitwise reproducibility across processor counts and build modes. These rules are non-negotiable:
+
+1. **Parenthesize all additions**: `z = (a + b) + c` not `z = a + b + c`
+2. **Never use `sum()`, `prod()`, or `matmul()` intrinsics** -- operation order is undefined
+3. **Pre-compute reciprocals**: `Q * G%IareaT(i,j)` not `Q / G%areaT(i,j)`
+4. **Never write `B / C * D`**: use `(B * D) / C` (explicit grouping)
+5. **Avoid the exponent operator `**`**: write `a * a * a` not `a**3` (compilers emit transcendental `pow()`)
+6. **Avoid transcendental functions** where possible (sin, cos, log, non-integer powers are implementation-dependent)
+7. **`sqrt()` is safe** (IEEE-754 exactly rounded); use MOM6's `cuberoot` for cube roots
+8. **Explicit parenthesization for FP precision**: group unit-conversion factors before multiplying data
+   ```fortran
+   tmp = ( ( tv%C_p * GV%H_to_RZ ) * h(i,j,k) ) * tv%T(i,j,k)
+   ```
+9. **Vanished layer pattern**: `h + h_neglect` (not `max(h, h_neglect)`)
+
+### Array Syntax
+
+- **Prohibited**: `tv%S = 0.` (scalar-looking whole-array assignment)
+- **Allowed**: `tv%S(:,:,:) = 0.` (explicit colon notation)
+- **Prohibited**: array-syntax math on arrays that include halos (halo data may be invalid)
+
+## Doxygen Documentation
+
+### Comment Syntax
+
+- `!>` for documentation comments on the following entity
+- `!<` for inline documentation on the preceding entity (same line)
+- `!!` for multi-line continuation (no blank lines between)
+- `!>@{` and `!>@}` for grouping related declarations
+
+### Requirements
+
+- **All public subroutines/functions**: `!>` header describing purpose
+- **All arguments**: documented with `!<` or `!>` including units
+- **All type members**: documented with `!<` including units
+- **All real variables**: must include physical description and units
+- **Equations**: LaTeX with `\f$ ... \f$` (inline) or `\f[ ... \f]` (display)
+- **Extended descriptions**: placed before `end module` using `\namespace`
+
+## Parameter System
+
+Runtime parameters are read via `get_param()`, not hardcoded:
+
+```fortran
+#include "version_variable.h"
+character(len=40) :: mdl = "MOM_module_name"
+
+call log_version(param_file, mdl, version, "")
+call get_param(param_file, mdl, "PARAM_NAME", CS%variable, &
+               "Description of this parameter.", &
+               units="m s-1", default=1.0, scale=US%m_s_to_L_T)
+```
+
+- Parameters documented in auto-generated `MOM_parameter_doc.all` files
+- Use `scale=` argument for unit conversion from MKS input to internal units
+- Always provide `default=` when sensible; use `fail_if_missing=.true.` otherwise
+- Use `do_not_log=.not.CS%Feature` to suppress logging when a parent feature is inactive
+
+### Answer-Changing Parameters: `_BUG` Flags and `ANSWER_DATE`
+
+When a bug fix or improvement changes numerical answers, MOM6 uses two mechanisms to preserve backward compatibility:
+
+**`_BUG` flags**: Boolean parameters that retain old (buggy) behavior by default:
+```fortran
+call get_param(param_file, mdl, "OBC_TEMP_SALT_NEEDED_BUG", OBC%ts_needed_bug, &
+               "If true, recover a bug that OBC temperature and salinity can be ignored "//&
+               "even if they are registered tracers in the rest of the model.", default=.true.)
+```
+- Name format: `FEATURE_BUG` (e.g., `VISC_REM_BUG`, `FRICTWORK_BUG`, `KAPPA_SHEAR_ITER_BUG`)
+- Default is `.true.` (bug ON, old behavior preserved)
+- Description starts with "If true, recover a bug that..."
+- Users opt into the fix by setting to `.false.`
+
+**`ANSWER_DATE` flags**: Integer dates selecting algorithm versions:
+```fortran
+call get_param(param_file, mdl, "HOR_DIFF_ANSWER_DATE", CS%answer_date, &
+               "...", default=99991231)
+```
+- Format: `YYYYMMDD` (e.g., `20251231`)
+- `DEFAULT_ANSWER_DATE` provides a single knob to update all answer-date defaults
+- `ENABLE_BUGS_BY_DEFAULT=False` activates all bug fixes (recommended for new configurations)
+
+## Diagnostics
+
+### Registration Pattern
+
+```fortran
+CS%id_field = register_diag_field('ocean_model', 'field_name', diag%axesTL, Time, &
+    'Long description of the field', units='m s-1', conversion=US%L_T_to_m_s)
+```
+
+### Posting Pattern
+
+```fortran
+if (CS%id_field > 0) call post_data(CS%id_field, field_array, CS%diag)
+```
+
+Key conventions:
+- `conversion=` handles unit scaling so output is always in MKS
+- `v_extensive=.true.` for vertically integrated quantities
+- Guard computation with `if (id > 0)` to avoid unnecessary work
+- Standard diagnostic name prefixes follow CMOR conventions when applicable
+
+### Masking and Missing Values
+
+- **Never set diagnostic arrays to a missing value** before passing to `post_data()`. Masking of land/invalid points is handled automatically by the diagnostics infrastructure based on the diagnostic's registered axes.
+- **Do not pass `mask=` to `post_data()`** for non-static diagnostics on standard grids -- the infrastructure applies the correct mask automatically.
+- **Do pass `mask=`** for static fields (`is_static=.true.`), non-standard masks, or sub-domain-sized arrays.
+- **Never compare field values against `missing_value`** in unit-conversion code -- rescaling can cause valid data to coincidentally match the missing value sentinel.
+
+## Testing
+
+### Test Suite Overview
+
+The `.testing/` directory provides comprehensive verification. Build and run:
+
+```bash
+make -C .testing -j build/symmetric/MOM6   # Build reference executable
+make -C .testing -j test                    # Run full test suite
+make -C .testing -j build.unit             # Build unit tests
+make -C .testing -j run.unit               # Run unit tests
+```
+
+### Test Categories
+
+| Test | Verifies |
+|------|----------|
+| `test.grid` | Symmetric vs asymmetric grids produce identical results |
+| `test.layout` | Serial vs parallel decomposition identical |
+| `test.rotate` | Rotational invariance |
+| `test.restart` | Continuous run vs restart-and-continue identical |
+| `test.repro` | DEBUG and REPRO builds identical |
+| `test.openmp` | Serial vs OpenMP identical |
+| `test.nan` | NaN-initialization doesn't affect results |
+| `test.dim.{t,l,h,z,q,r}` | Dimensional rescaling invariance (time, length, thickness, depth, enthalpy, density) |
+| `test.regression` | Current code vs target branch (PRs only) |
+
+### Test Configurations
+
+- `tc0` -- Unit tests
+- `tc1` / `tc1.a` / `tc1.b` -- Benchmark (split RK2, unsplit RK3, unsplit RK2)
+- `tc2` / `tc2.a` -- ALE with tides / sigma-coordinate PPM_H4
+- `tc3` -- Open boundary conditions
+- `tc4` -- Sponges and I/O initialization
+
+### Verification Method
+
+- `ocean.stats` -- total energy at machine precision
+- `chksum_diag` -- mean/min/max/bitcount checksums in physical domain
+- Tests pass only when output is **bitwise identical** between configurations
+
+### Style Checking
+
+```bash
+./.testing/trailer.py -e TEOS10 -l 120 src config_src
+```
+
+Checks for tabs, trailing whitespace, and line length violations.
+
+## Git Workflow & Contribution
+
+### Branch Strategy
+
+- **Work on forks**, not branches on the primary repository
+- **Branch from `dev/gfdl`** for all new work
+- **Never rebase a pushed branch**
+- Submit changes via pull requests to `dev/gfdl`
+
+### Commit Message Format
+
+```
+Short imperative summary (aim for ~50 chars)
+
+  Detailed explanation indented by 2 spaces, wrapped at ~80 columns.
+  Describe what was changed and why. Reference issues with #NNN.
+  All answers are bitwise identical.
+```
+
+Conventions from the lead developers:
+- **`*` prefix** on title if the commit changes numerical answers (checksums)
+- **`+` prefix** on title to indicate new public interfaces or parameters
+- **`*+` or `+*`** when both answer-changing and adding new interfaces
+- No prefix for refactoring, cleanup, or comment-only changes that are bitwise identical
+- **Always state impact on numerical results**: "All answers are bitwise identical" or explain what changes
+- **Multi-commit PRs**: introduce infrastructure first, use it in a second commit
+- **Minimize public scope**: only export symbols needed by other modules; remove from `public` when refactoring makes a symbol internal-only
+- **Comment closing `enddo`/`endif`** for non-trivial nested loops: `enddo ! n-loop for segments`
+
+### PR Description Style
+
+1. Lead with a clear explanation of what changed and why
+2. Quantify scope (e.g., "across 26 files", "in 7 places")
+3. For answer-changing PRs, provide scientific justification
+4. State the bitwise-identical guarantee (or explain what changes and why)
+5. When a fix could change answers, protect with a runtime parameter defaulting to `.false.`
+
+### CI Pipeline
+
+On every push and PR, GitHub Actions runs:
+1. Style and Doxygen checks
+2. Builds across 8 configurations (symmetric, asymmetric, repro, openmp, target, opt, coverage, coupled API)
+3. All test groups in parallel
+4. Code coverage reporting
+5. For PRs: regression testing and timing comparison against target branch
+
+Additionally, GFDL's internal GitLab runs ~400 tests across 59 configurations on Gaea HPC (GNU/Intel/PGI, debug/repro).
+
+## Source Directory Structure
+
+```
+src/
+  core/                          # Dynamical core
+    MOM.F90                      # Main stepping routines (~5000 lines)
+    MOM_barotropic.F90           # Barotropic solver (~6700 lines)
+    MOM_continuity_PPM.F90       # PPM-based continuity
+    MOM_dynamics_split_RK2.F90   # Split RK2 time stepping
+    MOM_grid.F90                 # Horizontal grid type
+    MOM_variables.F90            # Common variable types
+    MOM_verticalGrid.F90         # Vertical grid type
+    MOM_PressureForce_FV.F90     # Finite-volume pressure gradient
+  ALE/                           # Vertical remapping/regridding
+    MOM_ALE.F90                  # ALE driver
+    MOM_regridding.F90           # Vertical grid generation
+    MOM_remapping.F90            # Conservative remapping
+    Recon1d_*.F90                # 1D reconstruction schemes (PLM, PPM, PQM, WENO, etc.)
+  diagnostics/                   # Diagnostic calculations
+    MOM_diagnostics.F90          # Standard diagnostics
+    MOM_diagnose_MLD.F90         # Mixed layer depth
+  equation_of_state/             # EOS implementations
+    MOM_EOS.F90                  # EOS wrapper
+    MOM_EOS_Wright.F90           # Wright (1997) EOS
+    MOM_EOS_TEOS10.F90           # TEOS-10 EOS
+  framework/                     # Infrastructure
+    MOM_diag_mediator.F90        # Diagnostics framework
+    MOM_file_parser.F90          # Parameter file parsing
+    MOM_unit_scaling.F90         # Dimensional scaling system
+    MOM_domains.F90              # Domain decomposition
+    MOM_restart.F90              # Restart I/O
+  ice_shelf/                     # Ice shelf dynamics
+  initialization/                # Grid/state initialization
+  ocean_data_assim/              # Data assimilation
+  parameterizations/
+    lateral/                     # Lateral parameterizations
+      MOM_hor_visc.F90           # Horizontal viscosity
+      MOM_thickness_diffuse.F90  # Thickness diffusion (GM)
+      MOM_MEKE.F90               # Mesoscale eddy kinetic energy
+      MOM_Zanna_Bolton.F90       # Zanna-Bolton backscatter
+    vertical/                    # Vertical mixing
+      MOM_energetic_PBL.F90      # ePBL mixed layer (~4500 lines)
+      MOM_CVMix_KPP.F90          # KPP via CVMix
+      MOM_diabatic_driver.F90    # Diabatic processes driver
+      MOM_set_diffusivity.F90    # Background diffusivity
+      MOM_vert_friction.F90      # Vertical friction
+  tracer/                        # Tracer transport and specific tracers
+  user/                          # Idealized configuration initialization
+config_src/
+  drivers/
+    solo_driver/                 # Ocean-only standalone (simplest; testing)
+    FMS_cap/                     # GFDL coupler
+    nuopc_cap/                   # NUOPC/CESM coupling
+    unit_tests/                  # Unit test executables
+    timing_tests/                # Performance benchmarks
+  memory/
+    dynamic_symmetric/           # Symmetric memory layout (default)
+    dynamic_nonsymmetric/        # Asymmetric memory layout
+  infra/                         # FMS1/FMS2 wrappers
+  external/                      # Null hooks for optional components
+pkg/
+  CVMix-src/                     # Community Vertical Mixing
+  GSW-Fortran/                   # TEOS-10 Gibbs Seawater
+```
+
+## Physics Domain Knowledge
+
+### Governing Equations
+- Primitive equations with hydrostatic or Boussinesq approximation
+- ALE vertical coordinate: Lagrangian dynamics with periodic remapping
+- Split barotropic-baroclinic time stepping (RK2 split or unsplit RK3)
+- Free surface dynamics (implicit barotropic solver)
+
+### Numerical Methods
+- Finite volume on Arakawa C-grid (staggered: velocities at cell faces, tracers at centers)
+- PPM (Piecewise Parabolic Method) for tracer advection and continuity
+- Various reconstruction schemes: PLM, PPM, PQM, WENO, PLM-WLS
+- Pressure gradient force via finite-volume integration
+- Reproducing global sums for parallel reproducibility
+
+### Key Physical Parameterizations
+- **ePBL**: Energetically consistent planetary boundary layer (Hallberg)
+- **KPP**: K-Profile Parameterization via CVMix
+- **Gent-McWilliams/Redi**: Thickness and isopycnal diffusion
+- **MEKE**: Mesoscale eddy kinetic energy budget
+- **Zanna-Bolton**: Data-driven subgrid momentum closure
+- **Tidal forcing**: Astronomical and self-attraction/loading
+
+## Common Development Tasks
+
+### Adding a New Parameterization
+1. Create `MOM_new_param.F90` in the appropriate `src/parameterizations/` subdirectory
+2. Define a control structure type (`new_param_CS`) with `private` members
+3. Implement `new_param_init()`: read parameters via `get_param`, register diagnostics
+4. Implement the main computational subroutine
+5. Implement `new_param_end()` for cleanup
+6. Wire it into the calling module (e.g., `MOM_diabatic_driver.F90`)
+7. Document all variables with proper units
+8. Add unit tests in `config_src/drivers/unit_tests/` if applicable
+9. Run the full test suite: `make -C .testing -j test`
+
+### Adding a New Diagnostic
+1. Add `integer :: id_new_diag = -1` to the control structure
+2. Register in `_init` with `register_diag_field('ocean_model', 'name', axes, Time, ...)`
+3. Compute and post with `if (CS%id_new_diag > 0) call post_data(CS%id_new_diag, array, CS%diag)`
+4. Include `conversion=` for unit scaling to MKS output
+5. Provide CMOR standard name when applicable
+
+### Adding a Runtime Parameter
+1. Add member to control structure with units documentation
+2. Call `get_param(param_file, mdl, "PARAM_NAME", CS%param, "description", units="...", default=...)`
+3. Use `scale=` for dimensional conversion from MKS input
+4. If the parameter could change answers, default to preserving existing behavior
+
+### Fixing a Bug
+- Always state whether the fix changes answers in the commit message
+- **Any change that alters existing numerical answers** -- whether a bug fix, accuracy improvement, or algorithmic reorganization -- must provide a runtime parameter (`_BUG` flag or `ANSWER_DATE`) to toggle between old and new behavior, with the default preserving old behavior
+- This applies even when the developer's tests show negligible differences -- existing users may be in production runs
+- Trace through secondary effects before concluding the fix is safe
+- Run `test.regression` to verify impact
+
+## Architecture: Infrastructure Layering
+
+MOM6 has a strict dependency hierarchy that must never be violated:
+
+```
+config_src/infra/  -->  src/framework/  -->  src/core/, src/parameterizations/, etc.
+```
+
+- **`config_src/infra/`** (FMS1/FMS2 wrappers) must **never** import from `src/framework/`
+- **Code duplication** between infra and framework is acceptable to maintain this invariant
+- FMS1 and FMS2 infra directories must expose the same public API
+- API changes to infra-level functions must be checked against downstream consumers (SIS2, ice shelf code)
+
+## Defensive Programming
+
+- **Check `allocated()` / `associated()`** before accessing arrays tied to optional features (e.g., features controlled by runtime parameters like `FRAZIL` may not allocate all related arrays)
+- **Short-circuit evaluation**: put allocation checks first in compound conditions: `if (allocated(arr) .and. (condition))`
+- **Type-correct comparisons**: when comparing real-valued masks, use `== 1.` not `== 1`
+- **FATAL error messages** should include: file name, subroutine name, and the specific condition or input that triggered the error
+- **Validate user inputs early**: check for duplicates, overflow, and missing required fields in configuration parsing; include the problematic input string in error messages
+- **Mark known issues** with `!###` comment prefix
+
+## Common Pitfalls
+
+1. **Forgetting units in comments**: every `real` variable needs `[units]`
+2. **Unparenthesized arithmetic**: causes non-reproducible results across compilers
+3. **Using `**` operator**: triggers transcendental `pow()` -- write explicit multiplications
+4. **Module-level data**: no globals; pass everything through arguments
+5. **Missing `only` on imports**: all `use` statements require explicit imports
+6. **Array syntax with halos**: halo data is not guaranteed valid; use explicit loops
+7. **Blanket `use` imports**: never `use module` without `only`
+8. **Tabs in source**: CI will fail; use spaces only
+9. **Trailing whitespace**: CI will fail
+10. **`sum()` intrinsic**: operation order undefined across compilers
+11. **Soft case index convention**: use uppercase `I`, `J` for velocity-face indices, lowercase `i`, `j` for tracer-cell -- Fortran is case-insensitive but this convention is enforced in review
+12. **Answer-changing without a `_BUG` flag**: any numerical change requires a runtime parameter to preserve old behavior
+13. **Unnecessary `mask=` in `post_data()`**: the infrastructure handles masking automatically for non-static diagnostics
+14. **Accessing unallocated optional arrays**: always check `allocated()` before using arrays tied to optional features
+
+## Helpful Resources
+
+- MOM6 documentation: https://mom6.readthedocs.io/en/main/
+- MOM6 developers wiki: https://github.com/NOAA-GFDL/MOM6/wiki
+- MOM6 code style guide: https://github.com/NOAA-GFDL/MOM6/wiki/Code-style-guide
+- MOM6 Doxygen conventions: https://github.com/NOAA-GFDL/MOM6/wiki/Doxygen
+- MOM6 examples wiki: https://github.com/NOAA-GFDL/MOM6-examples/wiki
+- MOM6 repository policies: https://github.com/NOAA-GFDL/MOM6-examples/wiki/MOM6-repository-policies
+- MOM6 developer workflow: https://github.com/NOAA-GFDL/MOM6/wiki/Developer-workflow
+- MOM6 runtime parameters: https://github.com/NOAA-GFDL/MOM6/wiki/MOM6-run-time-parameter-system
+- MOM6 forum: https://bb.cgd.ucar.edu/cesm/forums/mom6.148/
+- CVMix documentation: https://github.com/CVMix/CVMix-src
+- TEOS-10 (GSW): http://www.teos-10.org/
+- GOTM (General Ocean Turbulence Model): https://gotm.net/
+
+### Key References
+
+The project bibliography lives in `docs/references.bib` and `docs/zotero.bib`. Consult these
+when citing prior work in Doxygen documentation or commit messages.
+
+## AI Assistant Behavior
+
+- **Follow existing patterns**: read surrounding code before making changes
+- **Document all units**: every real variable gets `[units]` annotation
+- **Parenthesize arithmetic**: explicit grouping for reproducibility
+- **State answer impact**: always note whether changes are bitwise identical
+- **Use `get_param`**: never hardcode parameters; always read from parameter files
+- **Register diagnostics properly**: guard with `if (id > 0)`, use `conversion=`
+- **Maintain lifecycle**: implement `_init` and `_end` for new modules
+- **Run tests**: `make -C .testing -j test` before any PR
+- **Respect the C-grid**: use correct staggering (soft case convention for indices)
+- **Write Doxygen comments**: `!>` for entities, `!<` for inline, with units
+
+## Common Claude Mistakes
+
+This section catalogs recurring mistakes that Claude makes when working on MOM6 code.
+It should be updated as new patterns emerge from experience.
+
+*(No entries yet -- add mistakes here as they are discovered.)*
diff --git a/ac/Makefile.in b/ac/Makefile.in
index c4d23efdfb..1821bda43d 100644
--- a/ac/Makefile.in
+++ b/ac/Makefile.in
@@ -14,8 +14,7 @@ CPPFLAGS = @CPPFLAGS@
 FCFLAGS = @FCFLAGS@
 LDFLAGS = @LDFLAGS@
 LIBS = @LIBS@
-SRC_DIRS = @SRC_DIRS@
-
+MAKEDEP_FLAGS = @MAKEDEP_FLAGS@
 
 -include Makefile.dep
 
@@ -31,8 +30,8 @@ rwildcard=$(foreach d,$(wildcard $(1:=/*)),$(call rwildcard,$d,$2) $(filter $(su
 # Generate dependencies
 .PHONY: depend
 depend: Makefile.dep
-Makefile.dep: $(MAKEDEP) $(call rwildcard,$(SRC_DIRS),*.h *.c *.inc *.F90)
-	$(PYTHON) $(MAKEDEP) $(DEFS) -o Makefile.dep -e $(SRC_DIRS)
+Makefile.dep: $(call rwildcard,$(SRC_DIRS),*.h *.c *.inc *.F90)
+	$(PYTHON) $(MAKEDEP) $(DEFS) -o Makefile.dep $(MAKEDEP_FLAGS)
 
 
 # Delete any files associated with configuration (including the Makefile).
diff --git a/ac/configure.ac b/ac/configure.ac
index 071f43f5a9..5f60a4b7da 100644
--- a/ac/configure.ac
+++ b/ac/configure.ac
@@ -51,7 +51,7 @@ AS_VAR_IF([MOM_MEMORY], [],
 )
 
 # Confirm that MOM_MEMORY is named 'MOM_memory.h'
-AS_IF([test $(basename "${MOM_MEMORY}") == "MOM_memory.h"], [],
+AS_IF([test $(basename "${MOM_MEMORY}") = "MOM_memory.h"], [],
  [AC_MSG_ERROR([MOM_MEMORY header ${MOM_MEMORY} must be named 'MOM_memory.h'])]
 )
 
@@ -138,31 +138,36 @@ AX_FC_CHECK_C_LIB([netcdf], [nc_create], [], [
 ])
 
 # Confirm that the Fortran compiler can link to the netCDF Fortran library.
-# NOTE:
-#   - We test nf_create, rather than nf90_create, since AX_FC_CHECK_LIB can
-#     not currently probe the Fortran 90 interfaces.
-#   - nf-config does not have --libdir, so we parse the --flibs output.
-AX_FC_CHECK_LIB([netcdff], [nf_create], [], [], [
-  AS_UNSET([ax_fc_cv_lib_netcdff_nf_create])
-  AC_PATH_PROG([NF_CONFIG], [nf-config])
-  AS_IF([test -n "$NF_CONFIG"], [
-    AC_SUBST([LDFLAGS],
-      ["$LDFLAGS $($NF_CONFIG --flibs | xargs -n1 | grep "^-L" | sort -u | xargs)"]
+# NOTE: nf-config does not have --libdir, so we parse the --flibs output.
+MOM6_FC_CHECK_LIB([netcdff], [nf90_create], [netcdf], [path,cmode,ncid], [rc], [
+        character :: path
+        integer :: cmode, ncid, rc],
+  [], [
+    AS_UNSET([mom6_fc_cv_lib_netcdff_nf90_create])
+    AC_PATH_PROG([NF_CONFIG], [nf-config])
+    AS_IF([test -n "$NF_CONFIG"], [
+      AC_SUBST([LDFLAGS],
+        ["$LDFLAGS $($NF_CONFIG --flibs | xargs -n1 | grep "^-L" | sort -u | xargs)"]
+      )
+    ], [
+      AC_MSG_ERROR([Could not find nf-config.])
+    ])
+    MOM6_FC_CHECK_LIB([netcdff], [nf90_create], [netcdf], [path,cmode,ncid], [rc], [
+        character :: path
+        integer :: cmode, ncid, rc],
+      [], [
+        AC_MSG_ERROR([Could not find netCDF Fortran library.])
+      ]
     )
-  ], [
-    AC_MSG_ERROR([Could not find nf-config.])
-  ])
-  AX_FC_CHECK_LIB([netcdff], [nf_create], [], [], [
-    AC_MSG_ERROR([Could not find netCDF Fortran library.])
-  ])
-])
+  ]
+)
 
 
 # Force 8-byte reals
 AX_FC_REAL8
-AS_IF(
-  [test "$enable_real8" != no],
-  [FCFLAGS="$FCFLAGS $REAL8_FCFLAGS"])
+AS_IF([test "$enable_real8" != no],
+  [FCFLAGS="$FCFLAGS $REAL8_FCFLAGS"]
+)
 
 
 # OpenMP configuration
@@ -177,8 +182,7 @@ m4_version_prereq([2.69], [AC_OPENMP], [
 ])
 
 # NOTE: Only apply OpenMP flags if explicitly enabled.
-AS_IF(
-  [test "$enable_openmp" = yes], [
+AS_IF([test "$enable_openmp" = yes], [
   FCFLAGS="$FCFLAGS $OPENMP_FCFLAGS"
   LDFLAGS="$LDFLAGS $OPENMP_FCFLAGS"
 ])
@@ -192,19 +196,22 @@ AX_FC_CHECK_MODULE([fms_mod], [], [
   AX_FC_CHECK_MODULE([fms_mod],
     [AC_SUBST([FCFLAGS], ["-I${srcdir}/ac/deps/include $FCFLAGS"])],
     [AC_MSG_ERROR([Could not find fms_mod Fortran module.])],
-    [-I${srcdir}/ac/deps/include])
+    [-I${srcdir}/ac/deps/include]
+  )
 ])
 
 # Test for fms_init to verify FMS library linking
-AX_FC_CHECK_LIB([FMS], [fms_init], [fms_mod],
+MOM6_FC_CHECK_LIB([FMS], [fms_init], [fms_mod], [], [], [],
   [], [
-    AS_UNSET([ax_fc_cv_lib_FMS_fms_init])
-    AX_FC_CHECK_LIB([FMS], [fms_init], [fms_mod], [
-      AC_SUBST([LDFLAGS], ["-L${srcdir}/ac/deps/lib $LDFLAGS"])
-      AC_SUBST([LIBS], ["-lFMS $LIBS"])
-    ],
-    [AC_MSG_ERROR([Could not find FMS library.])],
-    [-L${srcdir}/ac/deps/lib])
+    AS_UNSET([mom6_fc_cv_lib_FMS_fms_init])
+    MOM6_FC_CHECK_LIB([FMS], [fms_init], [fms_mod], [], [], [],
+      [
+        AC_SUBST([LDFLAGS], ["-L${srcdir}/ac/deps/lib $LDFLAGS"])
+        AC_SUBST([LIBS], ["-lFMS $LIBS"])
+      ], [
+        AC_MSG_ERROR([Could not find FMS library.])
+      ], [-L${srcdir}/ac/deps/lib]
+    )
   ]
 )
 
@@ -231,7 +238,29 @@ AX_FC_CHECK_MODULE([fms2_io_mod], [
 ])
 
 
-# Python interpreter test
+# GSW configuration
+AX_FC_CHECK_MODULE([gsw_mod_toolbox], [], [
+  AC_MSG_ERROR([Could not find module gsw_mod_toolbox.])
+])
+MOM6_FC_CHECK_LIB([gsw], [gsw_rho], [gsw_mod_toolbox], [sa,ct,p], [rho], [],
+  [], [
+    AC_MSG_ERROR([Could not find gsw_rho in gsw_mod_toolbox.])
+  ]
+)
+
+
+# CVMix configuration
+AX_FC_CHECK_MODULE([cvmix_kpp], [], [
+  AC_MSG_ERROR([Could not find module cvmix_kpp.])
+])
+MOM6_FC_CHECK_LIB([cvmix], [cvmix_init_kpp], [cvmix_kpp], [], [], [],
+  [], [
+    AC_MSG_ERROR([Could not find cvmix_update_wrap in cvmix_utils.])
+  ]
+)
+
+
+## Python configuration
 
 # Declare the Python interpreter variable
 AC_ARG_VAR([PYTHON], [Python interpreter command])
@@ -255,14 +284,33 @@ AC_PATH_PROG([MAKEDEP], [makedep], [${srcdir}/ac/makedep])
 AC_SUBST([MAKEDEP])
 
 
-# Generate source list and configure dependency command
-AC_SUBST([SRC_DIRS], ["\\
+# Generate Makedep source list and configure dependency command
+MAKEDEP_FLAGS="-e"
+
+# NOTE: Some pattern rules for this multiline flag constructor.
+#   - Previous args have no line continuation, so the next arg leads with `\\`.
+#   - Flag lines precede with a space ` -s` for syntax clarity.
+EXCLUDE_DIRS="\\
+  -s ${srcdir}/src/equation_of_state/TEOS10 \\
+  -s ${srcdir}/src/parameterizations/CVmix"
+
+# TODO: This may be optional in the future, so we use AS_IF.
+AS_IF([test -n "${EXCLUDE_DIRS}"], [
+  MAKEDEP_FLAGS="${MAKEDEP_FLAGS} ${EXCLUDE_DIRS}"
+])
+
+SRC_DIRS="\\
   ${srcdir}/src \\
   ${MODEL_FRAMEWORK} \\
   ${srcdir}/config_src/external \\
   ${DRIVER_DIR} \\
-  ${MOM_MEMORY_DIR}"]
-)
+  ${MOM_MEMORY_DIR}"
+MAKEDEP_FLAGS="${MAKEDEP_FLAGS} ${SRC_DIRS}"
+
+MAKEDEP_FLAGS="${MAKEDEP_FLAGS# }"
+AC_SUBST([MAKEDEP_FLAGS])
+
+# Add makedep to config.status
 AC_CONFIG_COMMANDS(Makefile.dep, [make depend])
 
 
diff --git a/ac/deps/.gitignore b/ac/deps/.gitignore
index 8cfaa6ebcb..80256cfe1d 100644
--- a/ac/deps/.gitignore
+++ b/ac/deps/.gitignore
@@ -1,5 +1,7 @@
 /bin/
 /fms/
+/gsw/
+/cvmix/
 /include/
 /lib/
 /mkmf/
diff --git a/ac/deps/Makefile b/ac/deps/Makefile
index 01431cef8c..93f3e588db 100644
--- a/ac/deps/Makefile
+++ b/ac/deps/Makefile
@@ -10,6 +10,12 @@ MAKEFLAGS += -R
 FMS_URL ?= https://github.com/NOAA-GFDL/FMS.git
 FMS_COMMIT ?= 2023.03
 
+GSW_URL ?= https://github.com/mom-ocean/GSW-Fortran.git
+GSW_COMMIT ?= 29e64d652786e1d076a05128c920f394202bfe10
+
+CVMIX_URL ?= https://github.com/mom-ocean/CVMix-src.git
+CVMIX_COMMIT ?= 65ef5c73bc7f5663d5688f75c3855d431da4baea
+
 
 # List of source files to link this Makefile's dependencies to model Makefiles
 # Assumes a depth of two, and the following extensions: F90 inc c h
@@ -18,64 +24,102 @@ SOURCE = \
   $(foreach ext,F90 inc c h,$(wildcard $(1)/*/*.$(ext) $(1)/*/*/*.$(ext)))
 
 FMS_SOURCE = $(call SOURCE,fms/src)
+GSW_SOURCE = $(call SOURCE,gsw/src)
+CVMIX_SOURCE = $(call SOURCE,CVMix-src/src/shared)
 
 
 # If `true`, print logs if an error is encountered.
 REPORT_ERROR_LOGS ?=
 
 
+# If set, use the submodule repositories in pkg/
+PKG ?= $(abspath ../../pkg)
+MAKEDEP ?= $(abspath ../makedep)
+
 #---
 # Rules
 
 .PHONY: all
 all: lib/libFMS.a
+all: lib/libgsw.a
+all: lib/libcvmix.a
 
 
-#---
-# FMS build
+# Library build rules template
+#
+# $(1): target library
+# $(2): dependency label
+# $(3): library source files
 
-# NOTE: We emulate the automake `make install` stage by storing libFMS.a to
-#   ${srcdir}/deps/lib and copying module files to ${srcdir}/deps/include.
-lib/libFMS.a: fms/build/libFMS.a
-	mkdir -p lib include
-	cp fms/build/libFMS.a lib/libFMS.a
-	cp fms/build/*.mod include
+define LIB_RULES
+lib/$(1): $(2)/build/$(1)
+	mkdir -p $$(@D) include/
+	cp $$< $$@
+	cp $$(dir $$<)/*.mod include/
 
-fms/build/libFMS.a: fms/build/Makefile
-	$(MAKE) -C fms/build libFMS.a
+$(2)/build/$(1): $(2)/build/Makefile
+	$$(MAKE) -C $$(@D) $(1)
 
-fms/build/Makefile: fms/build/Makefile.in fms/build/configure
-	cd $(@D) && { \
+$(2)/build/Makefile: $(2)/build/Makefile.in $(2)/build/configure
+	cd $$(@D) && { \
+	  MAKEDEP=$$(MAKEDEP) \
 	  ./configure --srcdir=../src \
 	  || { \
-	    if [ "${REPORT_ERROR_LOGS}" = true ]; then cat config.log ; fi ; \
+	    if [ "$${REPORT_ERROR_LOGS}" = true ]; then cat config.log ; fi ; \
 	    false; \
 	  } \
 	}
 
-fms/build/Makefile.in: Makefile.fms.in | fms/build
-	cp Makefile.fms.in fms/build/Makefile.in
+$(2)/build/Makefile.in: Makefile.$(2).in | $(2)/build
+	cp $$< $$@
+
+$(2)/build/configure: $(2)/build/configure.ac $(3) | $(2)/src
+	autoreconf $$(@D)
+
+$(2)/build/configure.ac: configure.$(2).ac m4 | $(2)/build
+	cp $$< $$@
+	cp -r m4 $$(@D)
+
+$(2)/build:
+	mkdir -p $$@
+endef
 
-fms/build/configure: fms/build/configure.ac $(FMS_SOURCE) | fms/src
-	autoreconf fms/build
+$(eval $(call LIB_RULES,libFMS.a,fms,$(FMS_SOURCE)))
+$(eval $(call LIB_RULES,libgsw.a,gsw,$(GSW_SOURCE)))
+$(eval $(call LIB_RULES,libcvmix.a,cvmix,$(CVMIX_SOURCE)))
 
-fms/build/configure.ac: configure.fms.ac m4 | fms/build
-	cp configure.fms.ac fms/build/configure.ac
-	cp -r m4 fms/build
 
-fms/build:
-	mkdir -p fms/build
+# Dependency source
 
 fms/src:
 	git clone $(FMS_URL) $@
 	git -C $@ checkout $(FMS_COMMIT)
 
+
+ifdef PKG
+gsw/src: | gsw/build
+	ln -s $(PKG)/GSW-Fortran gsw/src
+
+cvmix/src: | cvmix/build
+	ln -s $(PKG)/CVMix-src cvmix/src
+
+else
+gsw/src:
+	git clone $(GSW_URL) $@
+	git -C $@ checkout $(GSW_COMMIT)
+
+cvmix/src:
+	git clone $(CVMIX_URL) $@
+	git -C $@ checkout $(CVMIX_COMMIT)
+endif
+
+
 # Cleanup
 
 .PHONY: clean
 clean:
-	rm -rf fms/build lib include
+	rm -rf fms/build gsw/build cvmix/build lib include
 
 .PHONY: distclean
 distclean: clean
-	rm -rf fms
+	rm -rf fms gsw cvmix
diff --git a/ac/deps/Makefile.cvmix.in b/ac/deps/Makefile.cvmix.in
new file mode 100644
index 0000000000..b8254d9b11
--- /dev/null
+++ b/ac/deps/Makefile.cvmix.in
@@ -0,0 +1,30 @@
+# Makefile template for CVMix
+#
+# Compiler flags are configured by autoconf's configure script.
+#
+# Source code dependencies are configured by makedep and saved to Makefile.dep.
+
+FC = @FC@
+LD = @FC@
+AR = @AR@
+PYTHON = @PYTHON@
+MAKEDEP = @MAKEDEP@
+
+DEFS = @DEFS@
+CPPFLAGS = @CPPFLAGS@
+FCFLAGS = @FCFLAGS@
+LDFLAGS = @LDFLAGS@
+LIBS = @LIBS@
+ARFLAGS = @ARFLAGS@
+
+-include Makefile.dep
+
+# Generate Makefile from template
+Makefile: Makefile.in config.status
+	./config.status
+
+
+.PHONY: depend
+depend: Makefile.dep
+Makefile.dep:
+	$(PYTHON) $(MAKEDEP) $(DEFS) -o Makefile.dep -e -x libcvmix.a @srcdir@/src/shared
diff --git a/ac/deps/Makefile.gsw.in b/ac/deps/Makefile.gsw.in
new file mode 100644
index 0000000000..5cbc14bbbe
--- /dev/null
+++ b/ac/deps/Makefile.gsw.in
@@ -0,0 +1,30 @@
+# Makefile template for GSW
+#
+# Compiler flags are configured by autoconf's configure script.
+#
+# Source code dependencies are configured by makedep and saved to Makefile.dep.
+
+FC = @FC@
+LD = @FC@
+AR = @AR@
+PYTHON = @PYTHON@
+MAKEDEP = @MAKEDEP@
+
+DEFS = @DEFS@
+CPPFLAGS = @CPPFLAGS@
+FCFLAGS = @FCFLAGS@
+LDFLAGS = @LDFLAGS@
+LIBS = @LIBS@
+ARFLAGS = @ARFLAGS@
+
+-include Makefile.dep
+
+# Generate Makefile from template
+Makefile: Makefile.in config.status
+	./config.status
+
+
+.PHONY: depend
+depend: Makefile.dep
+Makefile.dep:
+	$(PYTHON) $(MAKEDEP) $(DEFS) -o Makefile.dep -e -x libgsw.a @srcdir@
diff --git a/ac/deps/configure.cvmix.ac b/ac/deps/configure.cvmix.ac
new file mode 100644
index 0000000000..714ab803a4
--- /dev/null
+++ b/ac/deps/configure.cvmix.ac
@@ -0,0 +1,91 @@
+# Autoconf configuration
+AC_PREREQ([2.63])
+
+AC_INIT(
+    [GSW],
+    [ ],
+    [https://github.com/TEOS-10/GSW-Fortran/issues])
+
+# Validate srdcir and configure input
+AC_CONFIG_SRCDIR([src/shared/cvmix_utils.F90])
+AC_CONFIG_MACRO_DIR([m4])
+
+
+# Build dependencies
+AC_ARG_VAR([PYTHON], [Python interpreter command])
+AC_ARG_VAR([MAKEDEP], [Makefile dependency generator])
+
+
+# Fortran configuration
+AC_LANG([Fortran])
+AC_FC_SRCEXT([f90])
+AC_PROG_FC
+
+
+# netCDF configuration
+
+# Check for netcdf.h header function declarations.
+# If unavailable, then try to invoke nc-create.
+AC_LANG_PUSH([C])
+AC_CHECK_HEADERS([netcdf.h], [], [
+  AS_UNSET([ac_cv_header_netcdf_h])
+  AC_PATH_PROG([NC_CONFIG], [nc-config])
+  AS_IF([test -n "$NC_CONFIG"], [
+      AC_SUBST([CPPFLAGS], ["$CPPFLAGS -I$($NC_CONFIG --includedir)"])
+    ],
+    [AC_MSG_ERROR([Could not find nc-config.])]
+  )
+  AC_CHECK_HEADERS([netcdf.h], [], [
+    AC_MSG_ERROR([Could not find netcdf.h])
+  ])
+])
+AC_LANG_POP([C])
+
+# Search for the Fortran netCDF module, fallback to nf-config.
+AX_FC_CHECK_MODULE([netcdf], [], [
+  AS_UNSET([ax_fc_cv_mod_netcdf])
+  AC_PATH_PROG([NF_CONFIG], [nf-config])
+  AS_IF([test -n "$NF_CONFIG"], [
+      AC_SUBST([FCFLAGS], ["$FCFLAGS -I$($NF_CONFIG --includedir)"])
+    ],
+    [AC_MSG_ERROR([Could not find nf-config.])]
+  )
+  AX_FC_CHECK_MODULE([netcdf], [], [
+    AC_MSG_ERROR([Could not find netcdf module.])
+  ])
+])
+
+
+# Verify that Python is available
+AS_IF([test -z "$PYTHON"], [
+  AC_PATH_PROGS([PYTHON], [python python3 python2])
+])
+AS_IF([test -z "$PYTHON"], [
+  AC_MSG_ERROR([Could not find python.])
+])
+AC_SUBST([PYTHON])
+
+
+# Verify that makedep is available
+AS_IF([test -z "$MAKEDEP"], [
+  AC_PATH_PROG([MAKEDEP], [makedep])
+])
+AS_IF([test -z "$MAKEDEP"], [
+  AC_MSG_ERROR([Could not find makedep.])
+])
+AC_SUBST([MAKEDEP])
+
+
+# Autoconf does not configure the archiver (ar), as it is handled by Automake.
+AR=ar
+ARFLAGS=rv
+AC_SUBST([AR])
+AC_SUBST([ARFLAGS])
+
+AC_CONFIG_COMMANDS([Makefile.dep], [make depend])
+
+AC_SUBST([CPPFLAGS])
+
+# Prepare output
+AC_CONFIG_FILES([Makefile])
+AC_OUTPUT
diff --git a/ac/deps/configure.fms.ac b/ac/deps/configure.fms.ac
index 7d68daa3c7..dfc7ad7a21 100644
--- a/ac/deps/configure.fms.ac
+++ b/ac/deps/configure.fms.ac
@@ -11,6 +11,11 @@ AC_CONFIG_SRCDIR([fms/fms.F90])
 AC_CONFIG_MACRO_DIR([m4])
 
 
+# Build dependencies
+AC_ARG_VAR([PYTHON], [Python interpreter command])
+AC_ARG_VAR([MAKEDEP], [Makefile dependency generator])
+
+
 # C configuration
 
 # Autoconf assumes that LDFLAGS can be passed to CFLAGS, even though this is
@@ -68,7 +73,7 @@ AC_CHECK_FUNCS([sched_getaffinity], [], [AC_DEFINE([__APPLE__])])
 LDFLAGS="$FC_LDFLAGS"
 
 
-# Standard Fortran configuration
+# Fortran configuration
 AC_LANG([Fortran])
 AC_FC_SRCEXT([f90])
 AC_PROG_FC
@@ -171,19 +176,23 @@ FCFLAGS="$FCFLAGS $ALLOW_ARG_MISMATCH_FCFLAGS"
 
 
 # Verify that Python is available
-AC_PATH_PROGS([PYTHON], [python python3 python2], [
+AS_IF([test -z "$PYTHON"], [
+  AC_PATH_PROGS([PYTHON], [python python3 python2])
+])
+AS_IF([test -z "$PYTHON"], [
   AC_MSG_ERROR([Could not find python.])
 ])
-AC_ARG_VAR([PYTHON], [Python interpreter command])
+AC_SUBST([PYTHON])
 
 
 # Verify that makedep is available
-AC_PATH_PROGS([MAKEDEP], [makedep], [], ["${PATH}:${srcdir}/../../.."])
-AS_IF([test -n "${MAKEDEP}"], [
-  AC_SUBST([MAKEDEP])
-], [
-  AC_MSG_ERROR(["Could not find makedep."])
+AS_IF([test -z "$MAKEDEP"], [
+  AC_PATH_PROG([MAKEDEP], [makedep])
+])
+AS_IF([test -z "$MAKEDEP"], [
+  AC_MSG_ERROR([Could not find makedep.])
 ])
+AC_SUBST([MAKEDEP])
 
 
 # Autoconf does not configure the archiver (ar), as it is handled by Automake.
diff --git a/ac/deps/configure.gsw.ac b/ac/deps/configure.gsw.ac
new file mode 100644
index 0000000000..be61eb7040
--- /dev/null
+++ b/ac/deps/configure.gsw.ac
@@ -0,0 +1,90 @@
+# Autoconf configuration
+AC_PREREQ([2.63])
+
+AC_INIT(
+    [GSW],
+    [ ],
+    [https://github.com/TEOS-10/GSW-Fortran/issues])
+
+# Validate srdcir and configure input
+AC_CONFIG_SRCDIR([modules/gsw_mod_toolbox.f90])
+AC_CONFIG_MACRO_DIR([m4])
+
+# Dependency configuration
+AC_ARG_VAR([PYTHON], [Python interpreter command])
+AC_ARG_VAR([MAKEDEP], [Makefile dependency generator])
+
+
+# Fortran compiler test
+AC_LANG([Fortran])
+AC_FC_SRCEXT([f90])
+AC_PROG_FC
+
+
+# netCDF configuration
+
+# Check for netcdf.h header function declarations.
+# If unavailable, then try to invoke nc-create.
+AC_LANG_PUSH([C])
+AC_CHECK_HEADERS([netcdf.h], [], [
+  AS_UNSET([ac_cv_header_netcdf_h])
+  AC_PATH_PROG([NC_CONFIG], [nc-config])
+  AS_IF([test -n "$NC_CONFIG"], [
+      AC_SUBST([CPPFLAGS], ["$CPPFLAGS -I$($NC_CONFIG --includedir)"])
+    ],
+    [AC_MSG_ERROR([Could not find nc-config.])]
+  )
+  AC_CHECK_HEADERS([netcdf.h], [], [
+    AC_MSG_ERROR([Could not find netcdf.h])
+  ])
+])
+AC_LANG_POP([C])
+
+# Search for the Fortran netCDF module, fallback to nf-config.
+AX_FC_CHECK_MODULE([netcdf], [], [
+  AS_UNSET([ax_fc_cv_mod_netcdf])
+  AC_PATH_PROG([NF_CONFIG], [nf-config])
+  AS_IF([test -n "$NF_CONFIG"], [
+      AC_SUBST([FCFLAGS], ["$FCFLAGS -I$($NF_CONFIG --includedir)"])
+    ],
+    [AC_MSG_ERROR([Could not find nf-config.])]
+  )
+  AX_FC_CHECK_MODULE([netcdf], [], [
+    AC_MSG_ERROR([Could not find netcdf module.])
+  ])
+])
+
+
+# Verify that Python is available
+AS_IF([test -z "$PYTHON"], [
+  AC_PATH_PROGS([PYTHON], [python python3 python2])
+])
+AS_IF([test -z "$PYTHON"], [
+  AC_MSG_ERROR([Could not find python.])
+])
+AC_SUBST([PYTHON])
+
+
+# Verify that makedep is available
+AS_IF([test -z "$MAKEDEP"], [
+  AC_PATH_PROG([MAKEDEP], [makedep])
+])
+AS_IF([test -z "$MAKEDEP"], [
+  AC_MSG_ERROR([Could not find makedep.])
+])
+AC_SUBST([MAKEDEP])
+
+
+# Autoconf does not configure the archiver (ar), as it is handled by Automake.
+AR=ar
+ARFLAGS=rv
+AC_SUBST([AR])
+AC_SUBST([ARFLAGS])
+
+AC_CONFIG_COMMANDS([Makefile.dep], [make depend])
+
+AC_SUBST([CPPFLAGS])
+
+# Prepare output
+AC_CONFIG_FILES([Makefile])
+AC_OUTPUT
diff --git a/ac/m4/mom6_fc_check_lib.m4 b/ac/m4/mom6_fc_check_lib.m4
new file mode 100644
index 0000000000..03f6496acb
--- /dev/null
+++ b/ac/m4/mom6_fc_check_lib.m4
@@ -0,0 +1,82 @@
+dnl MOM6_FC_CHECK_LIB(LIBRARY, PROCEDURE,
+dnl                   [MODULE], [ARGS], [FUNC-RESULT], [DECLS],
+dnl                   [ACTION-IF-FOUND], [ACTION-IF-NOT-FOUND],
+dnl                   [OTHER-LDFLAGS], [OTHER-LIBS])
+dnl
+dnl This macro checks if a Fortran library containing a designated function
+dnl is available to the compiler.  For the most part, this macro should behave
+dnl like the Autoconf AC_CHECK_LIB macro.
+dnl
+dnl This macro differs from AC_CHECK_LIB, since it includes several additional
+dnl arguments.  Although the next four arguments are optional, they are
+dnl required for many function tests.
+dnl
+dnl - MODULE specifies the Fortran module containing the procedure.
+dnl
+dnl - ARGS is used to specify any arguments of the procedure.
+dnl
+dnl - FUNC-RESULT, if set, identifies the procedure as a function rather than
+dnl   a subroutine, and specifies the function test result.
+dnl
+dnl - DECLS is used as a code block to explicitly declare variables, when
+dnl   implicit typing is not sufficient.
+dnl
+dnl The following argument has also been added.
+dnl
+dnl - OTHER-LDFLAGS allows specification of supplemental LDFLAGS arguments.
+dnl   This can be used, for example, to test for the library with different
+dnl   -L flags, or perhaps other ld configurations.
+dnl
+dnl Results are cached in the mom6_fc_cv_lib_LIBRARY_PROCEDURE variable.
+dnl
+AC_DEFUN([MOM6_FC_CHECK_LIB],[
+  AS_VAR_PUSHDEF([mom6_fc_Lib], [mom6_fc_cv_lib_$1_$2])
+  m4_ifval([$9],
+    [mom6_fc_lib_msg_LDFLAGS=" with $9"],
+    [mom6_fc_lib_msg_LDFLAGS=""]
+  )
+  AC_CACHE_CHECK(
+    [for $2 in -l$1$mom6_fc_lib_msg_LDFLAGS],
+    [mom6_fc_Lib],[
+      mom6_fc_check_lib_save_LDFLAGS=$LDFLAGS
+      LDFLAGS="$9 $LDFLAGS"
+      mom6_fc_check_lib_save_LIBS=$LIBS
+      LIBS="-l$1 $10 $LIBS"
+      AS_IF([test -n "$3"],
+        [mom6_fc_use_mod="use $3"],
+        [mom6_fc_use_mod=""]
+      )
+      AS_IF([test -n "$5"],
+        [mom6_fc_proc="$5 = $2"],
+        [mom6_fc_proc="call $2"]
+      )
+      AS_IF([test -n "$4"],
+        [mom6_fc_proc="${mom6_fc_proc}($4)"]
+      )
+      AS_IF([test -n "$6"],
+        [mom6_fc_decls="$6"],
+        [mom6_fc_decls=""]
+      )
+      AC_LANG_PUSH([Fortran])
+      AC_LINK_IFELSE([dnl
+dnl Begin 7-column code block
+AC_LANG_PROGRAM([], [dnl
+        $mom6_fc_use_mod
+        $mom6_fc_decls
+        $mom6_fc_proc])dnl
+dnl End code block
+        ],
+        [AS_VAR_SET([mom6_fc_Lib], [yes])],
+        [AS_VAR_SET([mom6_fc_Lib], [no])]
+      )
+      AC_LANG_POP([Fortran])
+      LIBS=$mom6_fc_check_lib_save_LIBS
+      LDFLAGS=$mom6_fc_check_lib_save_LDFLAGS
+    ]
+  )
+  AS_VAR_IF([mom6_fc_Lib], [yes],
+    [m4_default([$7], [LIBS="-l$1 $LIBS"])],
+    [$8]
+  )
+  AS_VAR_POPDEF([mom6_fc_Lib])
+])
diff --git a/config_src/drivers/FMS_cap/ocean_model_MOM.F90 b/config_src/drivers/FMS_cap/ocean_model_MOM.F90
index e3b7b0cec7..4285fcda19 100644
--- a/config_src/drivers/FMS_cap/ocean_model_MOM.F90
+++ b/config_src/drivers/FMS_cap/ocean_model_MOM.F90
@@ -372,7 +372,8 @@ subroutine ocean_model_init(Ocean_sfc, OS, Time_init, Time_in, wind_stagger, gas
 
   !allocate(OS%sfc_state)
   call allocate_surface_state(OS%sfc_state, OS%grid, use_temperature, do_integrals=.true., &
-                              gas_fields_ocn=gas_fields_ocn, use_meltpot=use_melt_pot)
+                              gas_fields_ocn=gas_fields_ocn, use_meltpot=use_melt_pot, &
+                              use_iceshelves=OS%use_ice_shelf)
 
   if (present(wind_stagger)) then
     call surface_forcing_init(Time_in, OS%grid, OS%US, param_file, OS%diag, &
diff --git a/config_src/drivers/STALE_mct_cap/mom_ocean_model_mct.F90 b/config_src/drivers/STALE_mct_cap/mom_ocean_model_mct.F90
index d1c46f4254..24e547b0e7 100644
--- a/config_src/drivers/STALE_mct_cap/mom_ocean_model_mct.F90
+++ b/config_src/drivers/STALE_mct_cap/mom_ocean_model_mct.F90
@@ -362,7 +362,8 @@ subroutine ocean_model_init(Ocean_sfc, OS, Time_init, Time_in, gas_fields_ocn, i
   !   Consider using a run-time flag to determine whether to do the diagnostic
   ! vertical integrals, since the related 3-d sums are not negligible in cost.
   call allocate_surface_state(OS%sfc_state, OS%grid, use_temperature, &
-                              do_integrals=.true., gas_fields_ocn=gas_fields_ocn, use_meltpot=use_melt_pot)
+                              do_integrals=.true., gas_fields_ocn=gas_fields_ocn, &
+                              use_meltpot=use_melt_pot, use_iceshelves=OS%use_ice_shelf)
 
   call surface_forcing_init(Time_in, OS%grid, OS%US, param_file, OS%diag, &
                             OS%forcing_CSp, OS%restore_salinity, OS%restore_temp)
diff --git a/config_src/drivers/nuopc_cap/mom_ocean_model_nuopc.F90 b/config_src/drivers/nuopc_cap/mom_ocean_model_nuopc.F90
index a83576028a..e4357dfda2 100644
--- a/config_src/drivers/nuopc_cap/mom_ocean_model_nuopc.F90
+++ b/config_src/drivers/nuopc_cap/mom_ocean_model_nuopc.F90
@@ -387,7 +387,8 @@ subroutine ocean_model_init(Ocean_sfc, OS, Time_init, Time_in, gas_fields_ocn, i
   ! vertical integrals, since the related 3-d sums are not negligible in cost.
   call allocate_surface_state(OS%sfc_state, OS%grid, use_temperature, &
                               do_integrals=.true., gas_fields_ocn=gas_fields_ocn, &
-                              use_meltpot=use_melt_pot, use_marbl_tracers=OS%use_MARBL)
+                              use_meltpot=use_melt_pot, use_iceshelves=OS%use_ice_shelf, &
+                              use_marbl_tracers=OS%use_MARBL)
 
   call surface_forcing_init(Time_in, OS%grid, OS%US, param_file, OS%diag, &
                             OS%forcing_CSp, OS%restore_salinity, OS%restore_temp, OS%use_waves)
diff --git a/config_src/infra/FMS1/MOM_interp_infra.F90 b/config_src/infra/FMS1/MOM_interp_infra.F90
index 70bc99827e..4fa3f7374b 100644
--- a/config_src/infra/FMS1/MOM_interp_infra.F90
+++ b/config_src/infra/FMS1/MOM_interp_infra.F90
@@ -4,15 +4,14 @@ module MOM_interp_infra
 ! This file is part of MOM6. See LICENSE.md for the license.
 
 use MOM_domain_infra,    only : MOM_domain_type, domain2d
-use MOM_io,              only : axis_info
-use MOM_io,              only : set_axis_info
 use MOM_time_manager,    only : time_type
 use horiz_interp_mod,    only : horiz_interp_new, horiz_interp, horiz_interp_init, horiz_interp_type
 use mpp_io_mod,          only : axistype, mpp_get_axis_data, mpp_get_atts
 use time_interp_external_mod, only : time_interp_external
 use time_interp_external_mod, only : init_external_field, time_interp_external_init
 use time_interp_external_mod, only : get_external_field_size
-use time_interp_external_mod, only : get_external_field_axes, get_external_field_missing
+use time_interp_external_mod, only : get_external_field_axes
+use time_interp_external_mod, only : get_external_field_missing
 
 implicit none ; private
 
@@ -158,34 +157,13 @@ function get_extern_field_size(index)
 end function get_extern_field_size
 
 
-!> get axes of an external field from field index
-function get_extern_field_axes(index) result(axes)
-
-  integer, intent(in) :: index    !< FMS interpolation field index
-  type(axis_info) :: axes(4)      !< MOM IO field axes handle
-
-  type(axistype), dimension(4) :: fms_axes(4)
-    ! FMS axis handles
-  character(len=32) :: name
-    ! Axis name
-  real, allocatable :: points(:)
-    ! Axis line points
-  integer :: length
-    ! Axis line point length
-  integer :: i
-    ! Loop index
-
-  fms_axes = get_external_field_axes(index)
-
-  do i = 1, 4
-    call mpp_get_atts(fms_axes(i), name=name, len=length)
+!> get size of an external field from field index
+function get_extern_field_axes(index)
 
-    allocate(points(length))
-    call mpp_get_axis_data(fms_axes(i), points)
-    call set_axis_info(axes(i), name=name, ax_data=points)
+  integer, intent(in) :: index                !< field index
+  type(axistype) :: get_extern_field_axes(4)  !< field size
 
-    deallocate(points)
-  enddo
+  get_extern_field_axes = get_external_field_axes(index)
 end function get_extern_field_axes
 
 
@@ -202,25 +180,27 @@ end function get_extern_field_missing
 
 !> Get information about the external fields.
 subroutine get_external_field_info(field, size, axes, missing)
-  type(external_field),      intent(in)    :: field     !< Handle for time interpolated external
-                                                        !! field returned from a previous
-                                                        !! call to init_external_field()
-  integer,         optional, intent(inout) :: size(4)   !< Dimension sizes for the input data
-  type(axis_info), optional, intent(inout) :: axes(4)   !< Axis types for the input data
-  real,            optional, intent(inout) :: missing   !< Missing value for the input data
+  type(external_field), intent(in) :: field
+    !< Handle for time interpolated external field returned from a previous
+    !! call to init_external_field()
+  integer, optional, intent(inout) :: size(4)
+    !< Dimension sizes for the input data
+  type(axistype), optional, intent(inout) :: axes(4)
+    !< Axis types for the input data
+  real, optional, intent(inout) :: missing
+    !< Missing value for the input data
 
   if (present(size)) then
-    size(1:4) = get_extern_field_size(field%id)
+    size(:) = get_extern_field_size(field%id)
   endif
 
   if (present(axes)) then
-    axes(1:4) = get_extern_field_axes(field%id)
+    axes(:) = get_extern_field_axes(field%id)
   endif
 
   if (present(missing)) then
     missing = get_extern_field_missing(field%id)
   endif
-
 end subroutine get_external_field_info
 
 
diff --git a/config_src/infra/FMS1/MOM_io_infra.F90 b/config_src/infra/FMS1/MOM_io_infra.F90
index e37e5db3cb..14048c611b 100644
--- a/config_src/infra/FMS1/MOM_io_infra.F90
+++ b/config_src/infra/FMS1/MOM_io_infra.F90
@@ -14,6 +14,7 @@ module MOM_io_infra
 use mpp_io_mod,           only : mpp_write_meta, mpp_write, mpp_read
 use mpp_io_mod,           only : mpp_get_atts, mpp_attribute_exist
 use mpp_io_mod,           only : mpp_get_axes, axistype, mpp_get_axis_data
+use mpp_io_mod,           only : mpp_get_axis_length
 use mpp_io_mod,           only : mpp_get_fields, fieldtype
 use mpp_io_mod,           only : mpp_get_info, mpp_get_times
 use mpp_io_mod,           only : mpp_io_init
@@ -32,7 +33,8 @@ module MOM_io_infra
 public :: open_file, open_ASCII_file, file_is_open, close_file, flush_file, file_exists
 public :: get_file_info, get_file_fields, get_file_times, get_filename_suffix
 public :: read_field, read_vector, write_metadata, write_field
-public :: field_exists, get_field_atts, get_field_size, get_axis_data, read_field_chksum
+public :: field_exists, get_field_atts, get_field_size, read_field_chksum
+public :: get_axis_size, get_axis_data, set_axis_data
 public :: io_infra_init, io_infra_end, MOM_namelist_file, check_namelist_error, write_version
 public :: stdout_if_root
 ! These types are inherited from underlying infrastructure code, to act as containers for
@@ -403,14 +405,47 @@ subroutine get_field_size(filename, fieldname, sizes, field_found, no_domain)
 
 end subroutine get_field_size
 
-!> Extracts and returns the axis data stored in an axistype.
-subroutine get_axis_data( axis, dat )
-  type(axistype),     intent(in)  :: axis !< An axis type
-  real, dimension(:), intent(out) :: dat  !< The data in the axis variable
 
-  call mpp_get_axis_data( axis, dat )
+!> Get the size of the axis
+function get_axis_size(axis) result(axis_size)
+  type(axistype), intent(in) :: axis
+    !< Infra axis
+  integer :: axis_size
+    !< Axis size
+
+  axis_size = mpp_get_axis_length(axis)
+end function get_axis_size
+
+
+!> Extracts and returns the axis data stored in an axistype.
+subroutine get_axis_data(axis, axis_name, axis_data)
+  type(axistype), intent(in) :: axis
+    !< Infra axis
+  character(len=256), intent(out) :: axis_name
+    !< Axis name
+  real, dimension(:), intent(out) :: axis_data
+    !< Axis points
+
+  call mpp_get_atts(axis, name=axis_name)
+  call mpp_get_axis_data(axis, axis_data)
 end subroutine get_axis_data
 
+
+! NOTE: Unused, but provided to match the FMS2 API
+
+!> Return a new axistype based on axis specs
+subroutine set_axis_data(axis, axis_name, axis_data)
+  type(axistype), intent(inout) :: axis
+    !< Target axis
+  character(len=256), intent(in) :: axis_name
+    !< Target axis name
+  real, intent(in) :: axis_data(:)
+    !< Target axis values
+
+  call MOM_error(FATAL, "set_axis_data in FMS1 is not yet implemented.")
+end subroutine set_axis_data
+
+
 !> This routine uses the fms_io subroutine read_data to read a scalar named
 !! "fieldname" from a single or domain-decomposed file "filename".
 subroutine read_field_0d(filename, fieldname, data, timelevel, scale, MOM_Domain, &
diff --git a/config_src/infra/FMS2/MOM_interp_infra.F90 b/config_src/infra/FMS2/MOM_interp_infra.F90
index 0b45b752ae..1e4d712c3a 100644
--- a/config_src/infra/FMS2/MOM_interp_infra.F90
+++ b/config_src/infra/FMS2/MOM_interp_infra.F90
@@ -4,10 +4,10 @@ module MOM_interp_infra
 ! This file is part of MOM6. See LICENSE.md for the license.
 
 use MOM_domain_infra,    only : MOM_domain_type, domain2d
-use MOM_io,              only : axis_info
-use MOM_io,              only : get_var_axes_info
+use MOM_io_infra, only : axistype
+use MOM_io_infra, only : set_axis_data
 use MOM_time_manager,    only : time_type
-use MOM_error_handler, only : MOM_error, FATAL
+use MOM_error_infra, only : MOM_error => MOM_err, FATAL
 use MOM_string_functions, only : lowercase
 use horiz_interp_mod, only : horiz_interp_new, horiz_interp, horiz_interp_init, horiz_interp_type
 use netcdf_io_mod, only : FmsNetcdfFile_t, netcdf_file_open, netcdf_file_close
@@ -17,6 +17,17 @@ module MOM_interp_infra
 use time_interp_external2_mod, only : get_external_field_size
 use time_interp_external2_mod, only : get_external_field_missing
 
+! Use primitive netCDF, to replicate get_var_axes_info()
+use netcdf, only : nf90_open
+use netcdf, only : nf90_close
+use netcdf, only : nf90_inq_varid
+use netcdf, only : nf90_inquire_variable
+use netcdf, only : nf90_inquire_dimension
+use netcdf, only : nf90_get_var
+use netcdf, only : NF90_NOWRITE
+use netcdf, only : NF90_NOERR
+
+
 implicit none ; private
 
 public :: horiz_interp_type, horizontal_interp_init
@@ -153,10 +164,115 @@ end function get_extern_field_size
 
 !> get axes of an external field from field index
 function get_extern_field_axes(field) result(axes)
-  type(external_field), intent(in) :: field   !< Field handle
-  type(axis_info), dimension(4) :: axes        !< Field axes
+  type(external_field), intent(in) :: field
+    !< Field handle
+  type(axistype), dimension(4) :: axes
+    !< Field axes
+
+  integer :: ndims
+    ! Number of variable dimensions
+  integer, allocatable :: dims(:)
+    ! netCDF dimension IDs of variable
+  character(len=256) :: dim_name
+    ! Dimension name
+  integer :: dim_len
+    ! Dimension length
+  integer :: var_dim
+    ! netCDF ID of the variable associated with dimension of the same name
+  real, allocatable :: axis_points(:)
+    ! Axis values
+
+  integer :: ncid
+    ! netCDF file ID
+  integer :: varid
+    ! netCDF variable ID
+  integer :: rc
+    ! netCDF return code
+
+  ! netCDF requires the following to be length-1 arrays
+  integer :: nc_start(1)
+    ! netCDF start index
+  integer :: nc_count(1)
+    ! netCDF index count
+
+  integer :: d
+    ! Dimension index
+  character(len=2) :: d_str
+    ! Display string of d
+
+  ! This is a reimplementation of get_var_axes_info(), maybe it can be used
+  ! by the existing get_var_axes_info() ?
+
+  ! Open field%filename
+  rc = nf90_open(trim(field%filename), NF90_NOWRITE, ncid)
+  if (rc /= NF90_NOERR) &
+    call MOM_error(FATAL, "Error opening file " // trim(field%filename) // ".")
+
+  ! Use field%label to get the netCDF varid
+  rc = nf90_inq_varid(ncid, trim(field%label), varid)
+  if (rc /= NF90_NOERR) &
+    call MOM_error(FATAL, "Error finding variable " // trim(field%label) &
+        // " in " // trim(field%filename) // ".")
+
+  ! Use the varid to get the number of dims (ndims) and their IDs (dims(:))
+  !   Verify that ndims >= 3
+  rc = nf90_inquire_variable(ncid, varid, ndims=ndims)
+  if (rc /= NF90_NOERR) &
+    call MOM_error(FATAL, "Error querying variable " // trim(field%label) &
+        // " in " // trim(field%filename) // ".")
+
+  if (ndims < 3) &
+    call MOM_error(FATAL, trim(field%label) // " in " // trim(field%filename) &
+        // " has too few dimensions to be read as a 3D array.")
+
+  allocate(dims(ndims))
+
+  rc = nf90_inquire_variable(ncid, varid, dimids=dims)
+  if (rc /= NF90_NOERR) &
+    call MOM_error(FATAL, "Error querying variable " // trim(field%label) &
+        // " in " // trim(field%filename) // ".")
+
+  do d=1,ndims
+    ! Determine the name of each dimension
+    rc = nf90_inquire_dimension(ncid, dims(d), dim_name, len=dim_len)
+    if (rc /= NF90_NOERR) then
+      write(d_str, '(i0)') d
+      call MOM_error(FATAL, "Error querying dimension " // trim(d_str) &
+          // " of " // trim(field%label) // " in " // trim(field%filename) &
+          // ".")
+    endif
+
+    ! Now locate a variable with the same name as the dimension (e.g. "x")
+    rc = nf90_inq_varid(ncid, dim_name, var_dim)
+    if (rc /= NF90_NOERR) &
+      call MOM_error(FATAL, "Error finding dimension variable " &
+          // trim(dim_name) // " of " // trim(field%label) // " in " &
+          // trim(field%filename))
+
+    allocate(axis_points(dim_len))
+
+    ! Get the dimensional axis values
+    nc_start(1) = 1
+    nc_count(1) = dim_len
+    rc = nf90_get_var(ncid, var_dim, axis_points, nc_start, nc_count)
+    if (rc /= NF90_NOERR) &
+      call MOM_error(FATAL, "Error reading dimension " // trim(dim_name) &
+          // " axis data of " // trim(field%label) // " in " &
+          // trim(field%filename))
+
+    ! write via set_axis_info() equivalent for axistype
+    call set_axis_data(axes(d), dim_name, axis_points)
+
+    deallocate(axis_points)
+  enddo
+
+  deallocate(dims)
+
+  ! Close external file
+  rc = nf90_close(ncid)
+  if (rc /= NF90_NOERR) &
+    call MOM_error(FATAL, "Error closing file "//trim(field%filename)//".")
 
-  call get_var_axes_info(field%filename, field%label, axes)
 end function get_extern_field_axes
 
 
@@ -173,25 +289,27 @@ end function get_extern_field_missing
 
 !> Get information about the external fields.
 subroutine get_external_field_info(field, size, axes, missing)
-  type(external_field),                   intent(in)    :: field    !< Handle for time interpolated external
-                                                                    !! field returned from a previous
-                                                                    !! call to init_external_field()
-  integer,         dimension(4), optional, intent(inout) :: size    !< Dimension sizes for the input data
-  type(axis_info), dimension(4), optional, intent(inout) :: axes    !< Axis types for the input data
-  real,                          optional, intent(inout) :: missing !< Missing value for the input data
+  type(external_field), intent(in) :: field
+    !< handle for time interpolated external field returned from a previous
+    !! call to init_external_field()
+  integer, optional, intent(inout) :: size(4)
+    !< Dimension sizes for the input data
+  type(axistype), optional, intent(inout) :: axes(4)
+    !< Axis types for the input data
+  real, optional, intent(inout) :: missing
+    !< Missing value for the input data
 
   if (present(size)) then
-    size(1:4) = get_extern_field_size(field%id)
+    size(:) = get_extern_field_size(field%id)
   endif
 
   if (present(axes)) then
-    axes(1:4) = get_extern_field_axes(field)
+    axes(:) = get_extern_field_axes(field)
   endif
 
   if (present(missing)) then
     missing = get_extern_field_missing(field%id)
   endif
-
 end subroutine get_external_field_info
 
 
diff --git a/config_src/infra/FMS2/MOM_io_infra.F90 b/config_src/infra/FMS2/MOM_io_infra.F90
index a43b4e9344..efbf53009f 100644
--- a/config_src/infra/FMS2/MOM_io_infra.F90
+++ b/config_src/infra/FMS2/MOM_io_infra.F90
@@ -6,8 +6,6 @@ module MOM_io_infra
 use MOM_domain_infra,     only : MOM_domain_type, rescale_comp_data, AGRID, BGRID_NE, CGRID_NE
 use MOM_domain_infra,     only : domain2d, domain1d, CENTER, CORNER, NORTH_FACE, EAST_FACE
 use MOM_error_infra,      only : MOM_error=>MOM_err, NOTE, FATAL, WARNING, is_root_PE
-use MOM_string_functions, only : lowercase
-
 use fms2_io_mod,          only : fms2_open_file => open_file, check_if_open, fms2_close_file => close_file
 use fms2_io_mod,          only : fms2_flush_file => flush_file
 use fms2_io_mod,          only : FmsNetcdfDomainFile_t, FmsNetcdfFile_t, fms2_read_data => read_data
@@ -46,7 +44,8 @@ module MOM_io_infra
 public :: open_file, open_ASCII_file, file_is_open, close_file, flush_file, file_exists
 public :: get_file_info, get_file_fields, get_file_times, get_filename_suffix
 public :: read_field, read_vector, write_metadata, write_field
-public :: field_exists, get_field_atts, get_field_size, get_axis_data, read_field_chksum
+public :: field_exists, get_field_atts, get_field_size, read_field_chksum
+public :: get_axis_size, get_axis_data, set_axis_data
 public :: io_infra_init, io_infra_end, MOM_namelist_file, check_namelist_error, write_version
 public :: stdout_if_root
 ! These types act as containers for information about files, fields and axes, respectively,
@@ -715,21 +714,62 @@ function find_index(vec) result(loc)
 end function find_index
 
 
+!> Get the axis size from an axistype
+function get_axis_size(axis) result(axis_size)
+  type(axistype), intent(in) :: axis
+    !< Infra axis
+  integer :: axis_size
+    !< Axis size
+
+  axis_size = size(axis%ax_data)
+end function get_axis_size
+
+
 !> Extracts and returns the axis data stored in an axistype.
-subroutine get_axis_data( axis, dat )
-  type(axistype),     intent(in)  :: axis !< An axis type
-  real, dimension(:), intent(out) :: dat  !< The data in the axis variable
+subroutine get_axis_data(axis, axis_name, axis_data)
+  type(axistype), intent(in) :: axis
+    !< Infra axis
+  character(len=256), intent(out) :: axis_name
+    !< Axis name
+  real, dimension(:), intent(out) :: axis_data
+    !< Axis points
 
   integer :: i
 
-  ! This routine might not be needed for MOM6.
   if (allocated(axis%ax_data)) then
-    if (size(axis%ax_data) > size(dat)) call MOM_error(FATAL, &
-      "get_axis_data called with too small of an output data array for "//trim(axis%name))
-    do i=1,size(axis%ax_data) ; dat(i) = axis%ax_data(i) ; enddo
+    if (size(axis%ax_data) > size(axis_data)) &
+      call MOM_error(FATAL, "get_axis_data called with too small of an " &
+          // "output data array for " // trim(axis%name) // ".")
+    do i=1,size(axis%ax_data)
+      axis_data(i) = axis%ax_data(i)
+    enddo
   endif
+
+  axis_name = axis%name
 end subroutine get_axis_data
 
+
+!> Return a new axistype based on axis specs
+subroutine set_axis_data(axis, axis_name, axis_data)
+  type(axistype), intent(inout) :: axis
+    !< Target axis
+  character(len=256), intent(in) :: axis_name
+    !< Target axis name
+  real, intent(in) :: axis_data(:)
+    !< Target axis values
+
+  axis%name = axis_name
+
+  if (allocated(axis%ax_data)) deallocate(axis%ax_data)
+  allocate(axis%ax_data(size(axis_data)))
+
+  axis%ax_data(:) = axis_data(:)
+
+  ! NOTE: We do not yet consider domain-decomposed axes.
+  axis%domain_decomposed = .false.
+end subroutine set_axis_data
+
+
 !> This routine uses the fms_io subroutine read_data to read a scalar named
 !! "fieldname" from a single or domain-decomposed file "filename".
 subroutine read_field_0d(filename, fieldname, data, timelevel, scale, MOM_Domain, &
@@ -2036,4 +2076,25 @@ function find_unlimited_dimension_name(fileobj) result(label)
     label = ''
 end function find_unlimited_dimension_name
 
+! NOTE: `lowercase is duplicated from `src/framework/MOM_string_functions.F90`
+!   in order to avoid any dependency of the infra on the framework.
+
+!> Return a string in which all uppercase letters have been replaced by
+!! their lowercase counterparts.
+function lowercase(input_string)
+  character(len=*),     intent(in) :: input_string !< The string to modify
+  character(len=len(input_string)) :: lowercase !< The modified output string
+!   This function returns a string in which all uppercase letters have been
+! replaced by their lowercase counterparts.  It is loosely based on the
+! lowercase function in mpp_util.F90.
+  integer, parameter :: co=iachar('a')-iachar('A') ! case offset
+  integer :: k
+
+  lowercase = input_string
+  do k=1, len_trim(input_string)
+    if (lowercase(k:k) >= 'A' .and. lowercase(k:k) <= 'Z') &
+        lowercase(k:k) = achar(ichar(lowercase(k:k))+co)
+  enddo
+end function lowercase
+
 end module MOM_io_infra
diff --git a/src/ALE/MOM_ALE.F90 b/src/ALE/MOM_ALE.F90
index ab9b7405ee..da93c37c10 100644
--- a/src/ALE/MOM_ALE.F90
+++ b/src/ALE/MOM_ALE.F90
@@ -53,6 +53,7 @@ module MOM_ALE
 use PLM_functions,        only : PLM_reconstruction, PLM_boundary_extrapolation
 use PLM_functions,        only : PLM_extrapolate_slope, PLM_monotonized_slope, PLM_slope_wa
 use PPM_functions,        only : PPM_reconstruction, PPM_boundary_extrapolation
+use Recon1d_PLM_WLS,      only : PLM_WLS
 
 implicit none ; private
 #include <MOM_memory.h>
@@ -140,6 +141,7 @@ module MOM_ALE
 public ALE_PLM_edge_values
 public TS_PLM_edge_values
 public TS_PPM_edge_values
+public TS_PLM_WLS_edge_values
 public adjustGridForIntegrity
 public ALE_initRegridding
 public ALE_getCoordinate
@@ -1184,9 +1186,9 @@ subroutine ALE_remap_velocities(CS, G, GV, h_old_u, h_old_v, h_new_u, h_new_v, u
       ! First get barotropic component
       u_bt = 0.0
       do k=1,nz
-        u_bt = u_bt + h2(k) * u_tgt(k) ! Dimensions [H L T-1]
+        u_bt = u_bt + h2(k) * u_tgt(k) ! Dimensions [H L T-1 ~> m2 s-1 or kg m-1 s-1]
       enddo
-      u_bt = u_bt / (sum(h2(1:nz)) + GV%H_subroundoff) ! Dimensions return to [L T-1]
+      u_bt = u_bt / (sum(h2(1:nz)) + GV%H_subroundoff) ! Dimensions return to [L T-1 ~> m s-1]
       ! Next get baroclinic ke = \int (u-u_bt)^2 from source and target
       ke_c_src = 0.0
       ke_c_tgt = 0.0
@@ -1259,9 +1261,9 @@ subroutine ALE_remap_velocities(CS, G, GV, h_old_u, h_old_v, h_new_u, h_new_v, u
       ! First get barotropic component
       v_bt = 0.0
       do k=1,nz
-        v_bt = v_bt + h2(k) * v_tgt(k) ! Dimensions [H L T-1]
+        v_bt = v_bt + h2(k) * v_tgt(k) ! Dimensions [H L T-1 ~> m2 s-1 or kg m-1 s-1]
       enddo
-      v_bt = v_bt / (sum(h2(1:nz)) + GV%H_subroundoff) ! Dimensions return to [L T-1]
+      v_bt = v_bt / (sum(h2(1:nz)) + GV%H_subroundoff) ! Dimensions return to [L T-1 ~> m s-1]
       ! Next get baroclinic ke = \int (u-u_bt)^2 from source and target
       ke_c_src = 0.0
       ke_c_tgt = 0.0
@@ -1607,11 +1609,11 @@ subroutine TS_PPM_edge_values( CS, S_t, S_b, T_t, T_b, G, GV, tv, h, bdry_extrap
   ! Local variables
   integer :: i, j, k
   real    :: hTmp(GV%ke) ! A 1-d copy of h [H ~> m or kg m-2]
-  real    :: tmp(GV%ke)  ! A 1-d copy of a column of temperature [degC] or salinity [ppt]
+  real    :: tmp(GV%ke)  ! A 1-d copy of a column of temperature [C ~> degC] or salinity [S ~> ppt]
   real, dimension(CS%nk,2) :: &
-      ppol_E            ! Edge value of polynomial in [degC] or [ppt]
+      ppol_E            ! Edge value of polynomial in [C ~> degC] or [S ~> ppt]
   real, dimension(CS%nk,3) :: &
-      ppol_coefs        ! Coefficients of polynomial, all in [degC] or [ppt]
+      ppol_coefs        ! Coefficients of polynomial, all in [C ~> degC] or [S ~> ppt]
   real :: h_neglect, h_neglect_edge ! Tiny thicknesses [H ~> m or kg m-2]
 
   if (CS%answer_date >= 20190101) then
@@ -1670,6 +1672,45 @@ subroutine TS_PPM_edge_values( CS, S_t, S_b, T_t, T_b, G, GV, tv, h, bdry_extrap
 
 end subroutine TS_PPM_edge_values
 
+!> Calculate edge values (top and bottom of layer) for T and S consistent with a PLM reconstruction
+!! in the vertical direction that uses weighted least squares for the slope.
+subroutine TS_PLM_WLS_edge_values(CS, S_t, S_b, T_t, T_b, G, GV, tv, h)
+  type(ocean_grid_type),   intent(in)    :: G    !< ocean grid structure
+  type(verticalGrid_type), intent(in)    :: GV   !< Ocean vertical grid structure
+  type(ALE_CS),            intent(inout) :: CS   !< module control structure
+  real, dimension(SZI_(G),SZJ_(G),SZK_(GV)), &
+                           intent(inout) :: S_t  !< Salinity at the top edge of each layer [S ~> ppt]
+  real, dimension(SZI_(G),SZJ_(G),SZK_(GV)), &
+                           intent(inout) :: S_b  !< Salinity at the bottom edge of each layer [S ~> ppt]
+  real, dimension(SZI_(G),SZJ_(G),SZK_(GV)), &
+                           intent(inout) :: T_t  !< Temperature at the top edge of each layer [C ~> degC]
+  real, dimension(SZI_(G),SZJ_(G),SZK_(GV)), &
+                           intent(inout) :: T_b  !< Temperature at the bottom edge of each layer [C ~> degC]
+  type(thermo_var_ptrs),   intent(in)    :: tv   !< thermodynamics structure
+  real, dimension(SZI_(G),SZJ_(G),SZK_(GV)), &
+                           intent(in)    :: h    !< layer thickness [H ~> m or kg m-2]
+  ! Local variables
+  integer :: i, j, k
+  type(PLM_WLS) :: recon !< A PLM-WLS reconstruction
+
+  call recon%init(GV%ke, h_neglect=GV%H_subroundoff)
+
+  !$OMP parallel do default(shared) firstprivate(recon)
+  do j = G%jsc-1,G%jec+1 ; do i = G%isc-1,G%iec+1
+
+    call recon%reconstruct(h(i,j,:), tv%T(i,j,:))
+    T_t(i,j,:) = recon%ul(:)
+    T_b(i,j,:) = recon%ur(:)
+
+    call recon%reconstruct(h(i,j,:), tv%S(i,j,:))
+    S_t(i,j,:) = recon%ul(:)
+    S_b(i,j,:) = recon%ur(:)
+
+  enddo ; enddo
+
+  call recon%destroy()
+
+end subroutine TS_PLM_WLS_edge_values
 
 !> Initializes regridding for the main ALE algorithm
 subroutine ALE_initRegridding(G, GV, US, max_depth, param_file, mdl, regridCS)
@@ -1794,7 +1835,7 @@ subroutine ALE_initThicknessToCoord( CS, G, GV, h, height_units )
   scale = GV%Z_to_H
   if (present(height_units)) then ; if (height_units) scale = 1.0 ; endif
   do j = G%jsd,G%jed ; do i = G%isd,G%ied
-    h(i,j,:) = scale * getStaticThickness( CS%regridCS, 0., G%bathyT(i,j)+G%Z_ref )
+    h(i,j,:) = scale * getStaticThickness( CS%regridCS, 0., max(G%meanSL(i,j)+G%bathyT(i,j), 0.0) )
   enddo ; enddo
 
 end subroutine ALE_initThicknessToCoord
diff --git a/src/ALE/MOM_hybgen_unmix.F90 b/src/ALE/MOM_hybgen_unmix.F90
index bb6f64c4d7..5d8b8c9c10 100644
--- a/src/ALE/MOM_hybgen_unmix.F90
+++ b/src/ALE/MOM_hybgen_unmix.F90
@@ -214,23 +214,23 @@ subroutine hybgen_unmix(G, GV, US, CS, tv, Reg, ntr, h)
     endif
 
     ! The following block of code is used to trigger z* stretching of the targets heights.
-    if (allocated(tv%SpV_avg)) then  ! This is the fully non-Boussiesq version
+    if (allocated(tv%SpV_avg)) then  ! This is the fully non-Boussinesq version
       dz_tot = 0.0
       do k=1,nk
         dz_tot = dz_tot + GV%H_to_RZ * tv%SpV_avg(i,j,k) * h_col(k)
       enddo
-      if (dz_tot <= CS%min_dilate*(G%bathyT(i,j)+G%Z_ref)) then
+      if (dz_tot <= CS%min_dilate * (G%meanSL(i,j) + G%bathyT(i,j))) then
         dilate = CS%min_dilate
-      elseif (dz_tot >= CS%max_dilate*(G%bathyT(i,j)+G%Z_ref)) then
+      elseif (dz_tot >= CS%max_dilate * (G%meanSL(i,j) + G%bathyT(i,j))) then
         dilate = CS%max_dilate
       else
-        dilate = dz_tot / (G%bathyT(i,j)+G%Z_ref)
+        dilate = dz_tot / (G%meanSL(i,j) + G%bathyT(i,j))
       endif
     else
-      nominalDepth = (G%bathyT(i,j)+G%Z_ref)*GV%Z_to_H
-      if (h_tot <= CS%min_dilate*nominalDepth) then
+      nominalDepth = (G%meanSL(i,j) + G%bathyT(i,j)) * GV%Z_to_H
+      if (h_tot <= CS%min_dilate * nominalDepth) then
         dilate = CS%min_dilate
-      elseif (h_tot >= CS%max_dilate*nominalDepth) then
+      elseif (h_tot >= CS%max_dilate * nominalDepth) then
         dilate = CS%max_dilate
       else
         dilate = h_tot / nominalDepth
diff --git a/src/ALE/MOM_regridding.F90 b/src/ALE/MOM_regridding.F90
index 9f36ae9d89..2564b9a3bf 100644
--- a/src/ALE/MOM_regridding.F90
+++ b/src/ALE/MOM_regridding.F90
@@ -217,7 +217,7 @@ subroutine initialize_regridding(CS, G, GV, US, max_depth, param_file, mdl, &
   integer :: np       ! Number of profiles,    for HYBRID_MAP
   integer :: nceiling ! ceiling  of map index, for HYBRID_MAP
   integer :: nfloor   ! floor    of map index, for HYBRID_MAP
-  real ::    nfrac    ! fraction of map index, for HYBRID_MAP
+  real ::    nfrac    ! fraction of map index, for HYBRID_MAP [nondim]
   character(len=80)  :: string, string2, varName ! Temporary strings
   character(len=40)  :: coord_units, coord_res_param ! Temporary strings
   character(len=MAX_PARAM_LENGTH) :: param_name
@@ -236,8 +236,8 @@ subroutine initialize_regridding(CS, G, GV, US, max_depth, param_file, mdl, &
                         ! maximum_depth is large [m] (not in Z).
   real :: nominalDepth  ! Depth of ocean bottom in thickness units (positive downward) [H ~> m or kg m-2]
   real :: depth_q       ! A depth scale factor [nondim]
-  real :: depth_s       ! The end of the shallow Z regime (m)
-  real :: depth_d       ! The start of the deep Z regime (m)
+  real :: depth_s       ! The end of the shallow Z regime [m]
+  real :: depth_d       ! The start of the deep Z regime [m]
   real :: adaptTimeRatio, adaptZoomCoeff ! Temporary variables for input parameters [nondim]
   real :: adaptBuoyCoeff, adaptAlpha     ! Temporary variables for input parameters [nondim]
   real :: adaptZoom  ! The thickness of the near-surface zooming region with the adaptive coordinate [H ~> m or kg m-2]
@@ -432,8 +432,16 @@ subroutine initialize_regridding(CS, G, GV, US, max_depth, param_file, mdl, &
                    trim(message), units=trim(coord_units))
   elseif (trim(string)=='PARAM') then
     ! Read coordinate resolution (main model = ALE_RESOLUTION)
-    ke = GV%ke ! Use model nk by default
-    allocate(dz(ke))
+    allocate(dz(1001))
+    dz(:) = -1. ! Setting to <0 allows detection of unset elements
+    call get_param(param_file, mdl, coord_res_param, dz, "Scan", units="", do_not_log=.true.)
+    if (dz(1001)>=0.) call MOM_error(FATAL,trim(mdl)//", initialize_regridding: "// &
+        "PARAM specification is limited to 1000 values. Hack the code to use more!")
+    do ke=1,1000 ! Find number of defined levels
+      if (dz(ke+1)<0.) exit
+    enddo
+    deallocate(dz)
+    allocate(dz(ke)) ! Allocate with the correct number of levels, and re-read thicknesses
     call get_param(param_file, mdl, coord_res_param, dz, &
                    trim(message), units=trim(coord_units), fail_if_missing=.true.)
   elseif (index(trim(string),'FILE:')==1) then
@@ -863,7 +871,7 @@ subroutine initialize_regridding(CS, G, GV, US, max_depth, param_file, mdl, &
       endif
       do i=G%isc-1,G%iec+1; do j=G%jsc-1,G%jec+1
         if (G%mask2dT(i,j)>0.) then
-          nominalDepth = (G%bathyT(i,j)+G%Z_ref)*US%Z_to_m
+          nominalDepth = max(G%meanSL(i,j) + G%bathyT(i,j), 0.0) * US%Z_to_m
           if (nominalDepth <= depth_s) then
             do k= 1,n_sigma
               dz_3d(i,j,k) = dz_shallow(k)
@@ -1208,7 +1216,7 @@ subroutine regridding_main( remapCS, CS, G, GV, US, h, tv, h_new, dzInterface, &
                                                                       !! coordinate [H ~> m or kg m-2]
   real, dimension(SZI_(G),SZJ_(G),CS%nk+1),   intent(inout) :: dzInterface !< The change in position of each
                                                                       !! interface [H ~> m or kg m-2]
-  real, dimension(SZI_(G),SZJ_(G)), optional, intent(in   ) :: frac_shelf_h !< Fractional ice shelf coverage [nomdim]
+  real, dimension(SZI_(G),SZJ_(G)), optional, intent(in   ) :: frac_shelf_h !< Fractional ice shelf coverage [nondim]
   logical, dimension(SZI_(G),SZJ_(G),SZK_(GV)), &
                                     optional, intent(out  ) :: PCM_cell !< Use PCM remapping in cells where true
 
@@ -1243,15 +1251,15 @@ subroutine regridding_main( remapCS, CS, G, GV, US, h, tv, h_new, dzInterface, &
       tot_dz(i,j) = tot_dz(i,j) + GV%H_to_RZ * tv%SpV_avg(i,j,k) * h(i,j,k)
     enddo ; enddo ; enddo
     do j=G%jsc-1,G%jec+1 ; do i=G%isc-1,G%iec+1
-      if ((tot_dz(i,j) > 0.0) .and. (G%bathyT(i,j)+G%Z_ref > 0.0)) then
-        nom_depth_H(i,j) = (G%bathyT(i,j)+G%Z_ref) * (tot_h(i,j) / tot_dz(i,j))
+      if (tot_dz(i,j) > 0.0) then
+        nom_depth_H(i,j) = max(G%meanSL(i,j) + G%bathyT(i,j), 0.0) * (tot_h(i,j) / tot_dz(i,j))
       else
         nom_depth_H(i,j) = 0.0
       endif
     enddo ; enddo
   else
     do j=G%jsc-1,G%jec+1 ; do i=G%isc-1,G%iec+1
-      nom_depth_H(i,j) = max((G%bathyT(i,j)+G%Z_ref) * Z_to_H, 0.0)
+      nom_depth_H(i,j) = max(G%meanSL(i,j) + G%bathyT(i,j), 0.0) * Z_to_H
     enddo ; enddo
   endif
 
@@ -2416,7 +2424,7 @@ subroutine setCoordinateResolution_3d( dz_3d, CS, scale )
                                            !! dependent units, such as [m] for a z-coordinate or [kg m-3]
                                            !! for a density coordinate.
   type(regridding_CS), intent(inout) :: CS !< Regridding control structure
-  real,      optional, intent(in)    :: scale !< A scaling factor converting dz to coordRes [m -> Z]
+  real,      optional, intent(in)    :: scale !< A scaling factor converting dz to coordRes [Z m-1 ~> 1]
 
   if (.not.allocated(CS%coordinateResolution_3d)) &
       call MOM_error(FATAL,'setCoordinateResolution_3d: '//&
@@ -2457,7 +2465,7 @@ end subroutine set_target_densities_from_GV
 subroutine set_target_densities_3d( CS, G, scale, rho_int_3d )
   type(regridding_CS),  intent(inout) :: CS    !< Regridding control structure
   type(ocean_grid_type),intent(in)    :: G     !< Ocean grid structure
-  real,                 intent(in)    :: scale !< A scaling factor converting densities [kg m-3 -> R]
+  real,                 intent(in)    :: scale !< A scaling factor converting densities [R m3 kg-1 ~> 1]
   real, dimension(SZI_(G),SZJ_(G),CS%nk+1), intent(in) :: rho_int_3d !< Interface densities [kg m-3]
 
   if (.not.allocated(CS%target_density_3d)) &
diff --git a/src/ALE/MOM_remapping.F90 b/src/ALE/MOM_remapping.F90
index c47ab73b77..36336f8823 100644
--- a/src/ALE/MOM_remapping.F90
+++ b/src/ALE/MOM_remapping.F90
@@ -35,6 +35,7 @@ module MOM_remapping
 use Recon1d_EPPM_CWK, only : EPPM_CWK
 use Recon1d_PPM_H4_2019, only : PPM_H4_2019
 use Recon1d_PPM_H4_2018, only : PPM_H4_2018
+use Recon1d_PLM_WLS, only : PLM_WLS
 
 implicit none ; private
 
@@ -1792,6 +1793,9 @@ subroutine setReconstructionType(string,CS)
     case ("C_PPM_H4_2018")
       allocate( PPM_H4_2018 :: CS%reconstruction )
       CS%remapping_scheme = REMAPPING_VIA_CLASS
+    case ("C_PLM_WLS")
+      allocate( PLM_WLS :: CS%reconstruction )
+      CS%remapping_scheme = REMAPPING_VIA_CLASS
     case default
       call MOM_error(FATAL, "setReconstructionType: "//&
        "Unrecognized choice for REMAPPING_SCHEME ("//trim(string)//").")
@@ -2111,6 +2115,7 @@ logical function remapping_unit_tests(verbose, num_comp_samp)
   type(PPM_hybgen) :: PPM_hybgen
   type(PPM_CWK) :: PPM_CWK
   type(EPPM_CWK) :: EPPM_CWK
+  type(PLM_WLS) :: PLM_WLS
 
   call test%set( verbose=verbose ) ! Sets the verbosity flag in test
 ! call test%set( stop_instantly=.true. ) ! While debugging
@@ -2740,6 +2745,7 @@ logical function remapping_unit_tests(verbose, num_comp_samp)
   call test%test( PPM_CW%unit_tests(verbose, test%stdout, test%stderr), 'PPM_CW unit test')
   call test%test( PPM_CWK%unit_tests(verbose, test%stdout, test%stderr), 'PPM_CWK unit test')
   call test%test( EPPM_CWK%unit_tests(verbose, test%stdout, test%stderr), 'EPPM_CWK unit test')
+  call test%test( PLM_WLS%unit_tests(verbose, test%stdout, test%stderr), 'PLM_WLS unit test')
 
   ! Randomized, brute force tests
   ntests = 3000
@@ -2769,6 +2775,7 @@ logical function remapping_unit_tests(verbose, num_comp_samp)
   call test_recon_consistency(test, 'C_PPM_CW', n0, ntests, h_neglect)
   call test_recon_consistency(test, 'C_PPM_CWK', n0, ntests, h_neglect)
   call test_recon_consistency(test, 'C_EPPM_CWK', n0, ntests, h_neglect)
+  call test_recon_consistency(test, 'C_PLM_WLS', n0, ntests, h_neglect)
 
   call test_preserve_uniform(test, 'PCM', n0, ntests, h_neglect)
   call test_preserve_uniform(test, 'C_PCM', n0, ntests, h_neglect)
@@ -2795,6 +2802,7 @@ logical function remapping_unit_tests(verbose, num_comp_samp)
   call test_preserve_uniform(test, 'C_PPM_CW', n0, ntests, h_neglect)
   call test_preserve_uniform(test, 'C_PPM_CWK', n0, ntests, h_neglect)
   call test_preserve_uniform(test, 'C_EPPM_CWK', n0, ntests, h_neglect)
+  call test_preserve_uniform(test, 'C_PLM_WLS', n0, ntests, h_neglect)
 
   call test_unchanged_grid(test, 'C_PCM', n0, ntests, h_neglect)
   call test_unchanged_grid(test, 'C_PLM_CW', n0, ntests, h_neglect)
@@ -2806,6 +2814,7 @@ logical function remapping_unit_tests(verbose, num_comp_samp)
   call test_unchanged_grid(test, 'C_PPM_CW', n0, ntests, h_neglect)
   call test_unchanged_grid(test, 'C_PPM_CWK', n0, ntests, h_neglect)
   call test_unchanged_grid(test, 'C_EPPM_CWK', n0, ntests, h_neglect)
+  call test_unchanged_grid(test, 'C_PLM_WLS', n0, ntests, h_neglect)
 
   ! Check that remapping to the exact same grid leaves values unchanged
   allocate( h0(8), u0(8) )
diff --git a/src/ALE/Recon1d_PLM_WLS.F90 b/src/ALE/Recon1d_PLM_WLS.F90
new file mode 100644
index 0000000000..fa38c782aa
--- /dev/null
+++ b/src/ALE/Recon1d_PLM_WLS.F90
@@ -0,0 +1,460 @@
+!> Piecewise Linear Method using Weighted Conservative Least Squares 1D reconstruction
+module Recon1d_PLM_WLS
+
+! This file is part of MOM6. See LICENSE.md for the license.
+
+use Recon1d_type, only : Recon1d, testing
+
+implicit none ; private
+
+public PLM_WLS, testing
+
+!> PLM reconstruction using Weighted Least Squares constrained to conserve for central cell
+!!
+!! The source for the methods ultimately used by this class are:
+!! - init()                    *locally defined
+!! - reconstruct()             *locally defined
+!! - average()                 *locally defined
+!! - f()                       *locally defined
+!! - dfdx()                    *locally defined
+!! - check_reconstruction()    *locally defined
+!! - unit_tests()              *locally defined
+!! - destroy()                 *locally defined
+!! - remap_to_sub_grid()    -> recon1d_type.remap_to_sub_grid()
+!! - init_parent()          -> init()
+!! - reconstruct_parent()   -> reconstruct()
+type, extends (Recon1d) :: PLM_WLS
+
+  real, allocatable :: ul(:) !< Left edge value [A]
+  real, allocatable :: ur(:) !< Right edge value [A]
+  real, allocatable, private :: slp(:) !< Difference across cell, ur - ul [A].
+                              !! This is redundant with ul and ur and not used
+                              !! in any evaluations, but is needed for testing.
+
+contains
+  !> Implementation of the PLM_WLS initialization
+  procedure :: init => init
+  !> Implementation of the PLM_WLS reconstruction
+  procedure :: reconstruct => reconstruct
+  !> Implementation of the PLM_WLS average over an interval [A]
+  procedure :: average => average
+  !> Implementation of evaluating the PLM_WLS reconstruction at a point [A]
+  procedure :: f => f
+  !> Implementation of the derivative of the PLM_WLS reconstruction at a point [A]
+  procedure :: dfdx => dfdx
+  !> Implementation of deallocation for PLM_WLS
+  procedure :: destroy => destroy
+  !> Implementation of check reconstruction for the PLM_WLS reconstruction
+  procedure :: check_reconstruction => check_reconstruction
+  !> Implementation of unit tests for the PLM_WLS reconstruction
+  procedure :: unit_tests => unit_tests
+
+  !> Duplicate interface to init()
+  procedure :: init_parent => init
+  !> Duplicate interface to reconstruct()
+  procedure :: reconstruct_parent => reconstruct
+
+end type PLM_WLS
+
+contains
+
+!> Initialize a 1D PLM reconstruction for n cells
+subroutine init(this, n, h_neglect, check)
+  class(PLM_WLS),    intent(out) :: this      !< This reconstruction
+  integer,           intent(in)  :: n         !< Number of cells in this column
+  real, optional,    intent(in)  :: h_neglect !< A negligibly small width used in cell reconstructions [H]
+  logical, optional, intent(in)  :: check     !< If true, enable some consistency checking
+
+  this%n = n
+
+  allocate( this%u_mean(n) )
+  allocate( this%ul(n) )
+  allocate( this%ur(n) )
+  allocate( this%slp(n) )
+
+  this%h_neglect = tiny( this%u_mean(1) )
+  if (present(h_neglect)) this%h_neglect = h_neglect
+  this%check = .false.
+  if (present(check)) this%check = check
+
+end subroutine init
+
+!> Calculate a 1D PLM_WLS reconstruction based on h(:) and u(:)
+subroutine reconstruct(this, h, u)
+  class(PLM_WLS), intent(inout) :: this !< This reconstruction
+  real,           intent(in)    :: h(*) !< Grid spacing (thickness) [typically H]
+  real,           intent(in)    :: u(*) !< Cell mean values [A]
+  ! Local variables
+  real :: slp ! The PLM slopes (difference across cell) [A]
+  real :: u_l, u_r, u_c ! Left, right, and center values [A]
+  real :: h_l, h_c, h_r ! Thickness of left, center and right cells [H]
+  real :: h_l0, h_r0 ! Thickness of left and right cells with h_neglect added [H]
+  real :: hx2l, hx2r ! Contributions to denominator, <h x^2> [H3]
+  real :: hxyl, hxyr ! Contributions to numerator, <h x y> [H2 A]
+  integer :: n, km1, k, kp1
+
+  n = this%n
+
+  ! Loop over all cells
+  do k = 1, n
+    km1 = max(1, k-1)
+    kp1 = min(n, k+1)
+    u_l = u(km1)
+    u_c = u(k)
+    u_r = u(kp1)
+
+    h_l = h(km1) * real( k - km1 ) ! This zeroes h_l at k==1
+    h_c = h(k)
+    h_r = h(kp1) * real( kp1 - k ) ! This zeroes h_r at k==n
+
+    ! This is the slope that minimizes the error
+    !  sum_l={-1,1} h(k+l) * [ u(k+l) - u(k) + slp * ( z(k+l) - z(k) ) ]
+    ! i.e. volume weighted least squares
+    h_l0 = h_l + this%h_neglect
+    h_r0 = h_r + this%h_neglect
+    hxyl = ( h_l * ( h_c + h_l ) ) * ( u_c - u_l )
+    hxyr = ( h_r * ( h_c + h_r ) ) * ( u_r - u_c )
+    hx2l = h_l0 * ( h_c + h_l0 )**2
+    hx2r = h_r0 * ( h_c + h_r0 )**2
+    slp = 2. * h_c * ( hxyr + hxyl ) / ( hx2l + hx2r )
+
+    ! Mean value
+    this%u_mean(k) = u_c
+
+    ! Left edge
+    this%ul(k) = u_c - 0.5 * slp
+
+    ! Right edge
+    this%ur(k) = u_c + 0.5 * slp
+
+    ! Store slope
+    this%slp(k) = slp
+  enddo
+
+end subroutine reconstruct
+
+!> Value of PLM_WLS reconstruction at a point in cell k [A]
+real function f(this, k, x)
+  class(PLM_WLS), intent(in) :: this !< This reconstruction
+  integer,        intent(in) :: k    !< Cell number
+  real,           intent(in) :: x    !< Non-dimensional position within element [nondim]
+  real :: du ! Difference across cell [A]
+
+  du = this%ur(k) - this%ul(k)
+
+  ! This expression might be used beyond the element to evaluate
+  ! LS errors. In other PLM implementations x is bounded to the
+  ! element and the expressions are constructed to not exceed
+  ! bounds. There are no such constraints for PLM_WLS.
+  f = this%u_mean(k) + du * ( x - 0.5)
+  !f = this%u_mean(k) + this%slp(k) * ( x - 0.5)
+
+end function f
+
+!> Derivative of PLM_WLS reconstruction at a point in cell k [A]
+real function dfdx(this, k, x)
+  class(PLM_WLS), intent(in) :: this !< This reconstruction
+  integer,        intent(in) :: k    !< Cell number
+  real,           intent(in) :: x    !< Non-dimensional position within element [nondim]
+
+  dfdx = this%ur(k) - this%ul(k)
+
+end function dfdx
+
+!> Average between xa and xb for cell k of a 1D PLM reconstruction [A]
+real function average(this, k, xa, xb)
+  class(PLM_WLS), intent(in) :: this !< This reconstruction
+  integer,        intent(in) :: k    !< Cell number
+  real,           intent(in) :: xa   !< Start of averaging interval on element (0 to 1)
+  real,           intent(in) :: xb   !< End of averaging interval on element (0 to 1)
+  real :: xmab ! Mid-point between xa and xb (0 to 1)
+  real :: u_a, u_b ! Values at xa and xb [A]
+
+  ! Mid-point between xa and xb
+  xmab = 0.5 * ( xa + xb )
+
+  ! This expression for u_a can overshoot u_r but is good for xmab<<1
+  u_a = this%ul(k) + ( this%ur(k)  - this%ul(k) ) * xmab
+  ! This expression for u_b can overshoot u_l but is good for 1-xmab<<1
+  u_b = this%ur(k) + ( this%ul(k)  - this%ur(k) ) * ( 1. - xmab )
+
+  ! Since u_a and u_b are both bounded, this will perserve uniformity but will the
+  ! sum be bounded? Emperically it seems to work...
+  average = 0.5 * ( u_a + u_b )
+
+end function average
+
+!> Deallocate the PLM reconstruction
+subroutine destroy(this)
+  class(PLM_WLS), intent(inout) :: this !< This reconstruction
+
+  deallocate( this%u_mean, this%ul, this%ur )
+
+end subroutine destroy
+
+!> Checks the PLM_WLS reconstruction for consistency
+logical function check_reconstruction(this, h, u)
+  class(PLM_WLS), intent(in) :: this !< This reconstruction
+  real,           intent(in) :: h(*) !< Grid spacing (thickness) [typically H]
+  real,           intent(in) :: u(*) !< Cell mean values [A]
+  ! Local variables
+  integer :: k
+  real :: slp ! Cell slope [A]
+  type(PLM_WLS) :: perturbed !< A perturbed reconstruction
+  real :: u_l, u_r, u_c ! Left, right, and center values [A]
+  real :: h_l, h_c, h_r ! Thickness of left, center and right cells [H]
+  real :: h_l0, h_r0, h_c0 ! Thickness of left, right, center cells with h_neglect added [H]
+  real :: x_l, x_r ! Positions of left and right cells [H]
+  real :: hx2l, hx2r ! Contributions to denominator, <h x^2> [H3]
+  real :: hxyl, hxyr ! Contributions to numerator, <h x y> [H2 A]
+  real :: hy2l, hy2r ! Contributions to error, <h y^2> [H3]
+  real :: y_l, y_r ! Left, right, value differencess [A]
+  real :: b_h, bp_h ! slp / h_c [A H-1]
+  integer :: km1, kp1
+
+  check_reconstruction = .false.
+
+  do k = 1, this%n
+    if ( abs( this%u_mean(k) - u(k) ) > 0. ) check_reconstruction = .true.
+  enddo
+
+  ! Check the cell reconstruction is monotonic within each cell (it should be as a straight line)
+  do k = 1, this%n
+    if ( ( this%u_mean(k) - this%ul(k) ) * ( this%ur(k) - this%u_mean(k) ) < 0. ) check_reconstruction = .true.
+  enddo
+
+  ! Check the cell is a straight line (to within machine precision)
+  do k = 1, this%n
+    if ( abs(2. * this%u_mean(k) - ( this%ul(k) + this%ur(k) )) > epsilon(this%u_mean(1)) * &
+         max(abs(2. * this%u_mean(k)), abs(this%ul(k)), abs(this%ur(k))) ) check_reconstruction = .true.
+  enddo
+
+  ! Create a perturbable reconstruction
+  call perturbed%init( this%n, h_neglect=this%h_neglect )
+  call perturbed%reconstruct( h, u ) ! Should reproduce "this"
+  ! Check the copy is identical
+  do k = 1, this%n
+    if ( abs( perturbed%u_mean(k) - this%u_mean(k) ) > 0. ) check_reconstruction = .true.
+    if ( abs( perturbed%ul(k) - this%ul(k) ) > 0. ) check_reconstruction = .true.
+    if ( abs( perturbed%ur(k) - this%ur(k) ) > 0. ) check_reconstruction = .true.
+    if ( abs( perturbed%slp(k) - this%slp(k) ) > 0. ) check_reconstruction = .true.
+  enddo
+  ! Now perturb the slope. The local error should not decrease.
+  do k = 1, this%n
+    slp = this%slp(k) * ( 1.0 + 1. * epsilon(slp) )
+    perturbed%slp(k) = slp
+    perturbed%ul(k) = u(k) - 0.5 * slp
+    perturbed%ur(k) = u(k) + 0.5 * slp
+    if ( LS_error(perturbed, k, h, u) < LS_error(this, k, h, u) ) check_reconstruction = .true.
+
+    slp = this%slp(k) * ( 1.0 - 1. * epsilon(slp) )
+    perturbed%slp(k) = slp
+    perturbed%ul(k) = u(k) - 0.5 * slp
+    perturbed%ur(k) = u(k) + 0.5 * slp
+    if ( LS_error(perturbed, k, h, u) < LS_error(this, k, h, u) ) check_reconstruction = .true.
+  enddo
+
+end function check_reconstruction
+
+!> Returns local least squares error for a particular cell
+!!
+!! Note that this is the error relative to the minimum of the loss function so that at the
+!! true solution this function returns zero. See module documentation.
+real function LS_error(this, k, h, u)
+  type(PLM_WLS), intent(in) :: this !< This reconstruction
+  integer,        intent(in) :: k    !< Cell number
+  real,           intent(in) :: h(*) !< Grid spacing (thickness) [typically H]
+  real,           intent(in) :: u(*) !< Cell mean values [A]
+  ! Local variables
+  real :: u_l, u_r, u_c ! Left, right, and center values [A]
+  real :: h_l, h_c, h_r ! Thickness of left, center and right cells [H]
+  real :: h_l0, h_r0, hc0 ! Thickness of left, right, center cells with h_neglect added [H]
+  real :: hx2l, hx2r ! Contributions to denominator, <h x^2> [H3]
+  real :: hxyl, hxyr ! Contributions to numerator, <h x y> [H2 A]
+  integer :: km1, kp1
+
+  km1 = max(1, k-1)
+  kp1 = min(this%n, k+1)
+  u_l = u(km1)
+  u_c = u(k)
+  u_r = u(kp1)
+
+  h_l = h(km1) * real( k - km1 ) ! This zeroes h_l at k==1
+  h_r = h(kp1) * real( kp1 - k ) ! This zeroes h_r at k==n
+  h_c = h(k)
+  hc0 = h_c + this%h_neglect
+
+  h_l0 = h_l + this%h_neglect
+  h_r0 = h_r + this%h_neglect
+  hxyl = ( h_l * 0.5 * ( h_c + h_l ) ) * ( u_c - u_l )
+  hxyr = ( h_r * 0.5 * ( h_c + h_r ) ) * ( u_r - u_c )
+  hx2l = h_l0 * 0.25 * ( h_c + h_l0 )**2
+  hx2r = h_r0 * 0.25 * ( h_c + h_r0 )**2
+  LS_error = h_c * ( ( hx2l + hx2r ) * this%slp(k) - h(k) * ( hxyl + hxyr ) )**2
+  LS_error = LS_error / ( hc0 * ( hx2l + hx2r ) )
+end function LS_error
+
+!> Runs PLM_WLS reconstruction unit tests and returns True for any fails, False otherwise
+logical function unit_tests(this, verbose, stdout, stderr)
+  class(PLM_WLS), intent(inout) :: this    !< This reconstruction
+  logical,        intent(in)    :: verbose !< True, if verbose
+  integer,        intent(in)    :: stdout  !< I/O channel for stdout
+  integer,        intent(in)    :: stderr  !< I/O channel for stderr
+  ! Local variables
+  real, allocatable :: ul(:), ur(:), um(:) ! test values [A]
+  real, allocatable :: ull(:), urr(:) ! test values [A]
+  type(testing) :: test ! convenience functions
+  integer :: k
+
+  call test%set( stdout=stdout ) ! Sets the stdout channel in test
+  call test%set( stderr=stderr ) ! Sets the stderr channel in test
+  call test%set( verbose=verbose ) ! Sets the verbosity flag in test
+
+  call this%init(3, h_neglect=1.e-20)
+  call test%test( this%n /= 3, "Setting number of levels")
+  allocate( um(3), ul(3), ur(3), ull(3), urr(3) )
+
+  call this%reconstruct( (/1.,1.,1./), (/-1.,0.,2./) )
+  call test%real_arr(3, this%slp, (/1.,1.5,2./), "(1,1,1)(-1,0,2) slope")
+
+  do k = 1, 3
+    um(k) = LS_error(this, k, (/1.,1.,1./), (/-1.,0.,2./) )
+  enddo
+  call test%real_arr(3, um, (/0.,0.,0./), "(1,1,1)(-1,0,2) LS' rel error")
+
+  call this%reconstruct( (/0.,1.,1./), (/-1.,0.,2./) )
+  call test%real_arr(3, this%slp, (/0.,2.,2./), "(0,1,1)(-1,0,2) slope")
+
+  do k = 1, 3
+    um(k) = LS_error(this, k, (/0.,1.,1./), (/-1.,0.,2./) )
+  enddo
+  call test%real_arr(3, um, (/0.,0.,0./), "(0,1,1)(-1,0,2) LS' rel error")
+
+  call this%reconstruct( (/1.,1.,1./), (/-2.,0.,1./) )
+  call test%real_arr(3, this%slp, (/2.,1.5,1./), "(1,1,1)(-2,0,1) slope")
+
+  call this%reconstruct( (/1.,1.,0./), (/-2.,0.,1./) )
+  call test%real_arr(3, this%slp, (/2.,2.,0./), "(1,1,0)(-2,0,1) slope")
+
+  call this%destroy()
+  call this%init(3) ! Reset to defaults
+
+  ! Straight line data on uniform grid
+  call this%reconstruct( (/2.,2.,2./), (/1.,3.,5./) )
+  call test%real_arr(3, this%u_mean, (/1.,3.,5./), "Straight line data")
+
+  do k = 1, 3
+    ul(k) = this%f(k, 0.)
+    um(k) = this%f(k, 0.5)
+    ur(k) = this%f(k, 1.)
+  enddo
+  call test%real_arr(3, ul, (/0.,2.,4./), "Evaluation on left edge")
+  call test%real_arr(3, um, (/1.,3.,5./), "Evaluation in center")
+  call test%real_arr(3, ur, (/2.,4.,6./), "Evaluation on right edge")
+
+  do k = 1, 3
+    ul(k) = this%dfdx(k, 0.)
+    um(k) = this%dfdx(k, 0.5)
+    ur(k) = this%dfdx(k, 1.)
+  enddo
+  call test%real_arr(3, ul, (/2.,2.,2./), "dfdx on left edge")
+  call test%real_arr(3, um, (/2.,2.,2./), "dfdx in center")
+  call test%real_arr(3, ur, (/2.,2.,2./), "dfdx on right edge")
+
+  do k = 1, 3
+    um(k) = LS_error(this, k, (/2.,2.,2./), (/1.,3.,5./) )
+  enddo
+  call test%real_arr(3, um, (/0.,0.,0./), "Rel error is 0")
+
+  do k = 1, 3
+    um(k) = this%average(k, 0.5, 0.75) ! Average from x=0.5 to 0.75 in each cell
+  enddo
+  call test%real_arr(3, um, (/1.25,3.25,5.25/), "Return interval average")
+
+  call this%destroy()
+  deallocate( um, ul, ur, ull, urr )
+
+  allocate( um(4), ul(4), ur(4) )
+  call this%init(4)
+
+  deallocate( um, ul, ur )
+
+  unit_tests = test%summarize("PLM_WLS:unit_tests")
+
+end function unit_tests
+
+!> \namespace recon1d_plm_wls
+!!
+!! This implementation of PLM fits the slope using least squares, but retains conservation
+!! for the central cell by passing through the central value.
+!! Cell-wise reconstructions are NOT limited by neighbours.
+!! Thus, this reconstruction does not yield monotonic profiles needed for the general remapping problem.
+!!
+!! The algorithm solves the least squares problem of fitting a straight line through
+!! the neighboring data. The line is constained to pass through the center cell,
+!! \f$ (x_{k}, y_{k}) \f$, so that the construction is conservative. The more general
+!! function \f$ f(x) = a_{k} + b_{k} x \f$ would not conserve for arbitrary data.
+!!
+!! The unknown parameter \f$ b_{k} \f$ in the line
+!! \f[
+!!  f(x) = y_{k} + b_{k} ( x - x_{k} ) / h_{k}
+!! \f]
+!! is fit to neighbors \f$ x_{k-1}, y_{k-1} \f$ and \f$ x_{k+1}, y_{k+1} \f$.
+!!
+!! Denoting \f$ y'_{k+j} = y_{k+j} - y_{k} \f$ and \f$ x'_{k+j} = x_{k+j} - x_{k} \f$
+!! the local error is
+!! \f{align}{
+!!  e_{k+j} &= b_k \frac{ x_{k+j} - x_{k} }{ h_{k} } + y_{k} - y_{k+j} \\\\
+!!          &= b_k \frac{ x'_{k+j} }{ h_{k} } - y'_{k+j}
+!! \;\; . \f}
+!!
+!! We use volume weighting in the loss
+!! \f[
+!!  G(b) = h_{k-1} e_{k-1}^2 + h_{k+1} e_{k+1}^2
+!! \;\; . \f]
+!!
+!! When solving for \f$ b_k \f$, we solve \f$ dG/db = 0 \f$ where
+!! \f{align}{
+!!  dG/db &= 2 h_{k-1} e_{k-1} \frac{ de_{k-1} }{db} + 2 h_{k+1} e_{k+1} \frac{ de_{k+1} }{db} \\\\
+!!        &= 2 h_{k-1} ( b_k \frac{ x'_{k-1} }{ h_{k} } - \frac{ y'_{k-1} ) x'_{k-1} }{ h_{k} } +
+!!           2 h_{k+1} ( b_k \frac{ x'_{k+1} }{ h_{k} } - \frac{ y'_{k+1} ) x'_{k+1} }{ h_{k} } \\\\
+!!        &= 4 b_k \frac{ < h x'^2 > }{ h_{k}^2 } - 4 \frac{ < h x' y' > }{ h_{k} }
+!! \f}
+!! and where \f$ < a > = \frac{1}{2} ( a_{k-1} + a_{k+1} ) \f$.
+!! Thus
+!! \f[
+!!  b_k = \frac{ h_{k} < h x' y' > }{ < h x'^2 > } \;\; .
+!! \f]
+!!
+!! When evaluating the loss, \f$ G \f$, some rearrangement is necessary to reduce truncation
+!! errors. Since
+!! \f{align}{
+!!  e_{k+j}^2 &= \left( b \frac{ x'_{k+j} }{ h_{k} } - y'_{k+j} \right)^2 \\\\
+!!            &= b^2 \frac{ {x'}_{k+j}^2 }{ h_{k}^2 } - 2 b \frac{ x'_{k+j} y'_{k+j} }{ h_{k} } + {y'}_{k+j}^2
+!! \f}
+!! then
+!! \f{align}{
+!!  G(b) &= 2 < h e^2 > \\\\
+!!       &= 2 b^2 \frac{ < h {x'}^2 > }{ h_{k}^2 } - 4 b \frac{ < h x' y' > }{ h_{k} } + 2 < h' {y'}^2 >
+!! \;\; .
+!! \f}
+!!
+!! If we denote the value of b that yields the minimum value as \f$ b^* \f$ then
+!! \f[
+!!  G(b^*) = < h {y'}^2 > - \frac{ < h x' y' >^2 }{ < h {x'}^2 > }
+!! \;\; .
+!! \f]
+!!
+!! Let
+!! \f{align}{
+!!  G''(b) &= G(b) - G(b^*) \\\\
+!!         &= b^2 \frac{ < h {x'}^2 > }{ h_{k}^2 } - 2 b \frac{ < h x' y' > }{ h_{k} }
+!!            + \frac{ < h x' y' > }{ < h {x'}^2 > } \\\\
+!!         &= \frac{ \left( b < h {x'}^2 > - h_{k} < h x' y' > \right)^2 }{ h_{k} < h {x'}^2 > }
+!! \;\; .
+!! \f}
+!! Minimizing \f$ G''(b) \f$ is equivalent to minimizing \f$ G(b) \f$ for the same data.
+!! \f$ G''(b^*)=0 \f$ so evaluation with the last form, in the vicinity of \f$ b^* \f$, avoids
+!! large cancelling terms.
+
+end module Recon1d_PLM_WLS
diff --git a/src/ALE/Recon1d_PPM_CW.F90 b/src/ALE/Recon1d_PPM_CW.F90
index 9523ad46ea..7e25bc3d49 100644
--- a/src/ALE/Recon1d_PPM_CW.F90
+++ b/src/ALE/Recon1d_PPM_CW.F90
@@ -158,7 +158,7 @@ subroutine reconstruct(this, h, u)
     u2 = u(k+1)
     a6 = 3.0 * ( ( u1 - this%ul(k) ) + ( u1 - this%ur(k) ) )
     du = this%ur(k) - this%ul(k)
-    if ( ( u2 - u1 ) * ( u1 - u0 ) <- 0.0 ) then ! Large scale extrema
+    if ( ( u2 - u1 ) * ( u1 - u0 ) <= 0.0 ) then ! Large scale extrema
       this%ul(k) = u1
       this%ur(k) = u1
     elseif ( du * a6 > du * du ) then ! Extrema on right
diff --git a/src/ALE/Recon1d_PPM_CWK.F90 b/src/ALE/Recon1d_PPM_CWK.F90
index a0cbce5877..7e0d613e7a 100644
--- a/src/ALE/Recon1d_PPM_CWK.F90
+++ b/src/ALE/Recon1d_PPM_CWK.F90
@@ -143,7 +143,7 @@ subroutine reconstruct(this, h, u)
     u2 = u(k+1)
     a6 = 3.0 * ( ( u1 - this%ul(k) ) + ( u1 - this%ur(k) ) )
     du = this%ur(k) - this%ul(k)
-    if ( ( u2 - u1 ) * ( u1 - u0 ) <- 0.0 ) then ! Large scale extrema
+    if ( ( u2 - u1 ) * ( u1 - u0 ) <= 0.0 ) then ! Large scale extrema
       this%ul(k) = u1
       this%ur(k) = u1
     elseif ( du * a6 > du * du ) then ! Extrema on right
diff --git a/src/ALE/Recon1d_PPM_hybgen.F90 b/src/ALE/Recon1d_PPM_hybgen.F90
index 2978dd9269..058c0a80dc 100644
--- a/src/ALE/Recon1d_PPM_hybgen.F90
+++ b/src/ALE/Recon1d_PPM_hybgen.F90
@@ -134,7 +134,7 @@ subroutine reconstruct(this, h, u)
     a6 = 3.0 * ( ( u1 - this%ul(k) ) + ( u1 - this%ur(k) ) )
     a6 = 6.0 * u1 - 3.0 * ( this%ul(k) + this%ur(k) )
     du = this%ur(k) - this%ul(k)
-    if ( ( u2 - u1 ) * ( u1 - u0 ) <- 0.0 ) then ! Large scale extrema
+    if ( ( u2 - u1 ) * ( u1 - u0 ) <= 0.0 ) then ! Large scale extrema
       this%ul(k) = u1
       this%ur(k) = u1
     elseif ( du * a6 > du * du ) then ! Extrema on right
diff --git a/src/ALE/Recon1d_type.F90 b/src/ALE/Recon1d_type.F90
index 4411e1288e..c11d880cc8 100644
--- a/src/ALE/Recon1d_type.F90
+++ b/src/ALE/Recon1d_type.F90
@@ -15,7 +15,7 @@ module Recon1d_type
 
   integer :: n = 0 !< Number of cells in column
   real, allocatable, dimension(:) :: u_mean !< Cell mean [A]
-  real :: h_neglect = 0. !< A negligibly small width used in cell reconstructions [same as h, H]
+  real :: h_neglect = 0. !< A negligibly small width used in cell reconstructions in the same units as h [H]
   logical :: check = .false. !< If true, enable some consistency checking
 
   logical :: debug = .false. !< If true, dump info as calculations are made (do not enable)
@@ -80,7 +80,7 @@ end subroutine i_init
   subroutine i_reconstruct(this, h, u)
     import :: Recon1d
     class(Recon1d), intent(inout) :: this !< This reconstruction
-    real,           intent(in)    :: h(*) !< Grid spacing (thickness) [typically H]
+    real,           intent(in)    :: h(*) !< Grid spacing (thickness), typically in [H]
     real,           intent(in)    :: u(*) !< Cell mean values [A]
   end subroutine i_reconstruct
 
@@ -122,7 +122,7 @@ end function i_dfdx
   logical function i_check_reconstruction(this, h, u)
     import :: Recon1d
     class(Recon1d), intent(in) :: this !< This reconstruction
-    real,           intent(in) :: h(*) !< Grid spacing (thickness) [typically H]
+    real,           intent(in) :: h(*) !< Grid spacing (thickness), typically in [H]
     real,           intent(in) :: u(*) !< Cell mean values [A]
   end function i_check_reconstruction
 
@@ -145,7 +145,7 @@ end subroutine i_init_parent
   subroutine i_reconstruct_parent(this, h, u)
     import :: Recon1d
     class(Recon1d), intent(inout) :: this !< This reconstruction
-    real,           intent(in)    :: h(*) !< Grid spacing (thickness) [typically H]
+    real,           intent(in)    :: h(*) !< Grid spacing (thickness), typically in [H]
     real,           intent(in)    :: u(*) !< Cell mean values [A]
   end subroutine i_reconstruct_parent
 
diff --git a/src/ALE/regrid_edge_values.F90 b/src/ALE/regrid_edge_values.F90
index 54cec45cba..e969a94023 100644
--- a/src/ALE/regrid_edge_values.F90
+++ b/src/ALE/regrid_edge_values.F90
@@ -1003,7 +1003,8 @@ subroutine edge_slopes_implicit_h5( N, h, u, edge_slopes, h_neglect, answer_date
   real, dimension(7)    :: x            ! Coordinate system with 0 at edges in the same units as h [H]
   real, parameter       :: C1_12 = 1.0 / 12.0   ! A rational parameter [nondim]
   real, parameter       :: C5_6 = 5.0 / 6.0     ! A rational parameter [nondim]
-  real                  :: dx, xavg     ! Differences and averages of successive values of x [same units as h]
+  real                  :: dx           ! Differences between successive values of x in the same units as h [H]
+  real                  :: xavg         ! Average of successive values of x in the same units as h [H]
   real, dimension(6,6)  :: Asys         ! The matrix that is being inverted for a solution,
                                         ! in units that might vary with the second (j) index as [H^j]
   real, dimension(6)    :: Bsys         ! The right hand side of the system to solve for C in various
diff --git a/src/ALE/regrid_interp.F90 b/src/ALE/regrid_interp.F90
index 6e0be9ebba..03e26ada3c 100644
--- a/src/ALE/regrid_interp.F90
+++ b/src/ALE/regrid_interp.F90
@@ -335,19 +335,19 @@ subroutine build_and_interpolate_grid(CS, densities, n0, h0, x0, target_values,
   integer,               intent(in)    :: n1  !< The number of points on the output grid
   real, dimension(n0),   intent(in)    :: densities !< Input cell densities [R ~> kg m-3]
   real, dimension(n1+1), intent(in)    :: target_values !< Target values of interfaces [R ~> kg m-3]
-  real, dimension(n0),   intent(in)    :: h0  !< Initial cell widths [H]
-  real, dimension(n0+1), intent(in)    :: x0  !< Source interface positions [H]
-  real, dimension(n1),   intent(inout) :: h1  !< Output cell widths [H]
-  real, dimension(n1+1), intent(inout) :: x1  !< Target interface positions [H]
+  real, dimension(n0),   intent(in)    :: h0  !< Initial cell widths usually in [H ~> m or kg m-2] or [Z ~> m]
+  real, dimension(n0+1), intent(in)    :: x0  !< Source interface positions [H ~> m or kg m-2] or [Z ~> m]
+  real, dimension(n1),   intent(inout) :: h1  !< Output cell widths [H ~> m or kg m-2] or [Z ~> m]
+  real, dimension(n1+1), intent(inout) :: x1  !< Target interface positions [H ~> m or kg m-2] or [Z ~> m]
   real,                  intent(in)    :: h_neglect !< A negligibly small width for the
-                                           !! purpose of cell reconstructions [H]
-                                           !! in the same units as h0.
-  real,        optional, intent(in)    :: h_neglect_edge !< A negligibly small width
-                                           !! for the purpose of edge value calculations [H]
-                                           !! in the same units as h0.
+                                           !! purpose of cell reconstructions in the same
+                                           !! units as h0 [H ~> m or kg m-2] or [Z ~> m].
+  real,        optional, intent(in)    :: h_neglect_edge !< A negligibly small width for the
+                                           !! purpose of edge value calculations in the same
+                                           !! units as h0 [H ~> m or kg m-2] or [Z ~> m]
 
   real, dimension(n0,2) :: ppoly0_E   ! Polynomial edge values [R ~> kg m-3]
-  real, dimension(n0,2) :: ppoly0_S   ! Polynomial edge slopes [R H-1]
+  real, dimension(n0,2) :: ppoly0_S   ! Polynomial edge slopes [R H-1 ~> kg m-4 or m-1] or [R Z-1 ~> kg m-4]
   real, dimension(n0,DEGREE_MAX+1) :: ppoly0_C  ! Polynomial interpolant coeficients on the local 0-1 grid [R ~> kg m-3]
   integer :: degree
 
diff --git a/src/core/MOM.F90 b/src/core/MOM.F90
index 71832ba76c..fc5acc1c02 100644
--- a/src/core/MOM.F90
+++ b/src/core/MOM.F90
@@ -1597,13 +1597,11 @@ subroutine step_MOM_thermo(CS, G, GV, US, u, v, h, tv, fluxes, dtdia, &
 
   logical :: debug_redundant ! If true, check redundant values on PE boundaries when debugging.
   logical :: showCallTree
-  type(group_pass_type) :: pass_T_S, pass_T_S_h, pass_uv_T_S_h
+  type(group_pass_type) :: pass_T_S
   integer :: dynamics_stencil  ! The computational stencil for the calculations
                                ! in the dynamic core.
   integer :: halo_sz ! The size of a halo where data must be valid.
-  integer :: i, j, k, is, ie, js, je, nz
 
-  is = G%isc ; ie = G%iec ; js = G%jsc ; je = G%jec ; nz = GV%ke
   showCallTree = callTree_showQuery()
   if (showCallTree) call callTree_enter("step_MOM_thermo(), MOM.F90")
   if (CS%debug) call query_debugging_checks(do_redundant=debug_redundant)
@@ -1764,9 +1762,7 @@ subroutine ALE_regridding_and_remapping(CS, G, GV, US, u, v, h, tv, dtdia, Time_
   logical :: use_ice_shelf ! Needed for selecting the right ALE interface.
   logical :: debug_redundant ! If true, check redundant values on PE boundaries when debugging.
   logical :: showCallTree
-  type(group_pass_type) :: pass_T_S, pass_T_S_h, pass_uv_T_S_h
-  integer :: dynamics_stencil  ! The computational stencil for the calculations
-                               ! in the dynamic core.
+  type(group_pass_type) :: pass_T_S_h
   integer :: i, j, k, is, ie, js, je, nz
 
   is = G%isc ; ie = G%iec ; js = G%jsc ; je = G%jec ; nz = GV%ke
@@ -1929,12 +1925,10 @@ subroutine post_diabatic_halo_updates(CS, G, GV, US, u, v, h, tv)
 
   logical :: debug_redundant ! If true, check redundant values on PE boundaries when debugging.
   logical :: showCallTree
-  type(group_pass_type) :: pass_T_S, pass_T_S_h, pass_uv_T_S_h
+  type(group_pass_type) :: pass_uv_T_S_h
   integer :: dynamics_stencil  ! The computational stencil for the calculations
                                ! in the dynamic core.
-  integer :: i, j, k, is, ie, js, je, nz
 
-  is = G%isc ; ie = G%iec ; js = G%jsc ; je = G%jec ; nz = GV%ke
   showCallTree = callTree_showQuery()
   if (showCallTree) call callTree_enter("post_diabatic_halo_updates, MOM.F90")
   if (CS%debug) call query_debugging_checks(do_redundant=debug_redundant)
@@ -3602,13 +3596,9 @@ subroutine initialize_MOM(Time, Time_init, param_file, dirs, CS, &
   if (associated(CS%sponge_CSp)) &
     call init_sponge_diags(Time, G, GV, US, diag, CS%sponge_CSp)
 
-  if (associated(CS%ALE_sponge_CSp)) &
-    call init_ALE_sponge_diags(Time, G, diag, CS%ALE_sponge_CSp, US)
-
   if (associated(CS%oda_incupd_CSp)) &
     call init_oda_incupd_diags(Time, G, GV, diag, CS%oda_incupd_CSp, US)
 
-
   call tracer_advect_init(Time, G, US, param_file, diag, CS%tracer_adv_CSp)
   call tracer_hor_diff_init(Time, G, GV, US, param_file, diag, CS%tv%eqn_of_state, CS%diabatic_CSp, &
                             CS%tracer_diff_CSp)
@@ -3642,6 +3632,9 @@ subroutine initialize_MOM(Time, Time_init, param_file, dirs, CS, &
              CS%ALE_sponge_CSp, CS%tv)
   if (present(tracer_flow_CSp)) tracer_flow_CSp => CS%tracer_flow_CSp
 
+  if (associated(CS%ALE_sponge_CSp)) &
+    call init_ALE_sponge_diags(Time, G, diag, CS%ALE_sponge_CSp, US)
+
   ! If running in offline tracer mode, initialize the necessary control structure and
   ! parameters
   if (present(offline_tracer_mode)) offline_tracer_mode=CS%offline_tracer_mode
@@ -4286,8 +4279,8 @@ subroutine extract_surface_state(CS, sfc_state_in)
     do j=js,je ; do i=is,ie
       if (G%mask2dT(i,j)>0.) then
         localError = sfc_state%sea_lev(i,j) < -G%bathyT(i,j) - G%Z_ref &
-                .or. sfc_state%sea_lev(i,j) >=  CS%bad_val_ssh_max  &
-                .or. sfc_state%sea_lev(i,j) <= -CS%bad_val_ssh_max  &
+                .or. sfc_state%sea_lev(i,j) >=  CS%bad_val_ssh_max + (G%meanSL(i,j) - G%Z_ref) &
+                .or. sfc_state%sea_lev(i,j) <= -CS%bad_val_ssh_max + (G%meanSL(i,j) - G%Z_ref) &
                 .or. sfc_state%sea_lev(i,j) + G%bathyT(i,j) + G%Z_ref < CS%bad_val_col_thick
         if (use_temperature) localError = localError &
                 .or. sfc_state%SSS(i,j)<0.                        &
diff --git a/src/core/MOM_CoriolisAdv.F90 b/src/core/MOM_CoriolisAdv.F90
index 5495164782..6e491c676c 100644
--- a/src/core/MOM_CoriolisAdv.F90
+++ b/src/core/MOM_CoriolisAdv.F90
@@ -246,9 +246,7 @@ subroutine CorAdCalc(u, v, h, uh, vh, CAu, CAv, OBC, AD, G, GV, US, CS, pbv, Wav
   logical :: Stokes_VF
   real :: u_v, v_u      ! u_v is the u velocity at v point, v_u is the v velocity at u point [L T-1 ~> m s-1]
   real :: q_v, q_u      ! PV at the u and v points [H-1 T-1 ~> m-1 s-1 or m2 kg-1 s-1]
-  real :: h_v, h_u      ! h_v is the thickness at v point, h_u is the thickness at u point [H ~> m or kg m-2]
-  integer :: seventh_order, fifth_order, third_order, second_order ! Order of accuracy for the WENO calculations
-  real :: psi           ! Ratio of PV gradient for the Koren limiter [nondim]
+  integer :: seventh_order, fifth_order, third_order ! Order of accuracy for the WENO calculations
   real :: u_q8(8) ! Eight-point zonal velocity at WENO stencils [L T-1 ~> m s-1]
   real :: u_q6(6) ! Six-point zonal velocity at WENO stencils [L T-1 ~> m s-1]
   real :: u_q4(4) ! Four-point zonal velocity at WENO stencils [L T-1 ~> m s-1]
@@ -676,7 +674,7 @@ subroutine CorAdCalc(u, v, h, uh, vh, CAu, CAv, OBC, AD, G, GV, US, CS, pbv, Wav
     endif
 
     ! Calculate KE and the gradient of KE
-    call gradKE(u, v, h, KE, KEx, KEy, k, OBC, G, GV, US, CS)
+    call gradKE(u(:,:,k), v(:,:,k), h(:,:,k), KE, KEx, KEy, G, GV, US, CS)
 
     ! Calculate the tendencies of zonal velocity due to the Coriolis
     ! force and momentum advection.  On a Cartesian grid, this is
@@ -1231,22 +1229,20 @@ subroutine CorAdCalc(u, v, h, uh, vh, CAu, CAv, OBC, AD, G, GV, US, CS, pbv, Wav
 end subroutine CorAdCalc
 
 
-!> Calculates the acceleration due to the gradient of kinetic energy.
-subroutine gradKE(u, v, h, KE, KEx, KEy, k, OBC, G, GV, US, CS)
-  type(ocean_grid_type),                      intent(in)  :: G   !< Ocean grid structure
-  type(verticalGrid_type),                    intent(in)  :: GV  !< Vertical grid structure
-  real, dimension(SZIB_(G),SZJ_(G),SZK_(GV)), intent(in)  :: u   !< Zonal velocity [L T-1 ~> m s-1]
-  real, dimension(SZI_(G),SZJB_(G),SZK_(GV)), intent(in)  :: v   !< Meridional velocity [L T-1 ~> m s-1]
-  real, dimension(SZI_(G),SZJ_(G),SZK_(GV)),  intent(in)  :: h   !< Layer thickness [H ~> m or kg m-2]
-  real, dimension(SZI_(G) ,SZJ_(G) ),         intent(out) :: KE  !< Kinetic energy per unit mass [L2 T-2 ~> m2 s-2]
-  real, dimension(SZIB_(G),SZJ_(G) ),         intent(out) :: KEx !< Zonal acceleration due to kinetic
-                                                                 !! energy gradient [L T-2 ~> m s-2]
-  real, dimension(SZI_(G) ,SZJB_(G)),         intent(out) :: KEy !< Meridional acceleration due to kinetic
-                                                                 !! energy gradient [L T-2 ~> m s-2]
-  integer,                                    intent(in)  :: k   !< Layer number to calculate for
-  type(ocean_OBC_type),                       pointer     :: OBC !< Open boundary control structure
-  type(unit_scale_type),                      intent(in)  :: US  !< A dimensional unit scaling type
-  type(CoriolisAdv_CS),                       intent(in)  :: CS  !< Control structure for MOM_CoriolisAdv
+!> Calculates the acceleration due to the gradient of kinetic energy in one layer.
+subroutine gradKE(u, v, h, KE, KEx, KEy, G, GV, US, CS)
+  type(ocean_grid_type),             intent(in)  :: G   !< Ocean grid structure
+  type(verticalGrid_type),           intent(in)  :: GV  !< Vertical grid structure
+  real, dimension(SZIB_(G),SZJ_(G)), intent(in)  :: u   !< Zonal velocity [L T-1 ~> m s-1]
+  real, dimension(SZI_(G),SZJB_(G)), intent(in)  :: v   !< Meridional velocity [L T-1 ~> m s-1]
+  real, dimension(SZI_(G),SZJ_(G)),  intent(in)  :: h   !< Layer thickness [H ~> m or kg m-2]
+  real, dimension(SZI_(G),SZJ_(G)),  intent(out) :: KE  !< Kinetic energy per unit mass [L2 T-2 ~> m2 s-2]
+  real, dimension(SZIB_(G),SZJ_(G)), intent(out) :: KEx !< Zonal acceleration due to kinetic
+                                                        !! energy gradient [L T-2 ~> m s-2]
+  real, dimension(SZI_(G),SZJB_(G)), intent(out) :: KEy !< Meridional acceleration due to kinetic
+                                                        !! energy gradient [L T-2 ~> m s-2]
+  type(unit_scale_type),             intent(in)  :: US  !< A dimensional unit scaling type
+  type(CoriolisAdv_CS),              intent(in)  :: CS  !< Control structure for MOM_CoriolisAdv
   ! Local variables
   real :: um, up, vm, vp         ! Temporary variables [L T-1 ~> m s-1].
   real :: um2, up2, vm2, vp2     ! Temporary variables [L2 T-2 ~> m2 s-2].
@@ -1265,29 +1261,29 @@ subroutine gradKE(u, v, h, KE, KEx, KEy, k, OBC, G, GV, US, CS)
     ! identified in Arakawa & Lamb 1982 as important for KE conservation.  It
     ! also includes the possibility of partially-blocked tracer cell faces.
     do j=Jsq,Jeq+1 ; do i=Isq,Ieq+1
-      KE(i,j) = ( ( (G%areaCu( I ,j)*(u( I ,j,k)*u( I ,j,k))) + &
-                    (G%areaCu(I-1,j)*(u(I-1,j,k)*u(I-1,j,k))) ) + &
-                  ( (G%areaCv(i, J )*(v(i, J ,k)*v(i, J ,k))) + &
-                    (G%areaCv(i,J-1)*(v(i,J-1,k)*v(i,J-1,k))) ) )*0.25*G%IareaT(i,j)
+      KE(i,j) = ( ( (G%areaCu( I ,j)*(u( I ,j)*u( I ,j))) + &
+                    (G%areaCu(I-1,j)*(u(I-1,j)*u(I-1,j))) ) + &
+                  ( (G%areaCv(i, J )*(v(i, J )*v(i, J ))) + &
+                    (G%areaCv(i,J-1)*(v(i,J-1)*v(i,J-1))) ) )*0.25*G%IareaT(i,j)
     enddo ; enddo
   elseif (CS%KE_Scheme == KE_SIMPLE_GUDONOV) then
     ! The following discretization of KE is based on the one-dimensional Gudonov
     ! scheme which does not take into account any geometric factors
     do j=Jsq,Jeq+1 ; do i=Isq,Ieq+1
-      up = 0.5*( u(I-1,j,k) + ABS( u(I-1,j,k) ) ) ; up2 = up*up
-      um = 0.5*( u( I ,j,k) - ABS( u( I ,j,k) ) ) ; um2 = um*um
-      vp = 0.5*( v(i,J-1,k) + ABS( v(i,J-1,k) ) ) ; vp2 = vp*vp
-      vm = 0.5*( v(i, J ,k) - ABS( v(i, J ,k) ) ) ; vm2 = vm*vm
+      up = 0.5*( u(I-1,j) + ABS( u(I-1,j) ) ) ; up2 = up*up
+      um = 0.5*( u( I ,j) - ABS( u( I ,j) ) ) ; um2 = um*um
+      vp = 0.5*( v(i,J-1) + ABS( v(i,J-1) ) ) ; vp2 = vp*vp
+      vm = 0.5*( v(i, J ) - ABS( v(i, J ) ) ) ; vm2 = vm*vm
       KE(i,j) = ( max(up2,um2) + max(vp2,vm2) ) *0.5
     enddo ; enddo
   elseif (CS%KE_Scheme == KE_GUDONOV) then
     ! The following discretization of KE is based on the one-dimensional Gudonov
     ! scheme but has been adapted to take horizontal grid factors into account
     do j=Jsq,Jeq+1 ; do i=Isq,Ieq+1
-      up = 0.5*( u(I-1,j,k) + ABS( u(I-1,j,k) ) ) ; up2a = up*up*G%areaCu(I-1,j)
-      um = 0.5*( u( I ,j,k) - ABS( u( I ,j,k) ) ) ; um2a = um*um*G%areaCu( I ,j)
-      vp = 0.5*( v(i,J-1,k) + ABS( v(i,J-1,k) ) ) ; vp2a = vp*vp*G%areaCv(i,J-1)
-      vm = 0.5*( v(i, J ,k) - ABS( v(i, J ,k) ) ) ; vm2a = vm*vm*G%areaCv(i, J )
+      up = 0.5*( u(I-1,j) + ABS( u(I-1,j) ) ) ; up2a = up*up*G%areaCu(I-1,j)
+      um = 0.5*( u( I ,j) - ABS( u( I ,j) ) ) ; um2a = um*um*G%areaCu( I ,j)
+      vp = 0.5*( v(i,J-1) + ABS( v(i,J-1) ) ) ; vp2a = vp*vp*G%areaCv(i,J-1)
+      vm = 0.5*( v(i, J ) - ABS( v(i, J ) ) ) ; vm2a = vm*vm*G%areaCv(i, J )
       KE(i,j) = ( max(um2a,up2a) + max(vm2a,vp2a) )*0.5*G%IareaT(i,j)
     enddo ; enddo
   elseif (CS%KE_Scheme == KE_UP3) then
@@ -1300,14 +1296,14 @@ subroutine gradKE(u, v, h, KE, KEx, KEy, k, OBC, G, GV, US, CS)
                        G%mask2dCu(I,j) * G%mask2dCu(I+1,j))
 
         if (third_order_u == 1) then
-          up = (7.0 * (u(I-1,j,k) + u(I,j,k)) - (u(I-2,j,k) + u(I+1,j,k))) * C1_12
-          call UP3_Koren_limiter_reconstruction(u(I-2:I+1,j,k), up, um)
+          up = (7.0 * (u(I-1,j) + u(I,j)) - (u(I-2,j) + u(I+1,j))) * C1_12
+          call UP3_Koren_limiter_reconstruction(u(I-2:I+1,j), up, um)
         else
-          up = (u(I-1,j,k) + u(I,j,k))*0.5
+          up = (u(I-1,j) + u(I,j))*0.5
           if (up>0.) then
-            um = u(I-1,j,k)
+            um = u(I-1,j)
           elseif (up<0.) then
-            um = u(I,j,k)
+            um = u(I,j)
           else
             um = up
           endif
@@ -1316,14 +1312,14 @@ subroutine gradKE(u, v, h, KE, KEx, KEy, k, OBC, G, GV, US, CS)
         third_order_v = (G%mask2dCv(i,J-2) * G%mask2dCv(i,J-1)* &
                        G%mask2dCv(i,J) * G%mask2dCv(i,J+1))
         if (third_order_v ==1) then
-          vp = (7.0 * (v(i,J-1,k) + v(i,J,k)) - (v(i,J-2,k) + v(i,J+1,k))) * C1_12
-          call UP3_Koren_limiter_reconstruction(v(i,J-2:J+1,k), vp, vm)
+          vp = (7.0 * (v(i,J-1) + v(i,J)) - (v(i,J-2) + v(i,J+1))) * C1_12
+          call UP3_Koren_limiter_reconstruction(v(i,J-2:J+1), vp, vm)
         else
-          vp = (v(i,J-1,k) + v(i,J,k))*0.5
+          vp = (v(i,J-1) + v(i,J))*0.5
           if (vp>0.) then
-            vm = v(i,J-1,k)
+            vm = v(i,J-1)
           elseif (vp<0.) then
-            vm = v(i,J,k)
+            vm = v(i,J)
           else
             vm = vp
           endif
@@ -1338,14 +1334,14 @@ subroutine gradKE(u, v, h, KE, KEx, KEy, k, OBC, G, GV, US, CS)
                        G%mask2dCu(I,j) * G%mask2dCu(I+1,j))
 
         if (third_order_u == 1) then
-          up = (7.0 * (u(I-1,j,k) + u(I,j,k)) - (u(I-2,j,k) + u(I+1,j,k))) * C1_12
-          call UP3_reconstruction(u(I-2:I+1,j,k), up, um)
+          up = (7.0 * (u(I-1,j) + u(I,j)) - (u(I-2,j) + u(I+1,j))) * C1_12
+          call UP3_reconstruction(u(I-2:I+1,j), up, um)
         else
-          up = (u(I-1,j,k) + u(I,j,k))*0.5
+          up = (u(I-1,j) + u(I,j))*0.5
           if (up>0.) then
-            um = u(I-1,j,k)
+            um = u(I-1,j)
           elseif (up<0.) then
-            um = u(I,j,k)
+            um = u(I,j)
           else
             um = up
           endif
@@ -1354,14 +1350,14 @@ subroutine gradKE(u, v, h, KE, KEx, KEy, k, OBC, G, GV, US, CS)
         third_order_v = (G%mask2dCv(i,J-2) * G%mask2dCv(i,J-1)* &
                        G%mask2dCv(i,J) * G%mask2dCv(i,J+1))
         if (third_order_v ==1) then
-          vp = (7.0 * (v(i,J-1,k) + v(i,J,k)) - (v(i,J-2,k) + v(i,J+1,k))) * C1_12
-          call UP3_reconstruction(v(i,J-2:J+1,k), vp, vm)
+          vp = (7.0 * (v(i,J-1) + v(i,J)) - (v(i,J-2) + v(i,J+1))) * C1_12
+          call UP3_reconstruction(v(i,J-2:J+1), vp, vm)
         else
-          vp = (v(i,J-1,k) + v(i,J,k))*0.5
+          vp = (v(i,J-1) + v(i,J))*0.5
           if (vp>0.) then
-            vm = v(i,J-1,k)
+            vm = v(i,J-1)
           elseif (vp<0.) then
-            vm = v(i,J,k)
+            vm = v(i,J)
           else
             vm = vp
           endif
@@ -1374,28 +1370,14 @@ subroutine gradKE(u, v, h, KE, KEx, KEy, k, OBC, G, GV, US, CS)
 
   ! Term - d(KE)/dx.
   do j=js,je ; do I=Isq,Ieq
-    KEx(I,j) = (KE(i+1,j) - KE(i,j)) * G%IdxCu(I,j)
+    KEx(I,j) = (KE(i+1,j) - KE(i,j)) * G%IdxCu_OBCmask(I,j)
   enddo ; enddo
 
   ! Term - d(KE)/dy.
   do J=Jsq,Jeq ; do i=is,ie
-    KEy(i,J) = (KE(i,j+1) - KE(i,j)) * G%IdyCv(i,J)
+    KEy(i,J) = (KE(i,j+1) - KE(i,j)) * G%IdyCv_OBCmask(i,J)
   enddo ; enddo
 
-  if (associated(OBC)) then
-    do n=1,OBC%number_of_segments
-      if (OBC%segment(n)%is_N_or_S) then
-        do i=OBC%segment(n)%HI%isd,OBC%segment(n)%HI%ied
-          KEy(i,OBC%segment(n)%HI%JsdB) = 0.
-        enddo
-      elseif (OBC%segment(n)%is_E_or_W) then
-        do j=OBC%segment(n)%HI%jsd,OBC%segment(n)%HI%jed
-          KEx(OBC%segment(n)%HI%IsdB,j) = 0.
-        enddo
-      endif
-    enddo
-  endif
-
 end subroutine gradKE
 
 !> Reconstruct the scalar (e.g., pv, vorticity) onto point i-1/2 using a third-order upwind scheme
diff --git a/src/core/MOM_PressureForce_FV.F90 b/src/core/MOM_PressureForce_FV.F90
index b727c30595..b8cc03f405 100644
--- a/src/core/MOM_PressureForce_FV.F90
+++ b/src/core/MOM_PressureForce_FV.F90
@@ -22,7 +22,7 @@ module MOM_PressureForce_FV
 use MOM_density_integrals, only : int_spec_vol_dp_generic_plm
 use MOM_density_integrals, only : int_density_dz_generic_pcm, int_spec_vol_dp_generic_pcm
 use MOM_density_integrals, only : diagnose_mass_weight_Z, diagnose_mass_weight_p
-use MOM_ALE, only : TS_PLM_edge_values, TS_PPM_edge_values, ALE_CS
+use MOM_ALE, only : TS_PLM_edge_values, TS_PPM_edge_values, TS_PLM_WLS_edge_values, ALE_CS
 
 implicit none ; private
 
@@ -184,8 +184,7 @@ subroutine PressureForce_FV_nonBouss(h, tv, PFu, PFv, G, GV, US, CS, ALE_CSp, AD
     inty_dza    ! The change in inty_za through a layer [L2 T-2 ~> m2 s-2].
   real, dimension(SZI_(G),SZJ_(G)) :: &
     T_top, &    ! Temperature of top layer used with correction_intxpa [C ~> degC]
-    S_top, &    ! Salinity of top layer used with correction_intxpa [S ~> ppt]
-    SpV_top     ! Specific volume anomaly of top layer used with correction_intxpa [R-1 ~> m3 kg-1]
+    S_top       ! Salinity of top layer used with correction_intxpa [S ~> ppt]
   real, dimension(SZIB_(G),SZJ_(G)) :: &
     intx_za_cor ! Correction for curvature in intx_za [L2 T-2 ~> m2 s-2]
   real, dimension(SZI_(G),SZJB_(G)) :: &
@@ -197,8 +196,6 @@ subroutine PressureForce_FV_nonBouss(h, tv, PFu, PFv, G, GV, US, CS, ALE_CSp, AD
     T_int_W, T_int_E, & ! Temperatures on the reference interface to the east and west of a u-point [C ~> degC]
     S_int_W, S_int_E, & ! Salinities on the reference interface to the east and west of a u-point [S ~> ppt]
     p_int_W, p_int_E, & ! Pressures on the reference interface to the east and west of a u-point [R L2 T-2 ~> Pa]
-    SpV_x_W, SpV_x_E, & ! Specific volume anomalies on the reference interface to the east and west
-                        ! of a u-point [R-1 ~> m3 kg-1]
     intx_za_nonlin, &   ! Deviations in the previous version of intx_pa for the reference interface
                         ! from the value that would be obtained from assuming that pressure varies
                         ! linearly with depth along that interface [R L2 T-2 ~> Pa].
@@ -208,8 +205,6 @@ subroutine PressureForce_FV_nonBouss(h, tv, PFu, PFv, G, GV, US, CS, ALE_CSp, AD
     T_int_S, T_int_N, & ! Temperatures on the reference interface to the north and south of a v-point [C ~> degC]
     S_int_S, S_int_N, & ! Salinities on the reference interface to the north and south of a v-point [S ~> ppt]
     p_int_S, p_int_N, & ! Pressures on the reference interface to the north and south of a v-point [R L2 T-2 ~> Pa]
-    SpV_y_S, SpV_y_N, & ! Specific volume anomalies on the reference interface to the north and south
-                        ! of a v-point [R L2 T-2 ~> Pa]
     inty_za_nonlin, &   ! Deviations in the previous version of intx_pa for the reference interface
                         ! from the value that would be obtained from assuming that pressure varies
                         ! linearly with depth along that interface [L2 T-2 ~> m2 s-2].
@@ -353,6 +348,8 @@ subroutine PressureForce_FV_nonBouss(h, tv, PFu, PFv, G, GV, US, CS, ALE_CSp, AD
       call TS_PLM_edge_values(ALE_CSp, S_t, S_b, T_t, T_b, G, GV, tv, h, CS%boundary_extrap)
   elseif ( use_ALE .and. (CS%Recon_Scheme == 2) ) then
       call TS_PPM_edge_values(ALE_CSp, S_t, S_b, T_t, T_b, G, GV, tv, h, CS%boundary_extrap)
+  elseif ( use_ALE .and. (CS%Recon_Scheme == 3) ) then
+      call TS_PLM_WLS_edge_values(ALE_CSp, S_t, S_b, T_t, T_b, G, GV, tv, h)
   elseif (CS%reset_intxpa_integral) then
     do k=1,nz ; do j=Jsq,Jeq+1 ; do i=Isq,Ieq+1
       T_b(i,j,k) = tv%T(i,j,k) ; S_b(i,j,k) = tv%S(i,j,k)
@@ -365,7 +362,7 @@ subroutine PressureForce_FV_nonBouss(h, tv, PFu, PFv, G, GV, US, CS, ALE_CSp, AD
     ! subsequent calculation.
     if (use_EOS) then
       if ( use_ALE .and. CS%Recon_Scheme > 0 ) then
-        if ( CS%Recon_Scheme == 1 ) then
+        if ( CS%Recon_Scheme == 1 .or. CS%Recon_Scheme == 3 ) then
           call int_spec_vol_dp_generic_plm( T_t(:,:,k), T_b(:,:,k), S_t(:,:,k), S_b(:,:,k), &
                     p(:,:,K), p(:,:,K+1), alpha_ref, dp_neglect, p(:,:,nz+1), G%HI, &
                     tv%eqn_of_state, US, dza(:,:,k), intp_dza(:,:,k), intx_dza(:,:,k), inty_dza(:,:,k), &
@@ -436,8 +433,9 @@ subroutine PressureForce_FV_nonBouss(h, tv, PFu, PFv, G, GV, US, CS, ALE_CSp, AD
     else
       !$OMP parallel do default(shared)
       do j=Jsq,Jeq+1 ; do i=Isq,Ieq+1
-        SSH(i,j) = (za(i,j,1) - alpha_ref*p(i,j,1)) * I_gEarth - G%Z_ref &
-                  - max(-G%bathyT(i,j)-G%Z_ref, 0.0)
+        SSH(i,j) = (za(i,j,1) - alpha_ref*p(i,j,1)) * I_gEarth - G%Z_ref
+        ! Remove above sea level topography at floodable cells
+        SSH(i,j) = SSH(i,j) - max(-G%bathyT(i,j)-G%meanSL(i,j), 0.0)
       enddo ; enddo
       call calc_SAL(SSH, e_sal, G, CS%SAL_CSp, tmp_scale=US%Z_to_m)
     endif
@@ -1013,8 +1011,6 @@ subroutine PressureForce_FV_Bouss(h, tv, PFu, PFv, G, GV, US, CS, ALE_CSp, ADp,
     T_int_W, T_int_E, & ! Temperatures on the reference interface to the east and west of a u-point [C ~> degC]
     S_int_W, S_int_E, & ! Salinities on the reference interface to the east and west of a u-point [S ~> ppt]
     p_int_W, p_int_E, & ! Pressures on the reference interface to the east and west of a u-point [R L2 T-2 ~> Pa]
-    rho_x_W, rho_x_E, & ! Density anomalies on the reference interface to the east and west
-                        ! of a u-point [R ~> kg m-3]
     intx_pa_nonlin, &   ! Deviations in the previous version of intx_pa for the reference interface
                         ! from the value that would be obtained from assuming that pressure varies
                         ! linearly with depth along that interface [R L2 T-2 ~> Pa].
@@ -1024,8 +1020,6 @@ subroutine PressureForce_FV_Bouss(h, tv, PFu, PFv, G, GV, US, CS, ALE_CSp, ADp,
     T_int_S, T_int_N, & ! Temperatures on the reference interface to the north and south of a v-point [C ~> degC]
     S_int_S, S_int_N, & ! Salinities on the reference interface to the north and south of a v-point [S ~> ppt]
     p_int_S, p_int_N, & ! Pressures on the reference interface to the north and south of a v-point [R L2 T-2 ~> Pa]
-    rho_y_S, rho_y_N, & ! Density anomalies on the reference interface to the north and south
-                        ! of a v-point [R ~> kg m-3]
     inty_pa_nonlin, &   ! Deviations in the previous version of intx_pa for the reference interface
                         ! from the value that would be obtained from assuming that pressure varies
                         ! linearly with depth along that interface [R L2 T-2 ~> Pa].
@@ -1105,7 +1099,7 @@ subroutine PressureForce_FV_Bouss(h, tv, PFu, PFv, G, GV, US, CS, ALE_CSp, ADp,
   integer, dimension(2) :: EOSdom_u ! The i-computational domain for the equation of state at u-velocity points
   integer, dimension(2) :: EOSdom_v ! The i-computational domain for the equation of state at v-velocity points
   integer :: is, ie, js, je, Isq, Ieq, Jsq, Jeq, nz, nkmb
-  integer :: i, j, k, m, k2
+  integer :: i, j, k, m
 
   is = G%isc ; ie = G%iec ; js = G%jsc ; je = G%jec ; nz = GV%ke
   nkmb=GV%nk_rho_varies
@@ -1161,7 +1155,7 @@ subroutine PressureForce_FV_Bouss(h, tv, PFu, PFv, G, GV, US, CS, ALE_CSp, ADp,
     !$OMP parallel do default(shared)
     do j=Jsq,Jeq+1
       do i=Isq,Ieq+1
-        SSH(i,j) = min(-G%bathyT(i,j) - G%Z_ref, 0.0)
+        SSH(i,j) = min(-G%bathyT(i,j) - G%meanSL(i,j), 0.0)
       enddo
       do k=1,nz ; do i=Isq,Ieq+1
         SSH(i,j) = SSH(i,j) + h(i,j,k)*GV%H_to_Z
@@ -1240,6 +1234,8 @@ subroutine PressureForce_FV_Bouss(h, tv, PFu, PFv, G, GV, US, CS, ALE_CSp, ADp,
     call TS_PLM_edge_values(ALE_CSp, S_t, S_b, T_t, T_b, G, GV, tv, h, CS%boundary_extrap)
   elseif ( use_ALE .and. (CS%Recon_Scheme == 2) ) then
     call TS_PPM_edge_values(ALE_CSp, S_t, S_b, T_t, T_b, G, GV, tv, h, CS%boundary_extrap)
+  elseif ( use_ALE .and. (CS%Recon_Scheme == 3) ) then
+      call TS_PLM_WLS_edge_values(ALE_CSp, S_t, S_b, T_t, T_b, G, GV, tv, h)
   elseif (CS%reset_intxpa_integral) then
     do k=1,nz ; do j=Jsq,Jeq+1 ; do i=Isq,Ieq+1
       T_b(i,j,k) = tv%T(i,j,k) ; S_b(i,j,k) = tv%S(i,j,k)
@@ -1271,7 +1267,7 @@ subroutine PressureForce_FV_Bouss(h, tv, PFu, PFv, G, GV, US, CS, ALE_CSp, ADp,
     enddo ; enddo
   else
     do j=Jsq,Jeq+1 ; do i=Isq,Ieq+1
-      Z_0p(i,j) = G%Z_ref
+      Z_0p(i,j) = G%meanSL(i,j)
     enddo ; enddo
   endif
 
@@ -1285,7 +1281,7 @@ subroutine PressureForce_FV_Bouss(h, tv, PFu, PFv, G, GV, US, CS, ALE_CSp, ADp,
       ! is used, whereby densities within each layer are constant no matter
       ! where the layers are located.
       if ( use_ALE .and. CS%Recon_Scheme > 0 ) then
-        if ( CS%Recon_Scheme == 1 ) then
+        if ( CS%Recon_Scheme == 1 .or. CS%Recon_Scheme == 3 ) then
           call int_density_dz_generic_plm(k, tv, T_t, T_b, S_t, S_b, e, &
                     rho_ref, rho0_int_density, GV%g_Earth, dz_neglect, G%bathyT, &
                     G%HI, GV, tv%eqn_of_state, US, CS%use_stanley_pgf, dpa(:,:,k), intz_dpa(:,:,k), &
@@ -1355,7 +1351,9 @@ subroutine PressureForce_FV_Bouss(h, tv, PFu, PFv, G, GV, US, CS, ALE_CSp, ADp,
     else
       !$OMP parallel do default(shared)
       do j=Jsq,Jeq+1 ; do i=Isq,Ieq+1
-        SSH(i,j) = e(i,j,1) - max(-G%bathyT(i,j) - G%Z_ref, 0.0) ! Remove topography above sea level
+        SSH(i,j) = e(i,j,1) - G%Z_ref
+        ! Remove above sea level topography at floodable cells
+        SSH(i,j) = SSH(i,j) - max(-G%bathyT(i,j)-G%meanSL(i,j), 0.0)
       enddo ; enddo
       call calc_SAL(SSH, e_sal, G, CS%SAL_CSp, tmp_scale=US%Z_to_m)
     endif
@@ -2038,7 +2036,6 @@ subroutine PressureForce_FV_init(Time, G, GV, US, param_file, diag, CS, ADp, SAL
   logical :: useMassWghtInterp ! If true, use near-bottom mass weighting for T and S
   logical :: MassWghtInterpTop ! If true, use near-surface mass weighting for T and S under ice shelves
   logical :: MassWghtInterp_NonBous_bug ! If true, use a buggy mass weighting when non-Boussinesq
-  logical :: MassWghtInterpVanOnly ! If true, turn of mass weighting unless one side is vanished
   logical :: enable_bugs  ! If true, the defaults for recently added bug-fix flags are set to
                           ! recreate the bugs, or if false bugs are only used if actively selected.
   ! This include declares and sets the variable "version".
@@ -2078,16 +2075,16 @@ subroutine PressureForce_FV_init(Time, G, GV, US, param_file, diag, CS, ADp, SAL
                  "If true, apply tidal momentum forcing.", default=.false.)
   if (CS%tides) then
     call get_param(param_file, mdl, "DEFAULT_ANSWER_DATE", default_answer_date, &
-                 "This sets the default value for the various _ANSWER_DATE parameters.", &
-                 default=99991231)
+                   "This sets the default value for the various _ANSWER_DATE parameters.", &
+                   default=99991231)
     call get_param(param_file, mdl, "TIDES_ANSWER_DATE", CS%tides_answer_date, "The vintage of "//&
-                  "self-attraction and loading (SAL) and tidal forcing calculations.  Setting "//&
-                  "dates before 20230701 recovers old answers (Boussinesq and non-Boussinesq "//&
-                  "modes) when SAL is part of the tidal forcing calculation.  The answer "//&
-                  "difference is only at bit level and due to a reordered summation.  Setting "//&
-                  "dates before 20250201 recovers answers (Boussinesq mode) that interface "//&
-                  "heights are modified before pressure force integrals are calculated.", &
-                  default=default_answer_date, do_not_log=(.not.CS%tides))
+                   "self-attraction and loading (SAL) and tidal forcing calculations.  Setting "//&
+                   "dates before 20230701 recovers old answers (Boussinesq and non-Boussinesq "//&
+                   "modes) when SAL is part of the tidal forcing calculation.  The answer "//&
+                   "difference is only at bit level and due to a reordered summation.  Setting "//&
+                   "dates before 20250201 recovers answers (Boussinesq mode) that interface "//&
+                   "heights are modified before pressure force integrals are calculated.", &
+                   default=default_answer_date, do_not_log=(.not.CS%tides))
   endif
   call get_param(param_file, mdl, "CALCULATE_SAL", CS%calculate_SAL, &
                  "If true, calculate self-attraction and loading.", default=CS%tides)
@@ -2183,7 +2180,8 @@ subroutine PressureForce_FV_init(Time, G, GV, US, param_file, diag, CS, ADp, SAL
                  "integrals within the FV pressure gradient calculation.\n"//&
                  " 0: PCM or no reconstruction.\n"//&
                  " 1: PLM reconstruction.\n"//&
-                 " 2: PPM reconstruction.", default=1)
+                 " 2: PPM reconstruction.\n"//&
+                 " 3: PLM with least squares slope.", default=1)
   call get_param(param_file, mdl, "BOUNDARY_EXTRAPOLATION_PRESSURE", CS%boundary_extrap, &
                  "If true, the reconstruction of T & S for pressure in "//&
                  "boundary cells is extrapolated, rather than using PCM "//&
diff --git a/src/core/MOM_PressureForce_Montgomery.F90 b/src/core/MOM_PressureForce_Montgomery.F90
index 1529af9d83..0098470502 100644
--- a/src/core/MOM_PressureForce_Montgomery.F90
+++ b/src/core/MOM_PressureForce_Montgomery.F90
@@ -197,7 +197,7 @@ subroutine PressureForce_Mont_nonBouss(h, tv, PFu, PFv, G, GV, US, CS, p_atm, pb
     ! of self-attraction and loading.
     !$OMP parallel do default(shared)
     do j=Jsq,Jeq+1 ; do i=Isq,Ieq+1
-      SSH(i,j) = min(-G%bathyT(i,j) - G%Z_ref, 0.0)
+      SSH(i,j) = min(-G%bathyT(i,j) - G%meanSL(i,j), 0.0)
     enddo ; enddo
     if (use_EOS) then
       !$OMP parallel do default(shared)
@@ -476,7 +476,7 @@ subroutine PressureForce_Mont_Bouss(h, tv, PFu, PFv, G, GV, US, CS, p_atm, pbce,
     ! barotropic tides.
     !$OMP parallel do default(shared)
     do j=Jsq,Jeq+1
-      do i=Isq,Ieq+1 ; SSH(i,j) = min(-G%bathyT(i,j) - G%Z_ref, 0.0) ; enddo
+      do i=Isq,Ieq+1 ; SSH(i,j) = min(-G%bathyT(i,j) - G%meanSL(i,j), 0.0) ; enddo
       do k=1,nz ; do i=Isq,Ieq+1
         SSH(i,j) = SSH(i,j) + h(i,j,k)*GV%H_to_Z
       enddo ; enddo
@@ -707,7 +707,7 @@ subroutine Set_pbce_Bouss(e, tv, G, GV, US, Rho0, GFS_scale, pbce, rho_star)
       do j=Jsq,Jeq+1
         do i=Isq,Ieq+1
           Ihtot(i) = GV%H_to_Z / ((e(i,j,1)-e(i,j,nz+1)) + dz_neglect)
-          press(i) = -Rho0xG*(e(i,j,1) - G%Z_ref)
+          press(i) = -Rho0xG*(e(i,j,1) - G%meanSL(i,j))
         enddo
         call calculate_density(tv%T(:,j,1), tv%S(:,j,1), press, rho_in_situ, &
                                tv%eqn_of_state, EOSdom)
@@ -716,7 +716,7 @@ subroutine Set_pbce_Bouss(e, tv, G, GV, US, Rho0, GFS_scale, pbce, rho_star)
         enddo
         do k=2,nz
           do i=Isq,Ieq+1
-            press(i) = -Rho0xG*(e(i,j,K) - G%Z_ref)
+            press(i) = -Rho0xG*(e(i,j,K) - G%meanSL(i,j))
             T_int(i) = 0.5*(tv%T(i,j,k-1)+tv%T(i,j,k))
             S_int(i) = 0.5*(tv%S(i,j,k-1)+tv%S(i,j,k))
           enddo
diff --git a/src/core/MOM_barotropic.F90 b/src/core/MOM_barotropic.F90
index ac2e668f8e..4dbac78c98 100644
--- a/src/core/MOM_barotropic.F90
+++ b/src/core/MOM_barotropic.F90
@@ -600,13 +600,8 @@ subroutine btstep(U_in, V_in, eta_in, dt, bc_accel_u, bc_accel_v, forces, pbce,
     uhbt0, &      ! The difference between the sum of the layer zonal thickness
                   ! fluxes and the barotropic thickness flux using the same
                   ! velocity [H L2 T-1 ~> m3 s-1 or kg s-1].
-    ubt_prev, &   ! The starting value of ubt in a barotropic step [L T-1 ~> m s-1].
-    ubt_first, &  ! The starting value of ubt in a series of barotropic steps [L T-1 ~> m s-1].
-    ubt_trans, &  ! The latest value of ubt used for a transport [L T-1 ~> m s-1].
-    Cor_u, &      ! The zonal Coriolis acceleration [L T-2 ~> m s-2].
     Cor_ref_u, &  ! The zonal barotropic Coriolis acceleration due
                   ! to the reference velocities [L T-2 ~> m s-2].
-    PFu, &        ! The zonal pressure force acceleration [L T-2 ~> m s-2].
     Rayleigh_u, & ! A Rayleigh drag timescale operating at u-points for drag parameterizations
                   ! that introduced directly into the barotropic solver rather than coming in via
                   ! the visc_rem_u arrays from the layered equations [T-1 ~> s-1].
@@ -627,13 +622,8 @@ subroutine btstep(U_in, V_in, eta_in, dt, bc_accel_u, bc_accel_v, forces, pbce,
     vhbt0, &      ! The difference between the sum of the layer meridional
                   ! thickness fluxes and the barotropic thickness flux using
                   ! the same velocities [H L2 T-1 ~> m3 s-1 or kg s-1].
-    vbt_prev, &   ! The starting value of vbt in a barotropic step [L T-1 ~> m s-1].
-    vbt_first, &  ! The starting value of vbt in a series of barotropic steps [L T-1 ~> m s-1].
-    vbt_trans, &  ! The latest value of vbt used for a transport [L T-1 ~> m s-1].
-    Cor_v, &      ! The meridional Coriolis acceleration [L T-2 ~> m s-2].
     Cor_ref_v, &  ! The meridional barotropic Coriolis acceleration due
                   ! to the reference velocities [L T-2 ~> m s-2].
-    PFv, &        ! The meridional pressure force acceleration [L T-2 ~> m s-2].
     Rayleigh_v, & ! A Rayleigh drag timescale operating at v-points for drag parameterizations
                   ! that introduced directly into the barotropic solver rather than coming
                   ! in via the visc_rem_v arrays from the layered equations [T-1 ~> s-1].
@@ -662,9 +652,8 @@ subroutine btstep(U_in, V_in, eta_in, dt, bc_accel_u, bc_accel_v, forces, pbce,
   real, dimension(SZI_(G),SZJB_(G)) :: Drag_v
                   ! The meridional acceleration due to frequency-dependent drag [L T-2 ~> m s-2]
   real, target, dimension(SZIW_(CS),SZJW_(CS)) :: &
-    eta, &        ! The barotropic free surface height anomaly or column mass
+    eta           ! The barotropic free surface height anomaly or column mass
                   ! anomaly [H ~> m or kg m-2]
-    eta_pred      ! A predictor value of eta [H ~> m or kg m-2] like eta.
   real, dimension(SZIW_(CS),SZJW_(CS)) :: &
     eta_sum, &    ! eta summed across the timesteps [H ~> m or kg m-2].
     eta_wtd, &    ! A weighted estimate used to calculate eta_out [H ~> m or kg m-2].
@@ -694,7 +683,6 @@ subroutine btstep(U_in, V_in, eta_in, dt, bc_accel_u, bc_accel_v, forces, pbce,
   ! End of wide-sized variables.
 
   real :: visc_rem    ! A work variable that may equal visc_rem_[uv] [nondim]
-  real :: vel_prev    ! The previous velocity [L T-1 ~> m s-1].
   real :: dtbt        ! The barotropic time step [T ~> s].
   real :: Idt         ! The inverse of dt [T-1 ~> s-1].
   real :: det_de      ! The partial derivative due to self-attraction and loading
@@ -755,13 +743,11 @@ subroutine btstep(U_in, V_in, eta_in, dt, bc_accel_u, bc_accel_v, forces, pbce,
   logical :: apply_OBCs, apply_OBC_flather
   type(memory_size_type) :: MS
   character(len=200) :: mesg
-  integer :: isv, iev, jsv, jev ! The valid array size at the end of a step.
   integer :: stencil  ! The stencil size of the algorithm, often 1 or 2.
   integer :: isvf, ievf, jsvf, jevf, num_cycles
   integer :: i, j, k, n
   integer :: is, ie, js, je, nz, Isq, Ieq, Jsq, Jeq
   integer :: isd, ied, jsd, jed, IsdB, IedB, JsdB, JedB
-  integer :: l_seg
 
   if (.not.CS%module_is_initialized) call MOM_error(FATAL, &
       "btstep: Module MOM_barotropic must be initialized before it is used.")
@@ -1328,8 +1314,11 @@ subroutine btstep(U_in, V_in, eta_in, dt, bc_accel_u, bc_accel_v, forces, pbce,
   uhbt(:,:) = 0.0 ; vhbt(:,:) = 0.0
   u_accel_bt(:,:) = 0.0 ; v_accel_bt(:,:) = 0.0
 
-  if (apply_OBCs) then
-    ubt_first(:,:) = ubt(:,:) ; vbt_first(:,:) = vbt(:,:)
+  if (apply_OBCs .or. (CS%id_ubtdt > 0)) then
+    do j=js,je ; do I=is-1,ie ; ubt_st(I,j) = ubt(I,j) ; enddo ; enddo
+  endif
+  if (apply_OBCs .or. (CS%id_vbtdt > 0)) then
+    do J=js-1,je ; do i=is,ie ; vbt_st(i,J) = vbt(i,J) ; enddo ; enddo
   endif
 
 !   Here the vertical average accelerations due to the Coriolis, advective,
@@ -1800,17 +1789,6 @@ subroutine btstep(U_in, V_in, eta_in, dt, bc_accel_u, bc_accel_v, forces, pbce,
     endif
   endif
 
-  if (CS%id_ubtdt > 0) then
-    do j=js-1,je+1 ; do I=is-1,ie
-      ubt_st(I,j) = ubt(I,j)
-    enddo ; enddo
-  endif
-  if (CS%id_vbtdt > 0) then
-    do J=js-1,je ; do i=is-1,ie+1
-      vbt_st(i,J) = vbt(i,J)
-    enddo ; enddo
-  endif
-
   if (query_averaging_enabled(CS%diag)) then
     if (CS%id_eta_st > 0) call post_data(CS%id_eta_st, eta(isd:ied,jsd:jed), CS%diag)
     if (CS%id_ubt_st > 0) call post_data(CS%id_ubt_st, ubt(IsdB:IedB,jsd:jed), CS%diag)
@@ -2026,13 +2004,13 @@ subroutine btstep(U_in, V_in, eta_in, dt, bc_accel_u, bc_accel_v, forces, pbce,
     ! symmetric-memory computational domain, not in the wide halo regions.
     if (CS%BT_OBC%u_OBCs_on_PE) then ; do j=js,je ; do I=is-1,ie
       if (CS%BT_OBC%u_OBC_type(I,j) /= 0) then
-        u_accel_bt(I,j) = (ubt_wtd(I,j) - ubt_first(I,j)) / dt
+        u_accel_bt(I,j) = (ubt_wtd(I,j) - ubt_st(I,j)) / dt
         do k=1,nz ; accel_layer_u(I,j,k) = u_accel_bt(I,j) ; enddo
       endif
     enddo ; enddo ; endif
     if (CS%BT_OBC%v_OBCs_on_PE) then ; do J=js-1,je ; do i=is,ie
       if (CS%BT_OBC%v_OBC_type(i,J) /= 0) then
-        v_accel_bt(i,J) = (vbt_wtd(i,J) - vbt_first(i,J)) / dt
+        v_accel_bt(i,J) = (vbt_wtd(i,J) - vbt_st(i,J)) / dt
         do k=1,nz ; accel_layer_v(i,J,k) = v_accel_bt(i,J) ; enddo
       endif
     enddo ; enddo ; endif
@@ -2470,9 +2448,9 @@ subroutine btstep_timeloop(eta, ubt, vbt, uhbt0, Datu, BTCL_u, vhbt0, Datv, BTCL
     PFu, &        ! The zonal pressure force acceleration [L T-2 ~> m s-2]
     Cor_u, &      ! The zonal Coriolis acceleration [L T-2 ~> m s-2]
     ubt_int, &    ! The running time integral of ubt over the time steps [L ~> m]
-    uhbt_int, &   ! The running time integral of uhbt over the time steps [H L2  ~> m3]
+    uhbt_int, &   ! The running time integral of uhbt over the time steps [H L2 ~> m3 or kg]
     ubt_int_prev, & ! Previous value of time-integrated velocity stored for OBCs [L ~> m]
-    uhbt_int_prev   ! Previous value of time-integrated transport stored for integral_BT_cont [L2 H ~> m3]
+    uhbt_int_prev   ! Previous value of time-integrated transport stored for integral_BT_cont [H L2 ~> m3 or kg]
   real, dimension(SZIW_(CS),SZJBW_(CS)) :: &
     vhbt, &       ! The meridional barotropic thickness fluxes [H L2 T-1 ~> m3 s-1 or kg s-1]
     vbt_prev, &   ! The starting value of vbt in a barotropic step [L T-1 ~> m s-1]
@@ -2480,14 +2458,14 @@ subroutine btstep_timeloop(eta, ubt, vbt, uhbt0, Datu, BTCL_u, vhbt0, Datv, BTCL
     PFv, &        ! The meridional pressure force acceleration [L T-2 ~> m s-2]
     Cor_v, &      ! The meridional Coriolis acceleration [L T-2 ~> m s-2]
     vbt_int, &    ! The running time integral of vbt over the time steps [L ~> m]
-    vhbt_int, &   ! The running time integral of vhbt over the time steps [H L2  ~> m3]
+    vhbt_int, &   ! The running time integral of vhbt over the time steps [H L2 ~> m3 or kg]
     vbt_int_prev, & ! Previous value of time-integrated velocity stored for OBCs [L ~> m]
-    vhbt_int_prev   ! Previous value of time-integrated transport stored for integral_BT_cont [L2 H ~> m3]
+    vhbt_int_prev   ! Previous value of time-integrated transport stored for integral_BT_cont [H L2 ~> m3 or kg]
   real, target, dimension(SZIW_(CS),SZJW_(CS)) :: &
     eta_pred      ! A predictor value of eta [H ~> m or kg m-2] like eta
   real, dimension(SZIW_(CS),SZJW_(CS)) :: &
     p_surf_dyn, & !< A dynamic surface pressure under rigid ice [L2 T-2 ~> m2 s-2]
-    cfl_ltd_vol   !< The volume available after removing sinks used to limit uhbt_int and vhbt_int [H L2 ~> m3]
+    cfl_ltd_vol   !< The volume available after removing sinks used to limit uhbt_int and vhbt_int [H L2 ~> m3 or kg]
   real, dimension(SZI_(G),SZJ_(G)) :: &
     eta_anom_PF   ! The eta anomalies used to find the pressure force anomalies [H ~> m or kg m-2]
   real :: wt_end      ! The weighting of the final value of eta_PF [nondim]
@@ -2506,6 +2484,7 @@ subroutine btstep_timeloop(eta, ubt, vbt, uhbt0, Datu, BTCL_u, vhbt0, Datv, BTCL
                       ! to equal bebt, as they have similar roles and meanings.
   real :: eta_cor_multiplier ! Increases the rate of applying CS%eta_cor so that the mass
                       ! source is all used up by the beginning of the filtering [nondim]
+  real :: eta_acc     ! Change due to divergence of mass transport [H ~> m or kg m-2]
   logical :: do_hifreq_output  ! If true, output occurs every barotropic step.
   logical :: do_ave   ! If true, diagnostics are enabled on this step.
   logical :: evolving_face_areas
@@ -2882,7 +2861,21 @@ subroutine btstep_timeloop(eta, ubt, vbt, uhbt0, Datu, BTCL_u, vhbt0, Datv, BTCL
       do j=jsv,jev ; do i=isv,iev
         eta(i,j) = (eta_IC(i,j) + eta_cor_multiplier*eta_src(i,j)) + CS%IareaT_OBCmask(i,j) * &
                    ((uhbt_int(I-1,j) - uhbt_int(I,j)) + (vhbt_int(i,J-1) - vhbt_int(i,J)))
+        ! eta_acc contains the magnitude of the largest term in the above expression which
+        ! will be used to estimate a bound for round off when comparing to the bottom depth
+        eta_acc = abs( CS%IareaT_OBCmask(i,j) * &
+                   ((uhbt_int(I-1,j) - uhbt_int(I,j)) + (vhbt_int(i,J-1) - vhbt_int(i,J))) )
+        eta_acc = max( eta_acc, abs( eta_cor_multiplier*eta_src(i,j) ), abs( eta_IC(i,j) ) )
+        if ( G%mask2dT(i,j) * ( eta(i,j) + GV%Z_to_H*G%bathyT(i,j) ) > &
+             -G%mask2dT(i,j) * eta_acc * epsilon(eta_acc) * 2. ) &
+          eta(i,j) = max( eta(i,j), -GV%Z_to_H*G%bathyT(i,j) )
         eta_wtd(i,j) = eta_wtd(i,j) + eta(i,j) * wt_eta(n)
+        if ((eta(i,j) < -GV%Z_to_H*G%bathyT(i,j)) .and. (G%mask2dT(i,j) > 0.0)) then
+          write(mesg,'(ES24.16," vs. ",ES24.16, " at ", ES12.4, ES12.4, i7, i7)') GV%H_to_m*eta(i,j), &
+               -US%Z_to_m*G%bathyT(i,j), G%geoLonT(i,j), G%geoLatT(i,j), i + G%HI%idg_offset, j + G%HI%jdg_offset
+          if (CS%bt_limit_integral_transport) &
+            call MOM_error(FATAL, "btstep: eta has dropped below bathyT: "//trim(mesg))
+        endif
       enddo ; enddo
     else
       !$OMP do
@@ -3042,7 +3035,7 @@ subroutine btstep_find_Cor(q, DCor_u, DCor_v, f_4_u, f_4_v, isvf, ievf, jsvf, je
   integer, intent(in) :: jsvf  !< The starting j-index of the largest valid range for tracer points
   integer, intent(in) :: jevf  !< The ending j-index of the largest valid range for tracer points
 
-  real :: C1_3 ! One third [nondim]
+  ! real :: C1_3 ! One third [nondim]
   integer :: i, j
 
   if (CS%Sadourny) then
@@ -3181,9 +3174,9 @@ subroutine btloop_eta_predictor(n, dtbt, ubt, vbt, eta, ubt_int, vbt_int, uhbt,
   real, dimension(SZIW_(CS),SZJBW_(CS)), intent(inout) :: &
     vhbt          !< The meridional barotropic thickness fluxes [H L2 T-1 ~> m3 s-1 or kg s-1].
   real, dimension(SZIBW_(CS),SZJW_(CS)), intent(inout) :: &
-    uhbt_int      !< The running time integral of uhbt over the time steps [H L2  ~> m3].
+    uhbt_int      !< The running time integral of uhbt over the time steps [H L2 ~> m3 or kg].
   real, dimension(SZIW_(CS),SZJBW_(CS)), intent(inout) :: &
-    vhbt_int      !< The running time integral of vhbt over the time steps [H L2  ~> m3].
+    vhbt_int      !< The running time integral of vhbt over the time steps [H L2 ~> m3 or kg].
   real, target, dimension(SZIW_(CS),SZJW_(CS)), intent(inout) :: &
     eta_pred      !< A predictor value of eta [H ~> m or kg m-2] like eta.
   integer, intent(in)  :: isv         !< The starting i-index of eta_pred to calculate
@@ -3533,7 +3526,6 @@ subroutine btloop_update_u(dtbt, ubt, vbt, u_accel_bt, &
   type(unit_scale_type),   intent(in)  :: US      !< A dimensional unit scaling type
 
   ! Local variables
-  real :: vel_prev    ! The previous velocity [L T-1 ~> m s-1].
   integer :: i, j
 
   !$OMP do schedule(static)
@@ -4590,7 +4582,6 @@ subroutine btcalc(h, G, GV, CS, h_u, h_v, may_use_default, OBC)
 
   logical :: use_default, test_dflt
   integer :: is, ie, js, je, Isq, Ieq, Jsq, Jeq, nz, i, j, k
-  integer :: is_v, ie_v, Js_v, Je_v
 
   if (.not.CS%module_is_initialized) call MOM_error(FATAL, &
       "btcalc: Module MOM_barotropic must be initialized before it is used.")
@@ -5358,14 +5349,14 @@ subroutine find_face_areas(Datu, Datv, G, GV, US, CS, MS, halo, eta, add_max)
         H1 = CS%bathyT(i,j)*GV%Z_to_H + eta(i,j) ; H2 = CS%bathyT(i+1,j)*GV%Z_to_H + eta(i+1,j)
         Datu(I,j) = 0.0 ; if ((H1 > 0.0) .and. (H2 > 0.0)) &
         Datu(I,j) = CS%dy_Cu(I,j) * (2.0 * H1 * H2) / (H1 + H2)
-!       Datu(I,j) = CS%dy_Cu(I,j) * 0.5 * (H1 + H2)
+        ! Datu(I,j) = CS%dy_Cu(I,j) * 0.5 * (H1 + H2)
       enddo ; enddo
       !$OMP do
       do J=js-1-hs,je+hs ; do i=is-hs,ie+hs
         H1 = CS%bathyT(i,j)*GV%Z_to_H + eta(i,j) ; H2 = CS%bathyT(i,j+1)*GV%Z_to_H + eta(i,j+1)
         Datv(i,J) = 0.0 ; if ((H1 > 0.0) .and. (H2 > 0.0)) &
         Datv(i,J) = CS%dx_Cv(i,J) * (2.0 * H1 * H2) / (H1 + H2)
-!       Datv(i,J) = CS%dy_v(i,J) * 0.5 * (H1 + H2)
+        ! Datv(i,J) = CS%dy_v(i,J) * 0.5 * (H1 + H2)
       enddo ; enddo
     else
       !$OMP do
@@ -5388,27 +5379,31 @@ subroutine find_face_areas(Datu, Datv, G, GV, US, CS, MS, halo, eta, add_max)
 
     !$OMP do
     do j=js-hs,je+hs ; do I=is-1-hs,ie+hs
-      Datu(I,j) = CS%dy_Cu(I,j) * Z_to_H * &
-                 max(max(CS%bathyT(i+1,j), CS%bathyT(i,j)) + (G%Z_ref + add_max), 0.0)
+      H1 = max((G%meanSL(i+1,j) + add_max) + G%bathyT(i+1,j), 0.0)
+      H2 = max((G%meanSL(i,j) + add_max) + G%bathyT(i,j), 0.0)
+      Datu(I,j) = CS%dy_Cu(I,j) * Z_to_H * max(H1, H2)
     enddo ; enddo
     !$OMP do
     do J=js-1-hs,je+hs ; do i=is-hs,ie+hs
-      Datv(i,J) = CS%dx_Cv(i,J) * Z_to_H * &
-                 max(max(CS%bathyT(i,j+1), CS%bathyT(i,j)) + (G%Z_ref + add_max), 0.0)
+      H1 = max((G%meanSL(i,j+1) + add_max) + G%bathyT(i,j+1), 0.0)
+      H2 = max((G%meanSL(i,j) + add_max) + G%bathyT(i,j), 0.0)
+      Datv(i,J) = CS%dx_Cv(i,J) * Z_to_H * max(H1, H2)
     enddo ; enddo
   else
     Z_to_H = GV%Z_to_H ; if (.not.GV%Boussinesq) Z_to_H = GV%RZ_to_H * CS%Rho_BT_lin
 
     !$OMP do
     do j=js-hs,je+hs ; do I=is-1-hs,ie+hs
-      H1 = (CS%bathyT(i,j) + G%Z_ref) * Z_to_H ; H2 = (CS%bathyT(i+1,j) + G%Z_ref) * Z_to_H
+      H1 = max(G%meanSL(i,j) + G%bathyT(i,j), 0.0) * Z_to_H
+      H2 = max(G%meanSL(i+1,j) + G%bathyT(i+1,j), 0.0) * Z_to_H
       Datu(I,j) = 0.0
       if ((H1 > 0.0) .and. (H2 > 0.0)) &
         Datu(I,j) = CS%dy_Cu(I,j) * (2.0 * H1 * H2) / (H1 + H2)
     enddo ; enddo
     !$OMP do
     do J=js-1-hs,je+hs ; do i=is-hs,ie+hs
-      H1 = (CS%bathyT(i,j) + G%Z_ref) * Z_to_H ; H2 = (CS%bathyT(i,j+1) + G%Z_ref) * Z_to_H
+      H1 = max(G%meanSL(i,j) + G%bathyT(i,j), 0.0) * Z_to_H
+      H2 = max(G%meanSL(i,j+1) + G%bathyT(i,j+1), 0.0) * Z_to_H
       Datv(i,J) = 0.0
       if ((H1 > 0.0) .and. (H2 > 0.0)) &
         Datv(i,J) = CS%dx_Cv(i,J) * (2.0 * H1 * H2) / (H1 + H2)
@@ -5531,8 +5526,7 @@ subroutine barotropic_init(u, v, h, Time, G, GV, US, param_file, diag, CS, &
                                        ! name in wave_drag_file.
   character(len=80)  :: wave_drag_v    ! The wave drag piston velocity variable
                                        ! name in wave_drag_file.
-  real :: mean_SL     ! The mean sea level that is used along with the bathymetry to estimate the
-                      ! geometry when LINEARIZED_BT_CORIOLIS is true or BT_NONLIN_STRESS is false [Z ~> m].
+  real :: htot        ! Total column thickness used when BT_NONLIN_STRESS is false [Z ~> m].
   real :: Z_to_H      ! A local unit conversion factor [H Z-1 ~> nondim or kg m-3]
   real :: H_to_Z      ! A local unit conversion factor [Z H-1 ~> nondim or m3 kg-1]
   real :: det_de      ! The partial derivative due to self-attraction and loading of the reference
@@ -6021,10 +6015,10 @@ subroutine barotropic_init(u, v, h, Time, G, GV, US, param_file, diag, CS, &
   ! This sets pressure force diagnostics on land, at coastlines and at OBC points to zero.
   if (mask_coastal_pressure_force) then
     do j=G%jsd,G%jed ; do I=G%IsdB,G%IedB
-      CS%IdxCu(I,j) = G%OBCmaskCu(I,j) * G%IdxCu(I,j)
+      CS%IdxCu(I,j) = G%IdxCu_OBCmask(I,j)
     enddo ; enddo
     do J=G%JsdB,G%JedB ; do i=G%isd,G%ied
-      CS%IdyCv(i,J) = G%OBCmaskCv(i,J) * G%IdyCv(i,J)
+      CS%IdyCv(i,J) = G%IdyCv_OBCmask(i,J)
     enddo ; enddo
   endif
 
@@ -6134,25 +6128,26 @@ subroutine barotropic_init(u, v, h, Time, G, GV, US, param_file, diag, CS, &
 
     Z_to_H = GV%Z_to_H ; if (.not.GV%Boussinesq) Z_to_H = GV%RZ_to_H * CS%Rho_BT_lin
 
-    Mean_SL = G%Z_ref
     do j=js,je ; do I=is-1,ie
-      CS%D_u_Cor(I,j) = 0.5 * (max(Mean_SL+G%bathyT(i+1,j),0.0) + max(Mean_SL+G%bathyT(i,j),0.0)) * Z_to_H
+      CS%D_u_Cor(I,j) = 0.5 * ( max(G%meanSL(i+1,j) + G%bathyT(i+1,j), 0.0) &
+                              + max(G%meanSL(i,j) + G%bathyT(i,j), 0.0) ) * Z_to_H
     enddo ; enddo
     if (CS%interior_OBC_PV .and. CS%BT_OBC%u_OBCs_on_PE) then ; do j=js,je ; do I=is-1,ie
       if (CS%BT_OBC%u_OBC_type(I,j) < 0) & ! Western boundary condition
-        CS%D_u_Cor(I,j) = max(Mean_SL+G%bathyT(i+1,j),0.0) * Z_to_H
+        CS%D_u_Cor(I,j) = max(G%meanSL(i+1,j) + G%bathyT(i+1,j), 0.0) * Z_to_H
       if (CS%BT_OBC%u_OBC_type(I,j) > 0) & ! Eastern boundary condition
-        CS%D_u_Cor(I,j) = max(Mean_SL+G%bathyT(i,j),0.0) * Z_to_H
+        CS%D_u_Cor(I,j) = max(G%meanSL(i,j) + G%bathyT(i,j), 0.0) * Z_to_H
     enddo ; enddo ; endif
 
     do J=js-1,je ; do i=is,ie
-      CS%D_v_Cor(i,J) = 0.5 * (max(Mean_SL+G%bathyT(i,j+1),0.0) + max(Mean_SL+G%bathyT(i,j),0.0)) * Z_to_H
+      CS%D_v_Cor(i,J) = 0.5 * ( max(G%meanSL(i,j+1) + G%bathyT(i,j+1), 0.0) &
+                              + max(G%meanSL(i,j) + G%bathyT(i,j), 0.0) )  * Z_to_H
     enddo ; enddo
     if (CS%interior_OBC_PV .and. CS%BT_OBC%v_OBCs_on_PE) then ; do J=js-1,je ; do i=is,ie
       if (CS%BT_OBC%v_OBC_type(i,J) < 0) & ! Southern boundary condition
-        CS%D_v_Cor(i,J) = max(Mean_SL+G%bathyT(i,j+1),0.0) * Z_to_H
+        CS%D_v_Cor(i,J) = max(G%meanSL(i,j+1) + G%bathyT(i,j+1), 0.0) * Z_to_H
       if (CS%BT_OBC%v_OBC_type(i,J) > 0) & ! Northern boundary condition
-        CS%D_v_Cor(i,J) = max(Mean_SL+G%bathyT(i,j),0.0) * Z_to_H
+        CS%D_v_Cor(i,J) = max(G%meanSL(i,j) + G%bathyT(i,j), 0.0) * Z_to_H
     enddo ; enddo ; endif
 
     h_a_neglect = GV%H_subroundoff * 1.0 * US%m_to_L**2
@@ -6160,10 +6155,11 @@ subroutine barotropic_init(u, v, h, Time, G, GV, US, param_file, diag, CS, &
       if ((CS%q_wt(1,I,J) + CS%q_wt(4,I,J)) + (CS%q_wt(2,I,J) + CS%q_wt(3,I,J)) > 0.) then
         CS%q_D(I,J) = 0.25 * (CS%BT_Coriolis_scale * G%CoriolisBu(I,J)) * &
            ((CS%q_wt(1,I,J) + CS%q_wt(4,I,J)) + (CS%q_wt(2,I,J) + CS%q_wt(3,I,J))) / &
-           max(Z_to_H * (((CS%q_wt(1,I,J) * max(Mean_SL+G%bathyT(i,j),0.0)) + &
-                          (CS%q_wt(4,I,J) * max(Mean_SL+G%bathyT(i+1,j+1),0.0))) + &
-                         ((CS%q_wt(2,I,J) * max(Mean_SL+G%bathyT(i+1,j),0.0)) + &
-                          (CS%q_wt(3,I,J) * max(Mean_SL+G%bathyT(i,j+1),0.0)))), h_a_neglect)
+           max(Z_to_H * (((CS%q_wt(1,I,J) * max(G%meanSL(i,j) + G%bathyT(i,j), 0.0)) + &
+                          (CS%q_wt(4,I,J) * max(G%meanSL(i+1,j+1) + G%bathyT(i+1,j+1), 0.0))) + &
+                         ((CS%q_wt(2,I,J) * max(G%meanSL(i+1,j) + G%bathyT(i+1,j), 0.0)) + &
+                          (CS%q_wt(3,I,J) * max(G%meanSL(i,j+1) + G%bathyT(i,j+1), 0.0)))), &
+               h_a_neglect)
       else ! All four h points are masked out so q_D(I,J) is meaningless
         CS%q_D(I,J) = 0.
       endif
@@ -6309,7 +6305,7 @@ subroutine barotropic_init(u, v, h, Time, G, GV, US, param_file, diag, CS, &
   CS%id_vbtav = register_diag_field('ocean_model', 'vbtav', diag%axesCv1, Time, &
       'Barotropic time-average meridional velocity', 'm s-1', conversion=US%L_T_to_m_s)
   CS%id_eta_cor = register_diag_field('ocean_model', 'eta_cor', diag%axesT1, Time, &
-      'Corrective mass flux within a timestep', 'm', conversion=GV%H_to_m)
+      'Corrective mass or volume flux within a timestep', thickness_units, conversion=GV%H_to_MKS)
   CS%id_visc_rem_u = register_diag_field('ocean_model', 'visc_rem_u', diag%axesCuL, Time, &
       'Viscous remnant at u', 'nondim')
   CS%id_visc_rem_v = register_diag_field('ocean_model', 'visc_rem_v', diag%axesCvL, Time, &
@@ -6434,18 +6430,19 @@ subroutine barotropic_init(u, v, h, Time, G, GV, US, param_file, diag, CS, &
   ! Calculate other constants which are used for btstep.
 
   if (.not.CS%nonlin_stress) then
-    Mean_SL = G%Z_ref
     Z_to_H = GV%Z_to_H ; if (.not.GV%Boussinesq) Z_to_H = GV%RZ_to_H * CS%Rho_BT_lin
     do j=js,je ; do I=is-1,ie
-      if (G%OBCmaskCu(I,j) > 0.) then
-        CS%IDatu(I,j) = G%OBCmaskCu(I,j) * 2.0 / (Z_to_H * ((G%bathyT(i+1,j) + G%bathyT(i,j)) + 2.0*Mean_SL))
+      htot = max(G%meanSL(i+1,j) + G%bathyT(i+1,j), 0.0) + max(G%meanSL(i,j) + G%bathyT(i,j), 0.0)
+      if (G%OBCmaskCu(I,j) * htot > 0.) then
+        CS%IDatu(I,j) = G%OBCmaskCu(I,j) * 2.0 / (Z_to_H * htot)
       else ! Both neighboring H points are masked out or this is an OBC face so IDatu(I,j) is unused
         CS%IDatu(I,j) = 0.
       endif
     enddo ; enddo
     do J=js-1,je ; do i=is,ie
-      if (G%OBCmaskCv(i,J) > 0.) then
-        CS%IDatv(i,J) = G%OBCmaskCv(i,J) * 2.0 / (Z_to_H * ((G%bathyT(i,j+1) + G%bathyT(i,j)) + 2.0*Mean_SL))
+      htot = max(G%meanSL(i,j+1) + G%bathyT(i,j+1), 0.0) + max(G%meanSL(i,j) + G%bathyT(i,j), 0.0)
+      if (G%OBCmaskCv(i,J) * htot > 0.) then
+        CS%IDatv(i,J) = G%OBCmaskCv(i,J) * 2.0 / (Z_to_H * htot)
       else ! Both neighboring H points are masked out or this is an OBC face so IDatv(i,J) is unused
         CS%IDatv(i,J) = 0.
       endif
diff --git a/src/core/MOM_check_scaling.F90 b/src/core/MOM_check_scaling.F90
index 2841514924..07db537c64 100644
--- a/src/core/MOM_check_scaling.F90
+++ b/src/core/MOM_check_scaling.F90
@@ -126,7 +126,7 @@ subroutine compose_dimension_list(ns, des, wts)
   call add_scaling(ns, des, wts, "[S H ~> ppt m or ppt kg m-2]", 8) ! Depth integrated salinity
   call add_scaling(ns, des, wts, "[Z2 T-2 ~> m2 s-2]", 8)     ! Turbulent kinetic energy
   call add_scaling(ns, des, wts, "[R L2 Z T-2 ~> Pa m]", 7)   ! Vertically integrated pressure anomalies
-  call add_scaling(ns, des, wts, "[Z2 T-1 / Z3 T-3 = T2 Z-1 ~> s2 m-1]", 7) ! (TKE_to_Kd)
+  call add_scaling(ns, des, wts, "[T2 Z-1 ~> s2 m-1]", 7)     ! (TKE_to_Kd)
   call add_scaling(ns, des, wts, "[L4 T-1 ~> m4 s-1]", 7)     ! Biharmonic viscosity
   call add_scaling(ns, des, wts, "[L3 ~> m3]", 7)             ! Metric dependent constants for viscosity
   call add_scaling(ns, des, wts, "[L2 T-3 ~> m2 s-3]", 7)     ! Buoyancy flux or MEKE sources [L2 T-3 ~> W kg-1]
diff --git a/src/core/MOM_continuity_PPM.F90 b/src/core/MOM_continuity_PPM.F90
index d5e380391c..7e9bfe88ac 100644
--- a/src/core/MOM_continuity_PPM.F90
+++ b/src/core/MOM_continuity_PPM.F90
@@ -49,6 +49,9 @@ module MOM_continuity_PPM
                              !! discrepancies between the barotropic solution and
                              !! the sum of the layer thicknesses [L T-1 ~> m s-1].
   real :: CFL_limit_adjust   !< The maximum CFL of the adjusted velocities [nondim]
+  real :: h_marg_min         !< Negligible floor on h_marg, the marginal thickness
+                             !! used to calculate the partial derivative of transports
+                             !! with velocities [H ~> m or kg m-2]
   logical :: aggress_adjust  !< If true, allow the adjusted velocities to have a
                              !! relative CFL change up to 0.5.  False by default.
   logical :: vol_CFL         !< If true, use the ratio of the open face lengths
@@ -625,7 +628,8 @@ subroutine zonal_mass_flux(u, h_in, h_W, h_E, uh, dt, G, GV, US, CS, OBC, por_fa
       enddo ; endif
       call zonal_flux_layer(u(:,j,k), h_in(:,j,k), h_W(:,j,k), h_E(:,j,k), &
                             uh(:,j,k), duhdu(:,k), visc_rem(:,k), &
-                            dt, G, US, j, ish, ieh, do_I, CS%vol_CFL, por_face_areaU(:,j,k), OBC)
+                            dt, G, US, j, ish, ieh, do_I, CS%vol_CFL, por_face_areaU(:,j,k), &
+                            CS%h_marg_min, OBC)
       if (local_specified_BC) then
         do I=ish-1,ieh ; if (OBC%segnum_u(I,j) /= 0) then
           l_seg = abs(OBC%segnum_u(I,j))
@@ -875,7 +879,8 @@ subroutine zonal_BT_mass_flux(u, h_in, h_W, h_E, uhbt, dt, G, GV, US, CS, OBC, p
     do k=1,nz
       ! This sets uh and duhdu.
       call zonal_flux_layer(u(:,j,k), h_in(:,j,k), h_W(:,j,k), h_E(:,j,k), uh, duhdu, ones, &
-                            dt, G, US, j, ish, ieh, do_I, CS%vol_CFL, por_face_areaU(:,j,k), OBC)
+                            dt, G, US, j, ish, ieh, do_I, CS%vol_CFL, por_face_areaU(:,j,k), &
+                            CS%h_marg_min, OBC)
       if (OBC_in_row) then ; do I=ish-1,ieh ; if (OBC%segnum_u(I,j) /= 0) then
         l_seg = abs(OBC%segnum_u(I,j))
         if (OBC%segment(l_seg)%specified) uh(I) = OBC%segment(l_seg)%normal_trans(I,j,k)
@@ -894,7 +899,7 @@ end subroutine zonal_BT_mass_flux
 
 !> Evaluates the zonal mass or volume fluxes in a layer.
 subroutine zonal_flux_layer(u, h, h_W, h_E, uh, duhdu, visc_rem, dt, G, US, j, &
-                            ish, ieh, do_I, vol_CFL, por_face_areaU, OBC)
+                            ish, ieh, do_I, vol_CFL, por_face_areaU, h_marg_min, OBC)
   type(ocean_grid_type),        intent(in)    :: G        !< Ocean's grid structure.
   real, dimension(SZIB_(G)),    intent(in)    :: u        !< Zonal velocity [L T-1 ~> m s-1].
   real, dimension(SZIB_(G)),    intent(in)    :: visc_rem !< Both the fraction of the
@@ -918,13 +923,13 @@ subroutine zonal_flux_layer(u, h, h_W, h_E, uh, duhdu, visc_rem, dt, G, US, j, &
   logical,                      intent(in)    :: vol_CFL  !< If true, rescale the
   real, dimension(SZIB_(G)),    intent(in)    :: por_face_areaU !< fractional open area of U-faces [nondim]
           !! ratio of face areas to the cell areas when estimating the CFL number.
+  real,                         intent(in)    :: h_marg_min !< Negligible floor on h_marg [H ~> m or kg m-2]
   type(ocean_OBC_type), optional, pointer     :: OBC !< Open boundaries control structure.
   ! Local variables
   real :: CFL  ! The CFL number based on the local velocity and grid spacing [nondim]
   real :: curv_3 ! A measure of the thickness curvature over a grid length [H ~> m or kg m-2]
   real :: h_marg ! The marginal thickness of a flux [H ~> m or kg m-2].
   integer :: i
-  integer :: l_seg
   logical :: local_open_BC
 
   local_open_BC = .false.
@@ -952,6 +957,7 @@ subroutine zonal_flux_layer(u, h, h_W, h_E, uh, duhdu, visc_rem, dt, G, US, j, &
       uh(I) = 0.0
       h_marg = 0.5 * (h_W(i+1) + h_E(i))
     endif
+    h_marg = max(h_marg, h_marg_min)
     duhdu(I) = (G%dy_Cu(I,j) * por_face_areaU(I)) * h_marg * visc_rem(I)
   endif ; enddo
 
@@ -960,10 +966,10 @@ subroutine zonal_flux_layer(u, h, h_W, h_E, uh, duhdu, visc_rem, dt, G, US, j, &
       if (OBC%segment(abs(OBC%segnum_u(I,j)))%open) then
         if (OBC%segnum_u(I,j) > 0) then !  OBC_DIRECTION_E
           uh(I) = (G%dy_Cu(I,j) * por_face_areaU(I)) * u(I) * h(i)
-          duhdu(I) = (G%dy_Cu(I,j) * por_face_areaU(I)) * h(i) * visc_rem(I)
+          duhdu(I) = (G%dy_Cu(I,j) * por_face_areaU(I)) * max(h(i), h_marg_min) * visc_rem(I)
         else !  OBC_DIRECTION_W
           uh(I) = (G%dy_Cu(I,j) * por_face_areaU(I)) * u(I) * h(i+1)
-          duhdu(I) = (G%dy_Cu(I,j)* por_face_areaU(I)) * h(i+1) * visc_rem(I)
+          duhdu(I) = (G%dy_Cu(I,j)* por_face_areaU(I)) * max(h(i+1), h_marg_min) * visc_rem(I)
         endif
       endif
     endif ; endif ; enddo
@@ -1215,7 +1221,8 @@ subroutine zonal_flux_adjust(u, h_in, h_W, h_E, uhbt, uh_tot_0, duhdu_tot_0, &
       do I=ish-1,ieh ; u_new(I) = u(I,j,k) + du(I) * visc_rem(I,k) ; enddo
       call zonal_flux_layer(u_new, h_in(:,j,k), h_W(:,j,k), h_E(:,j,k), &
                             uh_aux(:,k), duhdu(:,k), visc_rem(:,k), &
-                            dt, G, US, j, ish, ieh, do_I, CS%vol_CFL, por_face_areaU(:,j,k), OBC)
+                            dt, G, US, j, ish, ieh, do_I, CS%vol_CFL, por_face_areaU(:,j,k), &
+                            CS%h_marg_min, OBC)
     enddo ; endif
 
     if (itt < max_itts) then
@@ -1363,11 +1370,14 @@ subroutine set_zonal_BT_cont(u, h_in, h_W, h_E, BT_cont, uh_tot_0, duhdu_tot_0,
       u_0(I) = u(I,j,k) + du0(I) * visc_rem(I,k)
     endif ; enddo
     call zonal_flux_layer(u_0, h_in(:,j,k), h_W(:,j,k), h_E(:,j,k), uh_0, duhdu_0, &
-                          visc_rem(:,k), dt, G, US, j, ish, ieh, do_I, CS%vol_CFL, por_face_areaU(:,j,k))
+                          visc_rem(:,k), dt, G, US, j, ish, ieh, do_I, CS%vol_CFL, &
+                          por_face_areaU(:,j,k), CS%h_marg_min)
     call zonal_flux_layer(u_L, h_in(:,j,k), h_W(:,j,k), h_E(:,j,k), uh_L, duhdu_L, &
-                          visc_rem(:,k), dt, G, US, j, ish, ieh, do_I, CS%vol_CFL, por_face_areaU(:,j,k))
+                          visc_rem(:,k), dt, G, US, j, ish, ieh, do_I, CS%vol_CFL, &
+                          por_face_areaU(:,j,k), CS%h_marg_min)
     call zonal_flux_layer(u_R, h_in(:,j,k), h_W(:,j,k), h_E(:,j,k), uh_R, duhdu_R, &
-                          visc_rem(:,k), dt, G, US, j, ish, ieh, do_I, CS%vol_CFL, por_face_areaU(:,j,k))
+                          visc_rem(:,k), dt, G, US, j, ish, ieh, do_I, CS%vol_CFL, &
+                          por_face_areaU(:,j,k), CS%h_marg_min)
     do I=ish-1,ieh ; if (do_I(I)) then
       FAmt_0(I) = FAmt_0(I) + duhdu_0(I)
       FAmt_L(I) = FAmt_L(I) + duhdu_L(I)
@@ -1518,7 +1528,8 @@ subroutine meridional_mass_flux(v, h_in, h_S, h_N, vh, dt, G, GV, US, CS, OBC, p
       enddo ; endif
       call merid_flux_layer(v(:,J,k), h_in(:,:,k), h_S(:,:,k), h_N(:,:,k), &
                             vh(:,J,k), dvhdv(:,k), visc_rem(:,k), &
-                            dt, G, US, J, ish, ieh, do_I, CS%vol_CFL, por_face_areaV(:,:,k), OBC)
+                            dt, G, US, J, ish, ieh, do_I, CS%vol_CFL, por_face_areaV(:,:,k), &
+                            CS%h_marg_min, OBC)
       if (local_specified_BC) then
         do i=ish,ieh ; if (OBC%segnum_v(i,J) /= 0) then
           l_seg = abs(OBC%segnum_v(i,J))
@@ -1765,7 +1776,8 @@ subroutine meridional_BT_mass_flux(v, h_in, h_S, h_N, vhbt, dt, G, GV, US, CS, O
     do k=1,nz
       ! This sets vh and dvhdv.
       call merid_flux_layer(v(:,J,k), h_in(:,:,k), h_S(:,:,k), h_N(:,:,k), vh, dvhdv, ones, &
-                            dt, G, US, J, ish, ieh, do_I, CS%vol_CFL, por_face_areaV(:,:,k), OBC)
+                            dt, G, US, J, ish, ieh, do_I, CS%vol_CFL, por_face_areaV(:,:,k), &
+                            CS%h_marg_min, OBC)
       if (OBC_in_row) then ; do i=ish,ieh ; if (OBC%segnum_v(i,J) /= 0) then
         l_seg = abs(OBC%segnum_v(i,J))
         if (OBC%segment(l_seg)%specified) vh(i) = OBC%segment(l_seg)%normal_trans(i,J,k)
@@ -1785,7 +1797,7 @@ end subroutine meridional_BT_mass_flux
 
 !> Evaluates the meridional mass or volume fluxes in a layer.
 subroutine merid_flux_layer(v, h, h_S, h_N, vh, dvhdv, visc_rem, dt, G, US, J, &
-                            ish, ieh, do_I, vol_CFL, por_face_areaV, OBC)
+                            ish, ieh, do_I, vol_CFL, por_face_areaV, h_marg_min, OBC)
   type(ocean_grid_type),        intent(in)    :: G        !< Ocean's grid structure.
   real, dimension(SZI_(G)),     intent(in)    :: v        !< Meridional velocity [L T-1 ~> m s-1].
   real, dimension(SZI_(G)),     intent(in)    :: visc_rem !< Both the fraction of the
@@ -1813,6 +1825,7 @@ subroutine merid_flux_layer(v, h, h_S, h_N, vh, dvhdv, visc_rem, dt, G, US, J, &
          !! ratio of face areas to the cell areas when estimating the CFL number.
   real, dimension(SZI_(G),SZJB_(G)), &
                              intent(in) :: por_face_areaV !< fractional open area of V-faces [nondim]
+  real,                         intent(in)    :: h_marg_min !< Negligible floor on h_marg [H ~> m or kg m-2]
   type(ocean_OBC_type), optional, pointer :: OBC !< Open boundaries control structure.
   ! Local variables
   real :: CFL ! The CFL number based on the local velocity and grid spacing [nondim]
@@ -1848,6 +1861,7 @@ subroutine merid_flux_layer(v, h, h_S, h_N, vh, dvhdv, visc_rem, dt, G, US, J, &
       vh(i) = 0.0
       h_marg = 0.5 * (h_S(i,j+1) + h_N(i,j))
     endif
+    h_marg = max(h_marg, h_marg_min)
     dvhdv(i) = (G%dx_Cv(i,J)*por_face_areaV(i,J)) * h_marg * visc_rem(i)
   endif ; enddo
 
@@ -1857,10 +1871,10 @@ subroutine merid_flux_layer(v, h, h_S, h_N, vh, dvhdv, visc_rem, dt, G, US, J, &
         if (OBC%segment(abs(OBC%segnum_v(i,J)))%open) then
           if (OBC%segnum_v(i,J) > 0) then !  OBC_DIRECTION_N
             vh(i) = (G%dx_Cv(i,J)*por_face_areaV(i,J)) * v(i) * h(i,j)
-            dvhdv(i) = (G%dx_Cv(i,J)*por_face_areaV(i,J)) * h(i,j) * visc_rem(i)
+            dvhdv(i) = (G%dx_Cv(i,J)*por_face_areaV(i,J)) * max(h(i,j), h_marg_min) * visc_rem(i)
           else
             vh(i) = (G%dx_Cv(i,J)*por_face_areaV(i,J)) * v(i) * h(i,j+1)
-            dvhdv(i) = (G%dx_Cv(i,J)*por_face_areaV(i,J)) * h(i,j+1) * visc_rem(i)
+            dvhdv(i) = (G%dx_Cv(i,J)*por_face_areaV(i,J)) * max(h(i,j+1), h_marg_min) * visc_rem(i)
           endif
         endif
       endif
@@ -2112,7 +2126,8 @@ subroutine meridional_flux_adjust(v, h_in, h_S, h_N, vhbt, vh_tot_0, dvhdv_tot_0
       do i=ish,ieh ; v_new(i) = v(i,J,k) + dv(i) * visc_rem(i,k) ; enddo
       call merid_flux_layer(v_new, h_in(:,:,k), h_S(:,:,k), h_N(:,:,k), &
                             vh_aux(:,k), dvhdv(:,k), visc_rem(:,k), &
-                            dt, G, US, J, ish, ieh, do_I, CS%vol_CFL, por_face_areaV(:,:,k), OBC)
+                            dt, G, US, J, ish, ieh, do_I, CS%vol_CFL, por_face_areaV(:,:,k), &
+                            CS%h_marg_min, OBC)
     enddo ; endif
 
     if (itt < max_itts) then
@@ -2260,11 +2275,14 @@ subroutine set_merid_BT_cont(v, h_in, h_S, h_N, BT_cont, vh_tot_0, dvhdv_tot_0,
       v_0(i) = v(I,j,k) + dv0(i) * visc_rem(i,k)
     endif ; enddo
     call merid_flux_layer(v_0, h_in(:,:,k), h_S(:,:,k), h_N(:,:,k), vh_0, dvhdv_0, &
-                          visc_rem(:,k), dt, G, US, J, ish, ieh, do_I, CS%vol_CFL, por_face_areaV(:,:,k))
+                          visc_rem(:,k), dt, G, US, J, ish, ieh, do_I, CS%vol_CFL, &
+                          por_face_areaV(:,:,k), CS%h_marg_min)
     call merid_flux_layer(v_L, h_in(:,:,k), h_S(:,:,k), h_N(:,:,k), vh_L, dvhdv_L, &
-                          visc_rem(:,k), dt, G, US, J, ish, ieh, do_I, CS%vol_CFL, por_face_areaV(:,:,k))
+                          visc_rem(:,k), dt, G, US, J, ish, ieh, do_I, CS%vol_CFL, &
+                          por_face_areaV(:,:,k), CS%h_marg_min)
     call merid_flux_layer(v_R, h_in(:,:,k), h_S(:,:,k), h_N(:,:,k), vh_R, dvhdv_R, &
-                          visc_rem(:,k), dt, G, US, J, ish, ieh, do_I, CS%vol_CFL, por_face_areaV(:,:,k))
+                          visc_rem(:,k), dt, G, US, J, ish, ieh, do_I, CS%vol_CFL, &
+                          por_face_areaV(:,:,k), CS%h_marg_min)
     do i=ish,ieh ; if (do_I(i)) then
       FAmt_0(i) = FAmt_0(i) + dvhdv_0(i)
       FAmt_L(i) = FAmt_L(i) + dvhdv_L(i)
@@ -2720,7 +2738,7 @@ subroutine continuity_PPM_init(Time, G, GV, US, param_file, diag, CS, OBC)
                   !! regulate diagnostic output.
   type(continuity_PPM_CS), intent(inout) :: CS   !< Module's control structure.
   type(ocean_OBC_type),    pointer       :: OBC  !< Open boundaries control structure.
-  logical :: local_open_BC
+  logical :: local_open_BC, use_h_marg_min
   type(OBC_segment_type), pointer :: segment => NULL()
   integer :: n
 
@@ -2793,12 +2811,22 @@ subroutine continuity_PPM_init(Time, G, GV, US, param_file, diag, CS, OBC)
                  "If true, use the marginal face areas from the continuity "//&
                  "solver for use as the weights in the barotropic solver. "//&
                  "Otherwise use the transport averaged areas.", default=.true.)
+  call get_param(param_file, mdl, "CONT_USE_H_MARG_MIN", use_h_marg_min, &
+                 "If true, the marginal thickness used and returned from continuity "//&
+                 "is bounded from below by a sub-roundoff value. Otherwise the "//&
+                 "minimum is 0.", default=.false.)
   CS%diag => diag
 
   id_clock_reconstruct = cpu_clock_id('(Ocean continuity reconstruction)', grain=CLOCK_ROUTINE)
   id_clock_update = cpu_clock_id('(Ocean continuity update)', grain=CLOCK_ROUTINE)
   id_clock_correct = cpu_clock_id('(Ocean continuity correction)', grain=CLOCK_ROUTINE)
 
+  if (use_h_marg_min) then
+    CS%h_marg_min = GV%H_subroundoff
+  else
+    CS%h_marg_min = 0.
+  endif
+
   if (local_open_BC) then
     do n=1, OBC%number_of_segments
       segment => OBC%segment(n)
diff --git a/src/core/MOM_dynamics_split_RK2b.F90 b/src/core/MOM_dynamics_split_RK2b.F90
index 9835c0c02e..192b9bc1c6 100644
--- a/src/core/MOM_dynamics_split_RK2b.F90
+++ b/src/core/MOM_dynamics_split_RK2b.F90
@@ -369,10 +369,10 @@ subroutine step_MOM_dyn_split_RK2b(u_av, v_av, h, tv, visc, Time_local, dt, forc
                                 ! saved for use in the Flather open boundary condition code [L T-1 ~> m s-1]
 
   ! GMM, TODO: make these allocatable?
-  real, dimension(SZIB_(G),SZJ_(G),SZK_(GV)) :: uold ! u-velocity before vert_visc is applied, for fpmix
-                                                     !                                      [L T-1 ~> m s-1]
-  real, dimension(SZI_(G),SZJB_(G),SZK_(GV)) :: vold ! v-velocity before vert_visc is applied, for fpmix
-                                                     !                                      [L T-1 ~> m s-1]
+  ! real, dimension(SZIB_(G),SZJ_(G),SZK_(GV)) :: uold ! u-velocity before vert_visc is applied, for fpmix
+  !                                                    !                                      [L T-1 ~> m s-1]
+  ! real, dimension(SZI_(G),SZJB_(G),SZK_(GV)) :: vold ! v-velocity before vert_visc is applied, for fpmix
+  !                                                    !                                      [L T-1 ~> m s-1]
   real :: pres_to_eta ! A factor that converts pressures to the units of eta
                       ! [H T2 R-1 L-2 ~> m Pa-1 or kg m-2 Pa-1]
   real, pointer, dimension(:,:) :: &
@@ -392,7 +392,7 @@ subroutine step_MOM_dyn_split_RK2b(u_av, v_av, h, tv, visc, Time_local, dt, forc
     uh_ptr => NULL(), &  ! A pointer to a zonal volume or mass transport [H L2 T-1 ~> m3 s-1 or kg s-1]
     vh_ptr => NULL()     ! A pointer to a meridional volume or mass transport [H L2 T-1 ~> m3 s-1 or kg s-1]
 
-  real, dimension(SZI_(G),SZJ_(G)) :: hbl       ! Boundary layer depth from Cvmix [H ~> m or kg m-2]
+  ! real, dimension(SZI_(G),SZJ_(G)) :: hbl       ! Boundary layer depth from Cvmix [H ~> m or kg m-2]
   real :: dt_pred   ! The time step for the predictor part of the baroclinic time stepping [T ~> s].
   real :: Idt_bc    ! Inverse of the baroclinic timestep [T-1 ~> s-1]
   logical :: dyn_p_surf
@@ -1186,7 +1186,6 @@ subroutine register_restarts_dyn_split_RK2b(HI, GV, US, param_file, CS, restart_
   real, dimension(SZI_(HI),SZJB_(HI),SZK_(GV)), &
                          target, intent(inout) :: vh !< merid volume or mass transport [H L2 T-1 ~> m3 s-1 or kg s-1]
 
-  character(len=40) :: mdl = "MOM_dynamics_split_RK2b" ! This module's name.
   type(vardesc)     :: vd(2)
   character(len=48) :: thickness_units, flux_units
 
@@ -1320,13 +1319,11 @@ subroutine initialize_dyn_split_RK2b(u, v, h, tv, uh, vh, eta, Time, G, GV, US,
                                                                 !! solver and Coriolis scheme.
 
   ! local variables
-  real, dimension(SZI_(G),SZJ_(G),SZK_(GV)) :: h_tmp ! A temporary copy of the layer thicknesses [H ~> m or kg m-2]
   character(len=40) :: mdl = "MOM_dynamics_split_RK2b" ! This module's name.
   ! This include declares and sets the variable "version".
 # include "version_variable.h"
   character(len=48) :: thickness_units, flux_units, eta_rest_name
   logical :: debug_truncations
-  logical :: read_uv, read_h2
   logical :: enable_bugs  ! If true, the defaults for recently added bug-fix flags are set to
                           ! recreate the bugs, or if false bugs are only used if actively selected.
   logical :: visc_rem_bug ! Stores the value of runtime paramter VISC_REM_BUG.
diff --git a/src/core/MOM_forcing_type.F90 b/src/core/MOM_forcing_type.F90
index f51ec928b6..6d36ab155d 100644
--- a/src/core/MOM_forcing_type.F90
+++ b/src/core/MOM_forcing_type.F90
@@ -1186,7 +1186,7 @@ subroutine find_ustar_fluxes(fluxes, tv, U_star, G, GV, US, halo, H_T_units)
                        ! density [H2 Z-2 R-1 ~> m3 kg-1 or kg m-3]
   logical :: Z_T_units ! If true, U_star is returned in units of [Z T-1 ~> m s-1], otherwise it is
                        ! returned in [H T-1 ~> m s-1 or kg m-2 s-1]
-  integer :: i, j, k, is, ie, js, je, hs
+  integer :: i, j, is, ie, js, je, hs
 
   hs = 0 ; if (present(halo)) hs = max(halo, 0)
   is = G%isc - hs ; ie = G%iec + hs ; js = G%jsc - hs ; je = G%jec + hs
@@ -1251,7 +1251,7 @@ subroutine find_ustar_mech_forcing(forces, tv, U_star, G, GV, US, halo, H_T_unit
                        ! the rescaled reference density [H2 Z-2 R-1 ~> m3 kg-1 or kg m-3]
   logical :: Z_T_units ! If true, U_star is returned in units of [Z T-1 ~> m s-1], otherwise it is
                        ! returned in [H T-1 ~> m s-1 or kg m-2 s-1]
-  integer :: i, j, k, is, ie, js, je, hs
+  integer :: i, j, is, ie, js, je, hs
 
   hs = 0 ; if (present(halo)) hs = max(halo, 0)
   is = G%isc - hs ; ie = G%iec + hs ; js = G%jsc - hs ; je = G%jec + hs
diff --git a/src/core/MOM_grid.F90 b/src/core/MOM_grid.F90
index 94583673c2..d5d319dc47 100644
--- a/src/core/MOM_grid.F90
+++ b/src/core/MOM_grid.F90
@@ -95,6 +95,7 @@ module MOM_grid
     geoLonCu, &  !< The geographic longitude at u points [degrees_E] or [km] or [m].
     dxCu, &      !< dxCu is delta x at u points [L ~> m].
     IdxCu, &     !< 1/dxCu [L-1 ~> m-1].
+    IdxCu_OBCmask, & !< 1/dxCu or 0 at boundary or OBC points [L-1 ~> m-1].
     dyCu, &      !< dyCu is delta y at u points [L ~> m].
     IdyCu, &     !< 1/dyCu [L-1 ~> m-1].
     dy_Cu, &     !< The unblocked lengths of the u-faces of the h-cell [L ~> m].
@@ -110,6 +111,7 @@ module MOM_grid
     IdxCv, &     !< 1/dxCv [L-1 ~> m-1].
     dyCv, &      !< dyCv is delta y at v points [L ~> m].
     IdyCv, &     !< 1/dyCv [L-1 ~> m-1].
+    IdyCv_OBCmask, & !< 1/dxCv or 0 at boundary or OBC points [L-1 ~> m-1].
     dx_Cv, &     !< The unblocked lengths of the v-faces of the h-cell [L ~> m].
     IareaCv, &   !< The masked inverse areas of v-grid cells [L-2 ~> m-2].
     areaCv       !< The areas of the v-grid cells [L2 ~> m2].
@@ -158,7 +160,16 @@ module MOM_grid
     y_ax_unit_short     !< A short description of the y-axis units for documenting parameter units
 
   real ALLOCABLE_, dimension(NIMEM_,NJMEM_) :: &
-    bathyT           !< Ocean bottom depth at tracer points, in depth units [Z ~> m].
+    bathyT           !< Ocean bottom depth, referenced to Z_ref at tracer points. bathyT is in
+                     !! depth units and positive *below* Z_ref [Z ~> m].
+  real ALLOCABLE_, dimension(NIMEM_,NJMEM_) :: &
+    meanSL           !< Spatially varying time mean sea level, referenced to Z_ref at tracer points.
+                     !! meanSL is in height units and positive *above* Z_ref. It is used
+                     !! a) as the height where p = p_atm or zero;
+                     !! b) to calculate time mean thickness of the water column, where
+                     !!    mean thickness = max(meanSL + bathyT, 0.0).
+                     !! meanSL is 2D for the consideration of a domain with spatically varying mean
+                     !! height, e.g. the Great Lakes system [Z ~> m].
   real    :: Z_ref   !< A reference value for all geometric height fields, such as bathyT [Z ~> m].
 
   logical :: bathymetry_at_vel  !< If true, there are separate values for the
@@ -433,6 +444,7 @@ subroutine set_derived_metrics(G, US)
     if (G%dyCu(I,j) < 0.0) G%dyCu(I,j) = 0.0
     G%IdxCu(I,j) = Adcroft_reciprocal(G%dxCu(I,j))
     G%IdyCu(I,j) = Adcroft_reciprocal(G%dyCu(I,j))
+    G%IdxCu_OBCmask(I,j) = G%OBCmaskCu(I,j) * G%IdxCu(I,j) ! This may be reset if masks are reset.
   enddo ; enddo
 
   do J=JsdB,JedB ; do i=isd,ied
@@ -440,6 +452,7 @@ subroutine set_derived_metrics(G, US)
     if (G%dyCv(i,J) < 0.0) G%dyCv(i,J) = 0.0
     G%IdxCv(i,J) = Adcroft_reciprocal(G%dxCv(i,J))
     G%IdyCv(i,J) = Adcroft_reciprocal(G%dyCv(i,J))
+    G%IdyCv_OBCmask(i,J) = G%OBCmaskCv(i,J) * G%IdyCv(i,J) ! This may be reset if masks are reset.
   enddo ; enddo
 
   do J=JsdB,JedB ; do I=IsdB,IedB
@@ -535,6 +548,7 @@ subroutine allocate_metrics(G)
   ALLOC_(G%dxBu(IsdB:IedB,JsdB:JedB))  ; G%dxBu(:,:) = 0.0
   ALLOC_(G%IdxT(isd:ied,jsd:jed))      ; G%IdxT(:,:) = 0.0
   ALLOC_(G%IdxCu(IsdB:IedB,jsd:jed))   ; G%IdxCu(:,:) = 0.0
+  ALLOC_(G%IdxCu_OBCmask(IsdB:IedB,jsd:jed)) ; G%IdxCu_OBCmask(:,:) = 0.0
   ALLOC_(G%IdxCv(isd:ied,JsdB:JedB))   ; G%IdxCv(:,:) = 0.0
   ALLOC_(G%IdxBu(IsdB:IedB,JsdB:JedB)) ; G%IdxBu(:,:) = 0.0
 
@@ -545,6 +559,7 @@ subroutine allocate_metrics(G)
   ALLOC_(G%IdyT(isd:ied,jsd:jed))      ; G%IdyT(:,:) = 0.0
   ALLOC_(G%IdyCu(IsdB:IedB,jsd:jed))   ; G%IdyCu(:,:) = 0.0
   ALLOC_(G%IdyCv(isd:ied,JsdB:JedB))   ; G%IdyCv(:,:) = 0.0
+  ALLOC_(G%IdyCv_OBCmask(isd:ied,JsdB:JedB)) ; G%IdyCv_OBCmask(:,:) = 0.0
   ALLOC_(G%IdyBu(IsdB:IedB,JsdB:JedB)) ; G%IdyBu(:,:) = 0.0
 
   ALLOC_(G%areaT(isd:ied,jsd:jed))       ; G%areaT(:,:) = 0.0
@@ -584,6 +599,7 @@ subroutine allocate_metrics(G)
   ALLOC_(G%IareaCv(isd:ied,JsdB:JedB)) ; G%IareaCv(:,:) = 0.0
 
   ALLOC_(G%bathyT(isd:ied, jsd:jed)) ; G%bathyT(:,:) = -G%Z_ref
+  ALLOC_(G%meanSL(isd:ied, jsd:jed)) ; G%meanSL(:,:) = G%Z_ref
   ALLOC_(G%CoriolisBu(IsdB:IedB, JsdB:JedB)) ; G%CoriolisBu(:,:) = 0.0
   ALLOC_(G%Coriolis2Bu(IsdB:IedB, JsdB:JedB)) ; G%Coriolis2Bu(:,:) = 0.0
   ALLOC_(G%dF_dx(isd:ied, jsd:jed)) ; G%dF_dx(:,:) = 0.0
@@ -616,6 +632,8 @@ subroutine MOM_grid_end(G)
   DEALLOC_(G%dyT)  ; DEALLOC_(G%dyCu)  ; DEALLOC_(G%dyCv)  ; DEALLOC_(G%dyBu)
   DEALLOC_(G%IdyT) ; DEALLOC_(G%IdyCu) ; DEALLOC_(G%IdyCv) ; DEALLOC_(G%IdyBu)
 
+  DEALLOC_(G%IdxCu_OBCmask) ; DEALLOC_(G%IdyCv_OBCmask)
+
   DEALLOC_(G%areaT)  ; DEALLOC_(G%IareaT)
   DEALLOC_(G%areaBu) ; DEALLOC_(G%IareaBu)
   DEALLOC_(G%areaCu) ; DEALLOC_(G%IareaCu)
@@ -631,9 +649,10 @@ subroutine MOM_grid_end(G)
 
   DEALLOC_(G%dx_Cv) ; DEALLOC_(G%dy_Cu)
 
-  DEALLOC_(G%bathyT)  ; DEALLOC_(G%CoriolisBu) ; DEALLOC_(G%Coriolis2Bu)
-  DEALLOC_(G%dF_dx)   ; DEALLOC_(G%dF_dy)
-  DEALLOC_(G%sin_rot) ; DEALLOC_(G%cos_rot)
+  DEALLOC_(G%bathyT)     ; DEALLOC_(G%meanSL)
+  DEALLOC_(G%CoriolisBu) ; DEALLOC_(G%Coriolis2Bu)
+  DEALLOC_(G%dF_dx)      ; DEALLOC_(G%dF_dy)
+  DEALLOC_(G%sin_rot)    ; DEALLOC_(G%cos_rot)
 
   DEALLOC_(G%porous_DminU) ; DEALLOC_(G%porous_DmaxU) ; DEALLOC_(G%porous_DavgU)
   DEALLOC_(G%porous_DminV) ; DEALLOC_(G%porous_DmaxV) ; DEALLOC_(G%porous_DavgV)
diff --git a/src/core/MOM_interface_heights.F90 b/src/core/MOM_interface_heights.F90
index c9e4bc015e..5a66b4375e 100644
--- a/src/core/MOM_interface_heights.F90
+++ b/src/core/MOM_interface_heights.F90
@@ -480,7 +480,7 @@ subroutine find_rho_bottom(G, GV, US, tv, h, dz, pres_int, dz_avg, j, Rho_bot, h
   ! Local variables
   real :: hb(SZI_(G))         ! Running sum of the thickness in the bottom boundary layer [H ~> m or kg m-2]
   real :: SpV_h_bot(SZI_(G))  ! Running sum of the specific volume times thickness in the bottom
-                              ! boundary layer [R-1 H ~> m4 kg-1 or m]
+                              ! boundary layer [H R-1 ~> m4 kg-1 or m]
   real :: dz_bbl_rem(SZI_(G)) ! Vertical extent of the boundary layer that has yet to be accounted
                               ! for [Z ~> m]
   real :: h_bbl_frac(SZI_(G)) ! Thickness of the fractional layer that makes up the top of the
diff --git a/src/core/MOM_open_boundary.F90 b/src/core/MOM_open_boundary.F90
index 2ebbce6475..e8f5f13334 100644
--- a/src/core/MOM_open_boundary.F90
+++ b/src/core/MOM_open_boundary.F90
@@ -506,6 +506,7 @@ subroutine open_boundary_config(G, US, param_file, OBC)
   type(ocean_OBC_type),    pointer       :: OBC !< Open boundary control structure
 
   ! Local variables
+  integer :: num_of_segs ! Number of open boundary segments
   integer :: n, n_seg ! For looping over segments
   logical :: debug, mask_outside, reentrant_x, reentrant_y
   character(len=15) :: segment_param_str ! The run-time parameter name for each segment
@@ -513,26 +514,24 @@ subroutine open_boundary_config(G, US, param_file, OBC)
   character(len=200) :: config1          ! String for OBC_USER_CONFIG
   real               :: Lscale_in, Lscale_out ! parameters controlling tracer values at the boundaries [L ~> m]
   integer :: default_answer_date  ! The default setting for the various ANSWER_DATE flags.
-  logical :: check_remapping, force_bounds_in_subcell
   logical :: enable_bugs     ! If true, the defaults for recently added bug-fix flags are set to
                              ! recreate the bugs, or if false bugs are only used if actively selected.
   logical :: debugging_tests ! If true, do additional calls resetting values to help debug the performance
                              ! of the open boundary condition code.
-  logical :: om4_remap_via_sub_cells ! If true, use the OM4 remapping algorithm
   ! This include declares and sets the variable "version".
 # include "version_variable.h"
 
-  allocate(OBC)
+  call log_version(param_file, mdl, version, "Controls where open boundaries are located, "//&
+                   "what kind of boundary condition to impose, and what data to apply, if any.", &
+                   all_default=.false.)
+  ! Parameter OBC_NUMBER_OF_SEGMENTS is always logged.
+  call get_param(param_file, mdl, "OBC_NUMBER_OF_SEGMENTS", num_of_segs, &
+                 "The number of open boundary segments.", default=0)
+  if (num_of_segs <= 0) & ! Do nothing if there is no OBC segments
+    return
 
-  call get_param(param_file, mdl, "OBC_NUMBER_OF_SEGMENTS", OBC%number_of_segments, &
-                 default=0, do_not_log=.true.)
-  call log_version(param_file, mdl, version, &
-                 "Controls where open boundaries are located, what kind of boundary condition "//&
-                 "to impose, and what data to apply, if any.", &
-                 all_default=(OBC%number_of_segments<=0))
-  call get_param(param_file, mdl, "OBC_NUMBER_OF_SEGMENTS", OBC%number_of_segments, &
-                 "The number of open boundary segments.", &
-                 default=0)
+  allocate(OBC)
+  OBC%number_of_segments = num_of_segs
   call get_param(param_file, mdl, "OBC_USER_CONFIG", config1, &
                  "A string that sets how the open boundary conditions are "//&
                  " configured: \n", default="none", do_not_log=.true.)
@@ -541,313 +540,302 @@ subroutine open_boundary_config(G, US, param_file, OBC)
 
   if (config1 /= "none" .and. config1 /= "dyed_obcs") OBC%user_BCs_set_globally = .true.
 
-  if (OBC%number_of_segments > 0) then
-    call get_param(param_file, mdl, "OBC_ZERO_VORTICITY", OBC%zero_vorticity, &
-         "If true, sets relative vorticity to zero on open boundaries.", &
-         default=.false.)
-    call get_param(param_file, mdl, "OBC_FREESLIP_VORTICITY", OBC%freeslip_vorticity, &
-         "If true, sets the normal gradient of tangential velocity to "//&
-         "zero in the relative vorticity on open boundaries. This cannot "//&
-         "be true if another OBC_XXX_VORTICITY option is True.", default=.true.)
-    call get_param(param_file, mdl, "OBC_COMPUTED_VORTICITY", OBC%computed_vorticity, &
-         "If true, uses the external values of tangential velocity "//&
-         "in the relative vorticity on open boundaries. This cannot "//&
-         "be true if another OBC_XXX_VORTICITY option is True.", default=.false.)
-    call get_param(param_file, mdl, "OBC_SPECIFIED_VORTICITY", OBC%specified_vorticity, &
-         "If true, uses the external values of tangential velocity "//&
-         "in the relative vorticity on open boundaries. This cannot "//&
-         "be true if another OBC_XXX_VORTICITY option is True.", default=.false.)
-    if ((OBC%zero_vorticity .and. OBC%freeslip_vorticity) .or.  &
-        (OBC%zero_vorticity .and. OBC%computed_vorticity) .or.  &
-        (OBC%zero_vorticity .and. OBC%specified_vorticity) .or.  &
-        (OBC%freeslip_vorticity .and. OBC%computed_vorticity) .or.  &
-        (OBC%freeslip_vorticity .and. OBC%specified_vorticity) .or.  &
-        (OBC%computed_vorticity .and. OBC%specified_vorticity))  &
-         call MOM_error(FATAL, "MOM_open_boundary.F90, open_boundary_config:\n"//&
-         "Only one of OBC_ZERO_VORTICITY, OBC_FREESLIP_VORTICITY, OBC_COMPUTED_VORTICITY\n"//&
-         "and OBC_IMPORTED_VORTICITY can be True at once.")
-    call get_param(param_file, mdl, "OBC_ZERO_STRAIN", OBC%zero_strain, &
-         "If true, sets the strain used in the stress tensor to zero on open boundaries.", &
-         default=.false.)
-    call get_param(param_file, mdl, "OBC_FREESLIP_STRAIN", OBC%freeslip_strain, &
-         "If true, sets the normal gradient of tangential velocity to "//&
-         "zero in the strain use in the stress tensor on open boundaries. This cannot "//&
-         "be true if another OBC_XXX_STRAIN option is True.", default=.true.)
-    call get_param(param_file, mdl, "OBC_COMPUTED_STRAIN", OBC%computed_strain, &
-         "If true, sets the normal gradient of tangential velocity to "//&
-         "zero in the strain use in the stress tensor on open boundaries. This cannot "//&
-         "be true if another OBC_XXX_STRAIN option is True.", default=.false.)
-    call get_param(param_file, mdl, "OBC_SPECIFIED_STRAIN", OBC%specified_strain, &
-         "If true, sets the normal gradient of tangential velocity to "//&
-         "zero in the strain use in the stress tensor on open boundaries. This cannot "//&
-         "be true if another OBC_XXX_STRAIN option is True.", default=.false.)
-    if ((OBC%zero_strain .and. OBC%freeslip_strain) .or.  &
-        (OBC%zero_strain .and. OBC%computed_strain) .or.  &
-        (OBC%zero_strain .and. OBC%specified_strain) .or.  &
-        (OBC%freeslip_strain .and. OBC%computed_strain) .or.  &
-        (OBC%freeslip_strain .and. OBC%specified_strain) .or.  &
-        (OBC%computed_strain .and. OBC%specified_strain))  &
-         call MOM_error(FATAL, "MOM_open_boundary.F90, open_boundary_config: \n"//&
-         "Only one of OBC_ZERO_STRAIN, OBC_FREESLIP_STRAIN, OBC_COMPUTED_STRAIN \n"//&
-         "and OBC_IMPORTED_STRAIN can be True at once.")
-    call get_param(param_file, mdl, "OBC_ZERO_BIHARMONIC", OBC%zero_biharmonic, &
-         "If true, zeros the Laplacian of flow on open boundaries in the biharmonic "//&
-         "viscosity term.", default=.false.)
-    call get_param(param_file, mdl, "MASK_OUTSIDE_OBCS", mask_outside, &
-         "If true, set the areas outside open boundaries to be land.", &
-         default=.false.)
-    call get_param(param_file, mdl, "RAMP_OBCS", OBC%ramp, &
-         "If true, ramps from zero to the external values over time, with"//&
-         "a ramping timescale given by RAMP_TIMESCALE. Ramping SSH only so far", &
-         default=.false.)
-    call get_param(param_file, mdl, "OBC_RAMP_TIMESCALE", OBC%ramp_timescale, &
-         "If RAMP_OBCS is true, this sets the ramping timescale.", &
-         units="days", default=1.0, scale=86400.0*US%s_to_T)
-    call get_param(param_file, mdl, "OBC_TIDE_N_CONSTITUENTS", OBC%n_tide_constituents, &
-         "Number of tidal constituents being added to the open boundary.", &
-         default=0)
-
-    if (OBC%n_tide_constituents > 0) then
-      OBC%add_tide_constituents = .true.
-    else
-      OBC%add_tide_constituents = .false.
-    endif
-
-    call get_param(param_file, mdl, "DEBUG", debug, default=.false.)
-    call get_param(param_file, mdl, "DEBUG_OBCS", OBC%debug, &
+  call get_param(param_file, mdl, "OBC_ZERO_VORTICITY", OBC%zero_vorticity, &
+       "If true, sets relative vorticity to zero on open boundaries.", &
+       default=.false.)
+  call get_param(param_file, mdl, "OBC_FREESLIP_VORTICITY", OBC%freeslip_vorticity, &
+       "If true, sets the normal gradient of tangential velocity to "//&
+       "zero in the relative vorticity on open boundaries. This cannot "//&
+       "be true if another OBC_XXX_VORTICITY option is True.", default=.true.)
+  call get_param(param_file, mdl, "OBC_COMPUTED_VORTICITY", OBC%computed_vorticity, &
+       "If true, uses the external values of tangential velocity "//&
+       "in the relative vorticity on open boundaries. This cannot "//&
+       "be true if another OBC_XXX_VORTICITY option is True.", default=.false.)
+  call get_param(param_file, mdl, "OBC_SPECIFIED_VORTICITY", OBC%specified_vorticity, &
+       "If true, uses the external values of tangential velocity "//&
+       "in the relative vorticity on open boundaries. This cannot "//&
+       "be true if another OBC_XXX_VORTICITY option is True.", default=.false.)
+  if ((OBC%zero_vorticity .and. OBC%freeslip_vorticity) .or.  &
+      (OBC%zero_vorticity .and. OBC%computed_vorticity) .or.  &
+      (OBC%zero_vorticity .and. OBC%specified_vorticity) .or.  &
+      (OBC%freeslip_vorticity .and. OBC%computed_vorticity) .or.  &
+      (OBC%freeslip_vorticity .and. OBC%specified_vorticity) .or.  &
+      (OBC%computed_vorticity .and. OBC%specified_vorticity))  &
+    call MOM_error(FATAL, "MOM_open_boundary.F90, open_boundary_config:\n"//&
+    "Only one of OBC_ZERO_VORTICITY, OBC_FREESLIP_VORTICITY, OBC_COMPUTED_VORTICITY\n"//&
+    "and OBC_IMPORTED_VORTICITY can be True at once.")
+  call get_param(param_file, mdl, "OBC_ZERO_STRAIN", OBC%zero_strain, &
+       "If true, sets the strain used in the stress tensor to zero on open boundaries.", &
+       default=.false.)
+  call get_param(param_file, mdl, "OBC_FREESLIP_STRAIN", OBC%freeslip_strain, &
+       "If true, sets the normal gradient of tangential velocity to "//&
+       "zero in the strain use in the stress tensor on open boundaries. This cannot "//&
+       "be true if another OBC_XXX_STRAIN option is True.", default=.true.)
+  call get_param(param_file, mdl, "OBC_COMPUTED_STRAIN", OBC%computed_strain, &
+       "If true, sets the normal gradient of tangential velocity to "//&
+       "zero in the strain use in the stress tensor on open boundaries. This cannot "//&
+       "be true if another OBC_XXX_STRAIN option is True.", default=.false.)
+  call get_param(param_file, mdl, "OBC_SPECIFIED_STRAIN", OBC%specified_strain, &
+       "If true, sets the normal gradient of tangential velocity to "//&
+       "zero in the strain use in the stress tensor on open boundaries. This cannot "//&
+       "be true if another OBC_XXX_STRAIN option is True.", default=.false.)
+  if ((OBC%zero_strain .and. OBC%freeslip_strain) .or.  &
+      (OBC%zero_strain .and. OBC%computed_strain) .or.  &
+      (OBC%zero_strain .and. OBC%specified_strain) .or.  &
+      (OBC%freeslip_strain .and. OBC%computed_strain) .or.  &
+      (OBC%freeslip_strain .and. OBC%specified_strain) .or.  &
+      (OBC%computed_strain .and. OBC%specified_strain))  &
+    call MOM_error(FATAL, "MOM_open_boundary.F90, open_boundary_config: \n"//&
+    "Only one of OBC_ZERO_STRAIN, OBC_FREESLIP_STRAIN, OBC_COMPUTED_STRAIN \n"//&
+    "and OBC_IMPORTED_STRAIN can be True at once.")
+  call get_param(param_file, mdl, "OBC_ZERO_BIHARMONIC", OBC%zero_biharmonic, &
+       "If true, zeros the Laplacian of flow on open boundaries in the biharmonic "//&
+       "viscosity term.", default=.false.)
+  call get_param(param_file, mdl, "MASK_OUTSIDE_OBCS", mask_outside, &
+       "If true, set the areas outside open boundaries to be land.", &
+       default=.false.)
+  call get_param(param_file, mdl, "RAMP_OBCS", OBC%ramp, &
+       "If true, ramps from zero to the external values over time, with"//&
+       "a ramping timescale given by RAMP_TIMESCALE. Ramping SSH only so far", &
+       default=.false.)
+  call get_param(param_file, mdl, "OBC_RAMP_TIMESCALE", OBC%ramp_timescale, &
+       "If RAMP_OBCS is true, this sets the ramping timescale.", &
+       units="days", default=1.0, scale=86400.0*US%s_to_T)
+  call get_param(param_file, mdl, "OBC_TIDE_N_CONSTITUENTS", OBC%n_tide_constituents, &
+       "Number of tidal constituents being added to the open boundary.", &
+       default=0)
+  OBC%add_tide_constituents = (OBC%n_tide_constituents > 0)
+
+  call get_param(param_file, mdl, "DEBUG", debug, default=.false.)
+  call get_param(param_file, mdl, "DEBUG_OBCS", OBC%debug, &
                  "If true, do additional calls to help debug the performance "//&
                  "of the open boundary condition code.", &
                  default=.false., debuggingParam=.true.)
-    if (OBC%debug .and. (num_PEs() > 1)) &
-      call MOM_error(FATAL, "DEBUG_OBCS = True is currently only supported for single PE runs.")
-    call get_param(param_file, mdl, "OBC_DEBUGGING_TESTS", debugging_tests, &
+  if (OBC%debug .and. (num_PEs() > 1)) &
+    call MOM_error(FATAL, "DEBUG_OBCS = True is currently only supported for single PE runs.")
+  call get_param(param_file, mdl, "OBC_DEBUGGING_TESTS", debugging_tests, &
                  "If true, do additional calls resetting certain values to help verify the correctness "//&
                  "of the open boundary condition code.", &
                  default=.false., old_name="DEBUG_OBC", debuggingParam=.true.)
-    call get_param(param_file, mdl, "NK_OBC_DEBUG", OBC%nk_OBC_debug, &
+  call get_param(param_file, mdl, "NK_OBC_DEBUG", OBC%nk_OBC_debug, &
                  "The number of layers of OBC segment data to write out in full "//&
                  "when DEBUG_OBCS is true.", &
                  default=0, debuggingParam=.true., do_not_log=.not.OBC%debug)
-    call get_param(param_file, mdl, "OBC_REVERSE_SEGMENT_ORDER", OBC%reverse_segment_order, &
+  call get_param(param_file, mdl, "OBC_REVERSE_SEGMENT_ORDER", OBC%reverse_segment_order, &
                  "If true, store the OBC segments internally and handle them in the reverse "//&
                  "order from that with which they are specified via external parameters to test "//&
                  "for dependencies on the order with which the OBC segments are applied.", &
                  default=.false., debuggingParam=.true., do_not_log=(OBC%number_of_segments<2))
 
-
-    call get_param(param_file, mdl, "OBC_SILLY_THICK", OBC%silly_h, &
+  call get_param(param_file, mdl, "OBC_SILLY_THICK", OBC%silly_h, &
                  "A silly value of thicknesses used outside of open boundary "//&
                  "conditions for debugging.", units="m", default=0.0, scale=US%m_to_Z, &
                  do_not_log=.not.debugging_tests, debuggingParam=.true.)
-    call get_param(param_file, mdl, "OBC_SILLY_VEL", OBC%silly_u, &
+  call get_param(param_file, mdl, "OBC_SILLY_VEL", OBC%silly_u, &
                  "A silly value of velocities used outside of open boundary "//&
                  "conditions for debugging.", units="m/s", default=0.0, scale=US%m_s_to_L_T, &
                  do_not_log=.not.debugging_tests, debuggingParam=.true.)
-    call get_param(param_file, mdl, "ENABLE_BUGS_BY_DEFAULT", enable_bugs, &
+  call get_param(param_file, mdl, "ENABLE_BUGS_BY_DEFAULT", enable_bugs, &
                  default=.true., do_not_log=.true.)  ! This is logged from MOM.F90.
-    call get_param(param_file, mdl, "EXTERIOR_OBC_BUG", OBC%exterior_OBC_bug, &
+  call get_param(param_file, mdl, "EXTERIOR_OBC_BUG", OBC%exterior_OBC_bug, &
                  "If true, recover a bug in barotropic solver and other routines when "//&
                  "boundary contitions interior to the domain are used.", &
                  default=enable_bugs)
-    call get_param(param_file, mdl, "OBC_HOR_INDEXING_BUG", OBC%hor_index_bug, &
+  call get_param(param_file, mdl, "OBC_HOR_INDEXING_BUG", OBC%hor_index_bug, &
                  "If true, recover set of a horizontal indexing bugs in the OBC code.", &
                  default=enable_bugs)
-    call get_param(param_file, mdl, "OBC_RESERVOIR_INIT_BUG", OBC%reservoir_init_bug, &
+  call get_param(param_file, mdl, "OBC_RESERVOIR_INIT_BUG", OBC%reservoir_init_bug, &
                  "If true, set the OBC tracer reservoirs at the startup of a new run from the "//&
                  "interior tracer concentrations regardless of properties that may be explicitly "//&
                  "specified for the reservoir concentrations.", default=enable_bugs, do_not_log=.true.)
-    reentrant_x = .false.
-    call get_param(param_file, mdl, "REENTRANT_X", reentrant_x, default=.true.)
-    reentrant_y = .false.
-    call get_param(param_file, mdl, "REENTRANT_Y", reentrant_y, default=.false.)
+  call get_param(param_file, mdl, "REENTRANT_X", reentrant_x, default=.true.)
+  call get_param(param_file, mdl, "REENTRANT_Y", reentrant_y, default=.false.)
 
-    ! Allocate everything
-    allocate(OBC%segment(1:OBC%number_of_segments))
-    do n=1,OBC%number_of_segments
-      OBC%segment(n)%Flather = .false.
-      OBC%segment(n)%radiation = .false.
-      OBC%segment(n)%radiation_tan = .false.
-      OBC%segment(n)%radiation_grad = .false.
-      OBC%segment(n)%oblique = .false.
-      OBC%segment(n)%oblique_tan = .false.
-      OBC%segment(n)%oblique_grad = .false.
-      OBC%segment(n)%nudged = .false.
-      OBC%segment(n)%nudged_tan = .false.
-      OBC%segment(n)%nudged_grad = .false.
-      OBC%segment(n)%specified = .false.
-      OBC%segment(n)%specified_tan = .false.
-      OBC%segment(n)%specified_grad = .false.
-      OBC%segment(n)%open = .false.
-      OBC%segment(n)%gradient = .false.
-      OBC%segment(n)%values_needed = .false.
-      OBC%segment(n)%u_values_needed = .false.
-      OBC%segment(n)%uamp_values_needed = OBC%add_tide_constituents
-      OBC%segment(n)%uphase_values_needed = OBC%add_tide_constituents
-      OBC%segment(n)%v_values_needed = .false.
-      OBC%segment(n)%vamp_values_needed = OBC%add_tide_constituents
-      OBC%segment(n)%vphase_values_needed = OBC%add_tide_constituents
-      OBC%segment(n)%t_values_needed = .false.
-      OBC%segment(n)%s_values_needed = .false.
-      OBC%segment(n)%z_values_needed = .false.
-      OBC%segment(n)%zamp_values_needed = OBC%add_tide_constituents
-      OBC%segment(n)%zphase_values_needed = OBC%add_tide_constituents
-      OBC%segment(n)%g_values_needed = .false.
-      OBC%segment(n)%direction = OBC_NONE
-      OBC%segment(n)%is_N_or_S = .false.
-      OBC%segment(n)%is_E_or_W = .false.
-      OBC%segment(n)%is_E_or_W_2 = .false.
-      OBC%segment(n)%Velocity_nudging_timescale_in = 0.0
-      OBC%segment(n)%Velocity_nudging_timescale_out = 0.0
-      OBC%segment(n)%num_fields = 0
-    enddo
-    allocate(OBC%segnum_u(G%IsdB:G%IedB,G%jsd:G%jed), source=0)
-    allocate(OBC%segnum_v(G%isd:G%ied,G%JsdB:G%JedB), source=0)
-    OBC%u_OBCs_on_PE = .false.
-    OBC%v_OBCs_on_PE = .false.
+  ! Allocate everything
+  allocate(OBC%segment(1:OBC%number_of_segments))
+  do n=1,OBC%number_of_segments
+    OBC%segment(n)%Flather = .false.
+    OBC%segment(n)%radiation = .false.
+    OBC%segment(n)%radiation_tan = .false.
+    OBC%segment(n)%radiation_grad = .false.
+    OBC%segment(n)%oblique = .false.
+    OBC%segment(n)%oblique_tan = .false.
+    OBC%segment(n)%oblique_grad = .false.
+    OBC%segment(n)%nudged = .false.
+    OBC%segment(n)%nudged_tan = .false.
+    OBC%segment(n)%nudged_grad = .false.
+    OBC%segment(n)%specified = .false.
+    OBC%segment(n)%specified_tan = .false.
+    OBC%segment(n)%specified_grad = .false.
+    OBC%segment(n)%open = .false.
+    OBC%segment(n)%gradient = .false.
+    OBC%segment(n)%values_needed = .false.
+    OBC%segment(n)%u_values_needed = .false.
+    OBC%segment(n)%uamp_values_needed = OBC%add_tide_constituents
+    OBC%segment(n)%uphase_values_needed = OBC%add_tide_constituents
+    OBC%segment(n)%v_values_needed = .false.
+    OBC%segment(n)%vamp_values_needed = OBC%add_tide_constituents
+    OBC%segment(n)%vphase_values_needed = OBC%add_tide_constituents
+    OBC%segment(n)%t_values_needed = .false.
+    OBC%segment(n)%s_values_needed = .false.
+    OBC%segment(n)%z_values_needed = .false.
+    OBC%segment(n)%zamp_values_needed = OBC%add_tide_constituents
+    OBC%segment(n)%zphase_values_needed = OBC%add_tide_constituents
+    OBC%segment(n)%g_values_needed = .false.
+    OBC%segment(n)%direction = OBC_NONE
+    OBC%segment(n)%is_N_or_S = .false.
+    OBC%segment(n)%is_E_or_W = .false.
+    OBC%segment(n)%is_E_or_W_2 = .false.
+    OBC%segment(n)%Velocity_nudging_timescale_in = 0.0
+    OBC%segment(n)%Velocity_nudging_timescale_out = 0.0
+    OBC%segment(n)%num_fields = 0
+  enddo
+  allocate(OBC%segnum_u(G%IsdB:G%IedB,G%jsd:G%jed), source=0)
+  allocate(OBC%segnum_v(G%isd:G%ied,G%JsdB:G%JedB), source=0)
+  OBC%u_OBCs_on_PE = .false.
+  OBC%v_OBCs_on_PE = .false.
 
-    do n=1,OBC%number_of_segments
-      n_seg = n ; if (OBC%reverse_segment_order) n_seg = OBC%number_of_segments + 1 - n
-      write(segment_param_str(1:15),"('OBC_SEGMENT_',i3.3)") n
-      call get_param(param_file, mdl, segment_param_str, segment_str, &
-           "Documentation needs to be dynamic?????", &
-           fail_if_missing=.true.)
-      segment_str = remove_spaces(segment_str)
-      if (segment_str(1:2) == 'I=') then
-        call setup_u_point_obc(OBC, G, US, segment_str, n_seg, n, param_file, reentrant_y)
-      elseif (segment_str(1:2) == 'J=') then
-        call setup_v_point_obc(OBC, G, US, segment_str, n_seg, n, param_file, reentrant_x)
-      else
-        call MOM_error(FATAL, "MOM_open_boundary.F90, open_boundary_config: "//&
-             "Unable to interpret "//segment_param_str//" = "//trim(segment_str))
-      endif
-    enddo
-    ! Set arrays indicating the segment number and segment direction, and also store the
-    ! range of indices within which various orientations of OBCs can be found on this PE.
-    call set_segnum_signs(OBC, G)
-
-    ! Moved this earlier because time_interp_external_init needs to be called
-    ! before anything that uses time_interp_external (such as initialize_segment_data)
-    if (OBC%specified_u_BCs_exist_globally .or. OBC%specified_v_BCs_exist_globally .or. &
-      OBC%open_u_BCs_exist_globally .or. OBC%open_v_BCs_exist_globally) then
-      ! Need this for ocean_only mode boundary interpolation.
-      call time_interp_external_init()
+  do n=1,OBC%number_of_segments
+    n_seg = n ; if (OBC%reverse_segment_order) n_seg = OBC%number_of_segments + 1 - n
+    write(segment_param_str(1:15),"('OBC_SEGMENT_',i3.3)") n
+    call get_param(param_file, mdl, segment_param_str, segment_str, &
+         "Documentation needs to be dynamic?????", &
+         fail_if_missing=.true.)
+    segment_str = remove_spaces(segment_str)
+    if (segment_str(1:2) == 'I=') then
+      call setup_u_point_obc(OBC, G, US, segment_str, n_seg, n, param_file, reentrant_y)
+    elseif (segment_str(1:2) == 'J=') then
+      call setup_v_point_obc(OBC, G, US, segment_str, n_seg, n, param_file, reentrant_x)
+    else
+      call MOM_error(FATAL, "MOM_open_boundary.F90, open_boundary_config: "//&
+           "Unable to interpret "//segment_param_str//" = "//trim(segment_str))
     endif
-    !    if (open_boundary_query(OBC, needs_ext_seg_data=.true.)) &
- !   call initialize_segment_data(G, OBC, param_file)
+  enddo
+  ! Set arrays indicating the segment number and segment direction, and also store the
+  ! range of indices within which various orientations of OBCs can be found on this PE.
+  call set_segnum_signs(OBC, G)
 
-    if (open_boundary_query(OBC, apply_open_OBC=.true.)) then
-      call get_param(param_file, mdl, "OBC_RADIATION_MAX", OBC%rx_max, &
+  ! Moved this earlier because time_interp_external_init needs to be called
+  ! before anything that uses time_interp_external (such as initialize_segment_data)
+  if (OBC%specified_u_BCs_exist_globally .or. OBC%specified_v_BCs_exist_globally .or. &
+    OBC%open_u_BCs_exist_globally .or. OBC%open_v_BCs_exist_globally) then
+    ! Need this for ocean_only mode boundary interpolation.
+    call time_interp_external_init()
+  endif
+  ! if (open_boundary_query(OBC, needs_ext_seg_data=.true.)) &
+  !   call initialize_segment_data(G, OBC, param_file)
+
+  if (open_boundary_query(OBC, apply_open_OBC=.true.)) then
+    call get_param(param_file, mdl, "OBC_RADIATION_MAX", OBC%rx_max, &
                    "The maximum magnitude of the baroclinic radiation velocity (or speed of "//&
                    "characteristics), in gridpoints per timestep.  This is only "//&
                    "used if one of the open boundary segments is using Orlanski.", &
                    units="nondim", default=1.0)
-      call get_param(param_file, mdl, "OBC_RAD_VEL_WT", OBC%gamma_uv, &
+    call get_param(param_file, mdl, "OBC_RAD_VEL_WT", OBC%gamma_uv, &
                    "The relative weighting for the baroclinic radiation "//&
                    "velocities (or speed of characteristics) at the new "//&
                    "time level (1) or the running mean (0) for velocities. "//&
                    "Valid values range from 0 to 1. This is only used if "//&
                    "one of the open boundary segments is using Orlanski.", &
                    units="nondim", default=0.3)
-    endif
+  endif
 
-    Lscale_in = 0.
-    Lscale_out = 0.
-    if (open_boundary_query(OBC, apply_open_OBC=.true.)) then
-      call get_param(param_file, mdl, "OBC_TRACER_RESERVOIR_LENGTH_SCALE_OUT ", Lscale_out, &
-                 "An effective length scale for restoring the tracer concentration "//&
-                 "at the boundaries to externally imposed values when the flow "//&
-                 "is exiting the domain.", units="m", default=0.0, scale=US%m_to_L)
-
-      call get_param(param_file, mdl, "OBC_TRACER_RESERVOIR_LENGTH_SCALE_IN ", Lscale_in, &
-                 "An effective length scale for restoring the tracer concentration "//&
-                 "at the boundaries to values from the interior when the flow "//&
-                 "is entering the domain.", units="m", default=0.0, scale=US%m_to_L)
-    endif
+  Lscale_in = 0.
+  Lscale_out = 0.
+  if (open_boundary_query(OBC, apply_open_OBC=.true.)) then
+    call get_param(param_file, mdl, "OBC_TRACER_RESERVOIR_LENGTH_SCALE_OUT ", Lscale_out, &
+                   "An effective length scale for restoring the tracer concentration "//&
+                   "at the boundaries to externally imposed values when the flow "//&
+                   "is exiting the domain.", units="m", default=0.0, scale=US%m_to_L)
+
+    call get_param(param_file, mdl, "OBC_TRACER_RESERVOIR_LENGTH_SCALE_IN ", Lscale_in, &
+                   "An effective length scale for restoring the tracer concentration "//&
+                   "at the boundaries to values from the interior when the flow "//&
+                   "is entering the domain.", units="m", default=0.0, scale=US%m_to_L)
+  endif
 
-    if (mask_outside) call mask_outside_OBCs(G, US, param_file, OBC)
+  if (mask_outside) call mask_outside_OBCs(G, US, param_file, OBC)
 
-    ! All tracers are using the same restoring length scale for now, but we may want to make this
-    ! tracer-specific in the future for example, in cases where certain tracers are poorly constrained
-    ! by data while others are well constrained - MJH.
-    do n=1,OBC%number_of_segments
-      OBC%segment(n)%Tr_InvLscale_in = 0.0
-      if (Lscale_in>0.) OBC%segment(n)%Tr_InvLscale_in =  1.0/Lscale_in
-      OBC%segment(n)%Tr_InvLscale_out = 0.0
-      if (Lscale_out>0.) OBC%segment(n)%Tr_InvLscale_out =  1.0/Lscale_out
-    enddo
+  ! All tracers are using the same restoring length scale for now, but we may want to make this
+  ! tracer-specific in the future for example, in cases where certain tracers are poorly constrained
+  ! by data while others are well constrained - MJH.
+  do n=1,OBC%number_of_segments
+    OBC%segment(n)%Tr_InvLscale_in = 0.0
+    if (Lscale_in>0.) OBC%segment(n)%Tr_InvLscale_in =  1.0/Lscale_in
+    OBC%segment(n)%Tr_InvLscale_out = 0.0
+    if (Lscale_out>0.) OBC%segment(n)%Tr_InvLscale_out =  1.0/Lscale_out
+  enddo
 
-    Lscale_in = 0.
-    Lscale_out = 0.
-    if (open_boundary_query(OBC, apply_open_OBC=.true.)) then
-      call get_param(param_file, mdl, "OBC_THICKNESS_RESERVOIR_LENGTH_SCALE_OUT ", Lscale_out, &
-                 "An effective length scale for restoring the layer thickness "//&
-                 "at the boundaries to externally imposed values when the flow "//&
-                 "is exiting the domain.", units="m", default=0.0, scale=US%m_to_L)
-
-      call get_param(param_file, mdl, "OBC_THICKNESS_RESERVOIR_LENGTH_SCALE_IN ", Lscale_in, &
-                 "An effective length scale for restoring the layer thickness "//&
-                 "at the boundaries to values from the interior when the flow "//&
-                 "is entering the domain.", units="m", default=0.0, scale=US%m_to_L)
-    endif
+  Lscale_in = 0.
+  Lscale_out = 0.
+  if (open_boundary_query(OBC, apply_open_OBC=.true.)) then
+    call get_param(param_file, mdl, "OBC_THICKNESS_RESERVOIR_LENGTH_SCALE_OUT ", Lscale_out, &
+                   "An effective length scale for restoring the layer thickness "//&
+                   "at the boundaries to externally imposed values when the flow "//&
+                   "is exiting the domain.", units="m", default=0.0, scale=US%m_to_L)
+
+    call get_param(param_file, mdl, "OBC_THICKNESS_RESERVOIR_LENGTH_SCALE_IN ", Lscale_in, &
+                   "An effective length scale for restoring the layer thickness "//&
+                   "at the boundaries to values from the interior when the flow "//&
+                   "is entering the domain.", units="m", default=0.0, scale=US%m_to_L)
+  endif
 
-    do n=1,OBC%number_of_segments
-      OBC%segment(n)%Th_InvLscale_in = 0.0
-      if (Lscale_in>0.) OBC%segment(n)%Th_InvLscale_in =  1.0/Lscale_in
-      OBC%segment(n)%Th_InvLscale_out = 0.0
-      if (Lscale_out>0.) OBC%segment(n)%Th_InvLscale_out =  1.0/Lscale_out
-      if (Lscale_in>0. .or. Lscale_out>0.) then
-        if (OBC%segment(n)%is_E_or_W_2) then
-          OBC%thickness_x_reservoirs_used = .true.
-          OBC%use_h_res = .true.
-        else
-          OBC%thickness_y_reservoirs_used = .true.
-          OBC%use_h_res = .true.
-        endif
+  do n=1,OBC%number_of_segments
+    OBC%segment(n)%Th_InvLscale_in = 0.0
+    if (Lscale_in>0.) OBC%segment(n)%Th_InvLscale_in =  1.0/Lscale_in
+    OBC%segment(n)%Th_InvLscale_out = 0.0
+    if (Lscale_out>0.) OBC%segment(n)%Th_InvLscale_out =  1.0/Lscale_out
+    if (Lscale_in>0. .or. Lscale_out>0.) then
+      if (OBC%segment(n)%is_E_or_W_2) then
+        OBC%thickness_x_reservoirs_used = .true.
+        OBC%use_h_res = .true.
+      else
+        OBC%thickness_y_reservoirs_used = .true.
+        OBC%use_h_res = .true.
       endif
-    enddo
+    endif
+  enddo
 
-    call get_param(param_file, mdl, "REMAPPING_SCHEME", OBC%remappingScheme, &
-          default=remappingDefaultScheme, do_not_log=.true.)
-    call get_param(param_file, mdl, "OBC_REMAPPING_SCHEME", OBC%remappingScheme, &
-          "This sets the reconstruction scheme used "//&
-          "for OBC vertical remapping for all variables. "//&
-          "It can be one of the following schemes: \n"//&
-          trim(remappingSchemesDoc), default=OBC%remappingScheme)
-    call get_param(param_file, mdl, "FATAL_CHECK_RECONSTRUCTIONS", OBC%check_reconstruction, &
-          "If true, cell-by-cell reconstructions are checked for "//&
-          "consistency and if non-monotonicity or an inconsistency is "//&
-          "detected then a FATAL error is issued.", default=.false., do_not_log=.true.)
-    call get_param(param_file, mdl, "FATAL_CHECK_REMAPPING", OBC%check_remapping, &
-          "If true, the results of remapping are checked for "//&
-          "conservation and new extrema and if an inconsistency is "//&
-          "detected then a FATAL error is issued.", default=.false., do_not_log=.true.)
-    call get_param(param_file, mdl, "BRUSHCUTTER_MODE", OBC%brushcutter_mode, &
-         "If true, read external OBC data on the supergrid.", &
-         default=.false.)
-    call get_param(param_file, mdl, "REMAP_BOUND_INTERMEDIATE_VALUES", OBC%force_bounds_in_subcell, &
-          "If true, the values on the intermediate grid used for remapping "//&
-          "are forced to be bounded, which might not be the case due to "//&
-          "round off.", default=.false., do_not_log=.true.)
-    call get_param(param_file, mdl, "DEFAULT_ANSWER_DATE", default_answer_date, &
+  call get_param(param_file, mdl, "REMAPPING_SCHEME", OBC%remappingScheme, &
+       default=remappingDefaultScheme, do_not_log=.true.)
+  call get_param(param_file, mdl, "OBC_REMAPPING_SCHEME", OBC%remappingScheme, &
+       "This sets the reconstruction scheme used "//&
+       "for OBC vertical remapping for all variables. "//&
+       "It can be one of the following schemes: \n"//&
+       trim(remappingSchemesDoc), default=OBC%remappingScheme)
+  call get_param(param_file, mdl, "FATAL_CHECK_RECONSTRUCTIONS", OBC%check_reconstruction, &
+       "If true, cell-by-cell reconstructions are checked for "//&
+       "consistency and if non-monotonicity or an inconsistency is "//&
+       "detected then a FATAL error is issued.", default=.false., do_not_log=.true.)
+  call get_param(param_file, mdl, "FATAL_CHECK_REMAPPING", OBC%check_remapping, &
+       "If true, the results of remapping are checked for "//&
+       "conservation and new extrema and if an inconsistency is "//&
+       "detected then a FATAL error is issued.", default=.false., do_not_log=.true.)
+  call get_param(param_file, mdl, "BRUSHCUTTER_MODE", OBC%brushcutter_mode, &
+       "If true, read external OBC data on the supergrid.", &
+       default=.false.)
+  call get_param(param_file, mdl, "REMAP_BOUND_INTERMEDIATE_VALUES", OBC%force_bounds_in_subcell, &
+       "If true, the values on the intermediate grid used for remapping "//&
+       "are forced to be bounded, which might not be the case due to "//&
+       "round off.", default=.false., do_not_log=.true.)
+  call get_param(param_file, mdl, "DEFAULT_ANSWER_DATE", default_answer_date, &
                  "This sets the default value for the various _ANSWER_DATE parameters.", &
                  default=99991231)
-    call get_param(param_file, mdl, "REMAPPING_ANSWER_DATE", OBC%remap_answer_date, &
+  call get_param(param_file, mdl, "REMAPPING_ANSWER_DATE", OBC%remap_answer_date, &
                  "The vintage of the expressions and order of arithmetic to use for remapping.  "//&
                  "Values below 20190101 result in the use of older, less accurate expressions "//&
                  "that were in use at the end of 2018.  Higher values result in the use of more "//&
                  "robust and accurate forms of mathematically equivalent expressions.", &
                  default=default_answer_date)
-    call get_param(param_file, mdl, "REMAPPING_USE_OM4_SUBCELLS", OBC%om4_remap_via_sub_cells, &
-                   do_not_log=.true., default=.true.)
+  call get_param(param_file, mdl, "REMAPPING_USE_OM4_SUBCELLS", OBC%om4_remap_via_sub_cells, &
+                 do_not_log=.true., default=.true.)
 
-    call get_param(param_file, mdl, "OBC_REMAPPING_USE_OM4_SUBCELLS", OBC%om4_remap_via_sub_cells, &
+  call get_param(param_file, mdl, "OBC_REMAPPING_USE_OM4_SUBCELLS", OBC%om4_remap_via_sub_cells, &
                  "If true, use the OM4 remapping-via-subcells algorithm for neutral diffusion. "//&
                  "See REMAPPING_USE_OM4_SUBCELLS for more details. "//&
                  "We recommend setting this option to false.", default=OBC%om4_remap_via_sub_cells)
 
-  endif ! OBC%number_of_segments > 0
-
-    ! Safety check
+  ! Safety check
   if ((OBC%open_u_BCs_exist_globally .or. OBC%open_v_BCs_exist_globally) .and. &
        .not.G%symmetric ) call MOM_error(FATAL, &
        "MOM_open_boundary, open_boundary_config: "//&
@@ -2264,9 +2252,9 @@ subroutine open_boundary_impose_land_mask(OBC, G, areaCu, areaCv, US)
       enddo
       do J=segment%HI%JsdB+1,segment%HI%JedB-1
         if (segment%direction == OBC_DIRECTION_W) then
-          G%mask2dCv(i,J) = 0 ; G%OBCmaskCv(i,J) = 0.0
+          G%mask2dCv(i,J) = 0 ; G%OBCmaskCv(i,J) = 0.0 ; G%IdyCv_OBCmask(i,J) = 0.0
         else
-          G%mask2dCv(i+1,J) = 0.0 ; G%OBCmaskCv(i+1,J) = 0.0
+          G%mask2dCv(i+1,J) = 0.0 ; G%OBCmaskCv(i+1,J) = 0.0 ; G%IdyCv_OBCmask(i+1,J) = 0.0
         endif
       enddo
     else
@@ -2282,9 +2270,9 @@ subroutine open_boundary_impose_land_mask(OBC, G, areaCu, areaCv, US)
       enddo
       do I=segment%HI%IsdB+1,segment%HI%IedB-1
         if (segment%direction == OBC_DIRECTION_S) then
-          G%mask2dCu(I,j) = 0.0 ; G%OBCmaskCu(I,j) = 0.0
+          G%mask2dCu(I,j) = 0.0 ; G%OBCmaskCu(I,j) = 0.0 ; G%IdxCu_OBCmask(I,j) = 0.0
         else
-          G%mask2dCu(I,j+1) = 0.0 ; G%OBCmaskCu(I,j+1) = 0.0
+          G%mask2dCu(I,j+1) = 0.0 ; G%OBCmaskCu(I,j+1) = 0.0 ; G%IdxCu_OBCmask(I,j+1) = 0.0
         endif
       enddo
     endif
@@ -2298,12 +2286,12 @@ subroutine open_boundary_impose_land_mask(OBC, G, areaCu, areaCv, US)
     if (segment%is_E_or_W) then
       I=segment%HI%IsdB
       do j=segment%HI%jsd,segment%HI%jed
-        G%OBCmaskCu(I,j) = 0.0
+        G%OBCmaskCu(I,j) = 0.0 ; G%IdxCu_OBCmask(I,j) = 0.0
       enddo
     else
       J=segment%HI%JsdB
       do i=segment%HI%isd,segment%HI%ied
-        G%OBCmaskCv(i,J) = 0.0
+        G%OBCmaskCv(i,J) = 0.0 ; G%IdyCv_OBCmask(i,J) = 0.0
       enddo
     endif
   enddo
@@ -2501,7 +2489,7 @@ subroutine set_initialized_OBC_tracer_reservoirs(G, OBC, restart_CS)
   type(ocean_OBC_type),           intent(in)    :: OBC !< Open boundary control structure
   type(MOM_restart_CS),           intent(inout) :: restart_CS !< MOM restart control structure
   character(len=12) :: x_var_name, y_var_name
-  integer :: i, j, k, m, n
+  integer :: m
 
   do m=1,OBC%ntr
     ! Set the names of the reservoirs for this tracer in the restart file
@@ -2576,7 +2564,7 @@ subroutine radiation_open_bdry_conds(OBC, u_new, u_old, v_new, v_old, G, GV, US,
   type(verticalGrid_type),                    intent(in)    :: GV    !< The ocean's vertical grid structure
   type(ocean_OBC_type),                       pointer       :: OBC   !< Open boundary control structure
   real, dimension(SZIB_(G),SZJ_(G),SZK_(GV)), intent(inout) :: u_new !< On exit, new u values on open boundaries
-                                                                     !! On entry, the old time-level v but including
+                                                                     !! On entry, the old time-level u but including
                                                                      !! barotropic accelerations [L T-1 ~> m s-1].
   real, dimension(SZIB_(G),SZJ_(G),SZK_(GV)), intent(in)    :: u_old !< Original unadjusted u [L T-1 ~> m s-1]
   real, dimension(SZI_(G),SZJB_(G),SZK_(GV)), intent(inout) :: v_new !< On exit, new v values on open boundaries.
@@ -4946,8 +4934,6 @@ subroutine segment_thickness_reservoir_init(GV, US, OBC, param_file)
                   ! salinity, or other various units depending on what rescaling has occurred previously.
   integer :: nseg, m, isd, ied, jsd, jed, IsdB, IedB, JsdB, JedB
   integer :: fd_id
-  character(len=256) :: mesg    ! Message for error messages.
-  character(len=32) :: name
   type(OBC_segment_type), pointer :: segment => NULL() ! pointer to segment type list
   integer, save :: init_calls = 0
 
@@ -5205,8 +5191,8 @@ subroutine register_obgc_segments(GV, OBC, tr_Reg, param_file, tr_name)
   type(param_file_type),      intent(in)    :: param_file !< file to parse for  model parameter values
   character(len=*),           intent(in)    :: tr_name    !< Tracer name
 ! Local variables
-  integer :: isd, ied, IsdB, IedB, jsd, jed, JsdB, JedB, nz, nf, ntr_id, fd_id
-  integer :: i, j, k, n, m
+  integer :: ntr_id, fd_id
+  integer :: n, m
   type(OBC_segment_type), pointer :: segment => NULL() ! pointer to segment type list
   type(tracer_type), pointer      :: tr_ptr => NULL()
 
@@ -5431,7 +5417,6 @@ subroutine mask_outside_OBCs(G, US, param_file, OBC)
 
   ! Local variables
   integer :: i, j
-  integer :: l_seg
   logical :: fatal_error = .False.
   real    :: min_depth  ! The minimum depth for ocean points [Z ~> m]
   real    :: mask_depth ! The masking depth for ocean points [Z ~> m]
@@ -5951,7 +5936,7 @@ subroutine update_segment_thickness_reservoirs(G, GV, uhr, vhr, h, OBC)
   real :: fac1            ! The denominator of the expression for tracer updates [nondim]
   real :: I_scale         ! The inverse of the scaling factor for the tracers.
                           ! For salinity the units would be [ppt S-1 ~> 1]
-  integer :: i, j, k, m, n, nz, fd_id
+  integer :: i, j, k, n, nz, fd_id
   integer :: ishift, idir, jshift, jdir
   real :: resrv_lfac_out  ! The reservoir inverse length scale scaling factor for the outward
                           ! direction per field [nondim]
@@ -7032,7 +7017,6 @@ subroutine chksum_OBC_segment_data(segment, GV, US, nk, nseg_out)
   real :: norm ! A sign change used when rotating a normal component [nondim]
   real :: tang ! A sign change used when rotating a tangential component [nondim]
   character(len=8) :: sn, segno
-  character(len=1024) :: mesg
   integer :: dir        ! This indicates the internal logical orientation of a segment
 
     dir = segment%direction
diff --git a/src/core/MOM_transcribe_grid.F90 b/src/core/MOM_transcribe_grid.F90
index d9ca19985f..5fd28164a2 100644
--- a/src/core/MOM_transcribe_grid.F90
+++ b/src/core/MOM_transcribe_grid.F90
@@ -56,6 +56,7 @@ subroutine copy_dyngrid_to_MOM_grid(dG, oG, US)
     oG%dyT(i,j) = dG%dyT(i+ido,j+jdo)
     oG%areaT(i,j) = dG%areaT(i+ido,j+jdo)
     oG%bathyT(i,j) = dG%bathyT(i+ido,j+jdo) - oG%Z_ref
+    oG%meanSL(i,j) = dG%meanSL(i+ido,j+jdo) + oG%Z_ref
 
     oG%dF_dx(i,j) = dG%dF_dx(i+ido,j+jdo)
     oG%dF_dy(i,j) = dG%dF_dy(i+ido,j+jdo)
@@ -145,6 +146,7 @@ subroutine copy_dyngrid_to_MOM_grid(dG, oG, US)
 ! Update the halos in case the dynamic grid has smaller halos than the ocean grid.
   call pass_var(oG%areaT, oG%Domain)
   call pass_var(oG%bathyT, oG%Domain)
+  call pass_var(oG%meanSL, oG%Domain)
   call pass_var(oG%geoLonT, oG%Domain)
   call pass_var(oG%geoLatT, oG%Domain)
   call pass_vector(oG%dxT, oG%dyT, oG%Domain, To_All+Scalar_Pair, AGRID)
@@ -217,6 +219,7 @@ subroutine copy_MOM_grid_to_dyngrid(oG, dG, US)
     dG%dyT(i,j) = oG%dyT(i+ido,j+jdo)
     dG%areaT(i,j) = oG%areaT(i+ido,j+jdo)
     dG%bathyT(i,j) = oG%bathyT(i+ido,j+jdo) + oG%Z_ref
+    dG%meanSL(i,j) = oG%meanSL(i+ido,j+jdo) - oG%Z_ref
 
     dG%dF_dx(i,j) = oG%dF_dx(i+ido,j+jdo)
     dG%dF_dy(i,j) = oG%dF_dy(i+ido,j+jdo)
@@ -307,6 +310,7 @@ subroutine copy_MOM_grid_to_dyngrid(oG, dG, US)
 ! Update the halos in case the dynamic grid has smaller halos than the ocean grid.
   call pass_var(dG%areaT, dG%Domain)
   call pass_var(dG%bathyT, dG%Domain)
+  call pass_var(dG%meanSL, dG%Domain)
   call pass_var(dG%geoLonT, dG%Domain)
   call pass_var(dG%geoLatT, dG%Domain)
   call pass_vector(dG%dxT, dG%dyT, dG%Domain, To_All+Scalar_Pair, AGRID)
diff --git a/src/core/MOM_variables.F90 b/src/core/MOM_variables.F90
index c6483f8cef..5061010d6a 100644
--- a/src/core/MOM_variables.F90
+++ b/src/core/MOM_variables.F90
@@ -89,9 +89,9 @@ module MOM_variables
                          !! When conservative temperature is used, this is
                          !! constant and exactly 3991.86795711963 J degC-1 kg-1.
   logical :: T_is_conT = .false. !< If true, the temperature variable tv%T is
-                         !! actually the conservative temperature [degC].
+                         !! actually the conservative temperature [C ~> degC].
   logical :: S_is_absS = .false. !< If true, the salinity variable tv%S is
-                         !! actually the absolute salinity in units of [gSalt kg-1].
+                         !! actually the absolute salinity in units of [S ~> gSalt kg-1].
   real :: min_salinity   !< The minimum value of salinity when BOUND_SALINITY=True [S ~> ppt].
   real, allocatable, dimension(:,:,:) :: SpV_avg
                          !< The layer averaged in situ specific volume [R-1 ~> m3 kg-1].
diff --git a/src/core/MOM_verticalGrid.F90 b/src/core/MOM_verticalGrid.F90
index 4713fb6797..13207121e7 100644
--- a/src/core/MOM_verticalGrid.F90
+++ b/src/core/MOM_verticalGrid.F90
@@ -74,7 +74,7 @@ module MOM_verticalGrid
   real :: H_to_m        !< A constant that translates distances in the units of thickness
                         !! to m [m H-1 ~> 1 or m3 kg-1].
   real :: H_to_Pa       !< A constant that translates the units of thickness to pressure
-                        !! [Pa H-1 = kg m-1 s-2 H-1 ~> kg m-2 s-2 or m s-2].
+                        !! [Pa H-1 ~> kg m-2 s-2 or m s-2].
   real :: H_to_Z        !< A constant that translates thickness units to the units of
                         !! depth [Z H-1 ~> 1 or m3 kg-1].
   real :: Z_to_H        !< A constant that translates depth units to thickness units
diff --git a/src/diagnostics/MOM_diagnose_KdWork.F90 b/src/diagnostics/MOM_diagnose_KdWork.F90
index 8b89933169..06e7be36ae 100644
--- a/src/diagnostics/MOM_diagnose_KdWork.F90
+++ b/src/diagnostics/MOM_diagnose_KdWork.F90
@@ -32,13 +32,13 @@ module MOM_diagnose_kdwork
   ! 3d varying Kd contributions
   real, pointer, dimension(:,:,:) :: &
     Bflx_salt => NULL(), & !< Salinity contribution to buoyancy flux at interfaces
-                           !! [H Z T-3 ~> m2 s-3 or kg m-1 s-3 = W m-3]
+                           !! [H Z T-3 ~> m2 s-3 or W m-3]
     Bflx_temp => NULL(), & !< Temperature contribution to buoyancy flux at interfaces
-                           !! [H Z T-3 ~> m2 s-3 or kg m-1 s-3 = W m-3]
+                           !! [H Z T-3 ~> m2 s-3 or W m-3]
     Bflx_salt_dz => NULL(), & !< Salinity contribution to integral of buoyancy flux over layer
-                              !! [H Z2 T-3 ~> m3 s-3 or kg m-1 s-3 = W m-2]
+                              !! [H Z2 T-3 ~> m3 s-3 or W m-2]
     Bflx_temp_dz => NULL(), & !< Temperature contribution to integral of buoyancy flux over layer
-                              !! [H Z2 T-3 ~> m3 s-3 or kg m-1 s-3 = W m-2]
+                              !! [H Z2 T-3 ~> m3 s-3 or W m-2]
     ! The following are all allocatable arrays that store copies of process driven Kd, so that
     ! the process driven buoyancy flux and work can be derived at the end of the time step.
     Kd_salt => NULL(), &   !< total diapycnal diffusivity of salt at interfaces [H Z T-1 ~> m2 s-1 or kg m-1 s-1]
@@ -740,11 +740,11 @@ subroutine diagnoseKdWork(G, GV, N2, Kd, Bdif_flx, dz, Bdif_flx_dz)
   real, dimension(SZI_(G),SZJ_(G),SZK_(GV)+1), &
                            intent(in)  :: Kd   !< Diffusivity [H Z T-1 ~> m2 s-1 or kg m-1 s-1]
   real, dimension(SZI_(G),SZJ_(G),SZK_(GV)+1), &
-                           intent(out) :: Bdif_flx !< Buoyancy flux [H Z T-3 ~> m2 s-3 or kg m-1 s-3 = W m-3]
+                           intent(out) :: Bdif_flx !< Buoyancy flux [H Z T-3 ~> m2 s-3 or W m-3]
   real, dimension(SZI_(G),SZJ_(G),SZK_(GV)), &
                  intent(in), optional :: dz    !< Grid spacing [Z ~> m]
   real, dimension(SZI_(G),SZJ_(G),SZK_(GV)), &
-                intent(out), optional :: Bdif_flx_dz !< Buoyancy flux over layer [H Z2 T-3 ~> m3 s-3 or kg s-3 = W m-2]
+                intent(out), optional :: Bdif_flx_dz !< Buoyancy flux over layer [H Z2 T-3 ~> m3 s-3 or W m-2]
 
   integer :: i, j, k
 
diff --git a/src/diagnostics/MOM_diagnostics.F90 b/src/diagnostics/MOM_diagnostics.F90
index 6c220c79cf..b6ac8b772a 100644
--- a/src/diagnostics/MOM_diagnostics.F90
+++ b/src/diagnostics/MOM_diagnostics.F90
@@ -20,7 +20,9 @@ module MOM_diagnostics
 use MOM_domains,           only : create_group_pass, do_group_pass, group_pass_type
 use MOM_domains,           only : To_North, To_East
 use MOM_EOS,               only : calculate_density, calculate_density_derivs, EOS_domain
-use MOM_EOS,               only : cons_temp_to_pot_temp, abs_saln_to_prac_saln
+use MOM_EOS,               only : calculate_spec_vol
+use MOM_EOS,               only : cons_temp_to_pot_temp, pot_temp_to_cons_temp
+use MOM_EOS,               only : prac_saln_to_abs_saln, abs_saln_to_prac_saln
 use MOM_error_handler,     only : MOM_error, FATAL, WARNING
 use MOM_file_parser,       only : get_param, log_version, param_file_type
 use MOM_grid,              only : ocean_grid_type
@@ -97,6 +99,9 @@ module MOM_diagnostics
   integer :: id_cg_ebt         = -1, id_Rd_ebt         = -1
   integer :: id_p_ebt          = -1
   integer :: id_temp_int       = -1, id_salt_int       = -1
+  integer :: id_absscint       = -1, id_pfscint        = -1
+  integer :: id_scint          = -1
+  integer :: id_chcint         = -1, id_phcint         = -1
   integer :: id_mass_wt        = -1, id_col_mass       = -1
   integer :: id_masscello      = -1, id_masso          = -1
   integer :: id_volcello       = -1
@@ -409,7 +414,7 @@ subroutine calculate_diagnostic_fields(u, v, h, uh, vh, tv, ADp, CDp, p_surf, &
         call cons_temp_to_pot_temp(tv%T(:,j,k), tv%S(:,j,k), work_3d(:,j,k), tv%eqn_of_state, EOSdom)
       enddo ; enddo
       if (CS%id_Tpot > 0) call post_data(CS%id_Tpot, work_3d, CS%diag)
-      if (CS%id_tob > 0) call post_data(CS%id_tob, work_3d(:,:,nz), CS%diag, mask=G%mask2dT)
+      if (CS%id_tob > 0) call post_data(CS%id_tob, work_3d(:,:,nz), CS%diag)
       ! volume mean potential temperature
       if (CS%id_thetaoga>0) then
         thetaoga = global_volume_mean(work_3d, h, G, GV, tmp_scale=US%C_to_degC)
@@ -449,7 +454,7 @@ subroutine calculate_diagnostic_fields(u, v, h, uh, vh, tv, ADp, CDp, p_surf, &
     endif
   else
     ! Internal T&S variables are potential temperature & practical salinity
-    if (CS%id_tob > 0) call post_data(CS%id_tob, tv%T(:,:,nz), CS%diag, mask=G%mask2dT)
+    if (CS%id_tob > 0) call post_data(CS%id_tob, tv%T(:,:,nz), CS%diag)
     if (CS%id_tosq > 0) then
       do k=1,nz ; do j=js,je ; do i=is,ie
         work_3d(i,j,k) = tv%T(i,j,k)*tv%T(i,j,k)
@@ -485,7 +490,7 @@ subroutine calculate_diagnostic_fields(u, v, h, uh, vh, tv, ADp, CDp, p_surf, &
         call abs_saln_to_prac_saln(tv%S(:,j,k), work_3d(:,j,k), tv%eqn_of_state, EOSdom)
       enddo ; enddo
       if (CS%id_Sprac > 0) call post_data(CS%id_Sprac, work_3d, CS%diag)
-      if (CS%id_sob > 0) call post_data(CS%id_sob, work_3d(:,:,nz), CS%diag, mask=G%mask2dT)
+      if (CS%id_sob > 0) call post_data(CS%id_sob, work_3d(:,:,nz), CS%diag)
       ! volume mean salinity
       if (CS%id_soga>0) then
         soga = global_volume_mean(work_3d, h, G, GV, tmp_scale=US%S_to_ppt)
@@ -525,7 +530,7 @@ subroutine calculate_diagnostic_fields(u, v, h, uh, vh, tv, ADp, CDp, p_surf, &
     endif
   else
     ! Internal T&S variables are potential temperature & practical salinity
-    if (CS%id_sob > 0) call post_data(CS%id_sob, tv%S(:,:,nz), CS%diag, mask=G%mask2dT)
+    if (CS%id_sob > 0) call post_data(CS%id_sob, tv%S(:,:,nz), CS%diag)
     if (CS%id_sosq > 0) then
       do k=1,nz ; do j=js,je ; do i=is,ie
         work_3d(i,j,k) = tv%S(i,j,k)*tv%S(i,j,k)
@@ -904,9 +909,10 @@ subroutine calculate_vertical_integrals(h, tv, p_surf, G, GV, US, CS)
               ! at the ocean surface [R L2 T-2 ~> Pa].
     tr_int    ! vertical integral of a tracer times density,
               ! (Rho_0 in a Boussinesq model) [Conc R Z ~> Conc kg m-2].
-  real    :: IG_Earth  ! Inverse of gravitational acceleration [T2 Z L-2 ~> s2 m-1].
+  real :: tmp(SZI_(G),SZJ_(G),SZK_(GV)) ! Temporary array [defined at each usage]
 
   integer :: i, j, k, is, ie, js, je, nz
+  integer, dimension(2) :: EOSdom ! The i-computational domain for the equation of state
   is = G%isc ; ie = G%iec ; js = G%jsc ; je = G%jec ; nz = GV%ke
 
   if (CS%id_mass_wt > 0) then
@@ -951,6 +957,84 @@ subroutine calculate_vertical_integrals(h, tv, p_surf, G, GV, US, CS)
     if (CS%id_col_mass > 0) call post_data(CS%id_col_mass, mass, CS%diag)
   endif
 
+  ! Practical salinity expressed as salt mass content
+  if (CS%id_scint > 0) then
+    EOSdom(:) = EOS_domain(G%HI)
+    if (tv%S_is_absS) then
+      do k=1,nz ; do j=js,je
+        call abs_saln_to_prac_saln(tv%S(:,j,k), tmp(:,j,k), tv%eqn_of_state, EOSdom) ! "tmp" [S ~> psu]
+        do i=is,ie
+          tmp(i,j,k) = ( GV%H_to_RZ * h(i,j,k) ) * tmp(i,j,k) ! "tmp" [R Z S ~> kg m-2]
+        enddo
+      enddo ; enddo
+    else
+      do k=1,nz ; do j=js,je ; do i=is,ie
+        tmp(i,j,k) = ( GV%H_to_RZ * h(i,j,k) ) * tv%S(i,j,k) ! "tmp" [R Z S ~> kg m-2]
+      enddo ; enddo ; enddo
+    endif
+    call post_data(CS%id_scint, tmp, CS%diag)
+  endif
+  ! Absolute salinities expressed as salt mass content
+  if (CS%id_absscint > 0 .or. CS%id_pfscint > 0) then
+    EOSdom(:) = EOS_domain(G%HI)
+    if (tv%S_is_absS) then
+      do k=1,nz ; do j=js,je ; do i=is,ie
+        tmp(i,j,k) = ( GV%H_to_RZ * h(i,j,k) ) * tv%S(i,j,k) ! "tmp" [R Z S ~> kg m-2]
+      enddo ; enddo ; enddo
+    else
+      do k=1,nz ; do j=js,je
+        call prac_saln_to_abs_saln(tv%S(:,j,k), tmp(:,j,k), tv%eqn_of_state, EOSdom) ! "tmp" [S ~> ppt]
+        do i=is,ie
+          tmp(i,j,k) = ( GV%H_to_RZ * h(i,j,k) ) * tmp(i,j,k) ! [R Z S ~> kg m-2]
+        enddo
+      enddo ; enddo
+    endif
+    if (CS%id_absscint > 0) call post_data(CS%id_absscint, tmp, CS%diag)
+    ! Based on the definitions in https://www.teos-10.org/pubs/gsw/pdf/TEOS-10_Manual.pdf
+    ! The preformed salinity, S*, is the conserved salinity used in models (page 8).
+    ! Although we appear to be labeling tv%S absolute salinity, we do not use the function
+    ! that calculates the "absolute salinity anomaly ratio" which accounts for the
+    ! geographic variations in the types of dissolved salts.
+    ! Hence, I think there is no difference between preformed and absolute salinity
+    ! for the current implementation of TEOS-10 and so we post the same data for
+    ! absscint and pfscint.  -AJA
+    if (CS%id_pfscint > 0) call post_data(CS%id_pfscint, tmp, CS%diag)
+  endif
+  ! Potential temperature expressed as heat content
+  if (CS%id_phcint > 0) then
+    EOSdom(:) = EOS_domain(G%HI)
+    if (tv%T_is_conT) then
+      do k=1,nz ; do j=js,je
+        call cons_temp_to_pot_temp(tv%T(:,j,k), tv%S(:,j,k), tmp(:,j,k), tv%eqn_of_state, EOSdom) ! "tmp" [C ~> degC]
+        do i=is,ie
+          tmp(i,j,k) = ( ( tv%C_p * GV%H_to_RZ ) * h(i,j,k) ) * tmp(i,j,k) ! "tmp" [ Q R Z ~> J m-2]
+        enddo
+      enddo ; enddo
+    else
+      do k=1,nz ; do j=js,je ; do i=is,ie
+        tmp(i,j,k) = ( ( tv%C_p * GV%H_to_RZ ) * h(i,j,k) ) * tv%T(i,j,k) ! "tmp" [Q R Z ~> J m-2]
+      enddo ; enddo ; enddo
+    endif
+    call post_data(CS%id_phcint, tmp, CS%diag)
+  endif
+  ! Conservative temperature expressed as heat content
+  if (CS%id_chcint > 0) then
+    EOSdom(:) = EOS_domain(G%HI)
+    if (tv%T_is_conT) then
+      do k=1,nz ; do j=js,je ; do i=is,ie
+        tmp(i,j,k) = ( ( tv%C_p * GV%H_to_RZ ) * h(i,j,k) ) * tv%T(i,j,k) ! "tmp" [Q R Z ~> J m-2]
+      enddo ; enddo ; enddo
+    else
+      do k=1,nz ; do j=js,je
+        call pot_temp_to_cons_temp(tv%T(:,j,k), tv%S(:,j,k), tmp(:,j,k), tv%eqn_of_state, EOSdom) ! "tmp" [C ~> degC]
+        do i=is,ie
+          tmp(i,j,k) = ( ( tv%C_p * GV%H_to_RZ ) * h(i,j,k) ) * tmp(i,j,k) ! "tmp" [ Q R Z ~> J m-2]
+        enddo
+      enddo ; enddo
+    endif
+    call post_data(CS%id_chcint, tmp, CS%diag)
+  endif
+
 end subroutine calculate_vertical_integrals
 
 !> This subroutine calculates terms in the mechanical energy budget.
@@ -1450,20 +1534,20 @@ subroutine post_surface_dyn_diags(IDs, G, diag, sfc_state, ssh)
   is = G%isc ; ie = G%iec ; js = G%jsc ; je = G%jec
 
   if (IDs%id_ssh > 0) &
-    call post_data(IDs%id_ssh, ssh, diag, mask=G%mask2dT)
+    call post_data(IDs%id_ssh, ssh, diag)
 
   if (IDs%id_ssu > 0) &
-    call post_data(IDs%id_ssu, sfc_state%u, diag, mask=G%mask2dCu)
+    call post_data(IDs%id_ssu, sfc_state%u, diag)
 
   if (IDs%id_ssv > 0) &
-    call post_data(IDs%id_ssv, sfc_state%v, diag, mask=G%mask2dCv)
+    call post_data(IDs%id_ssv, sfc_state%v, diag)
 
   if (IDs%id_speed > 0) then
     do j=js,je ; do i=is,ie
       speed(i,j) = sqrt(0.5*((sfc_state%u(I-1,j)**2) + (sfc_state%u(I,j)**2)) + &
                         0.5*((sfc_state%v(i,J-1)**2) + (sfc_state%v(i,J)**2)))
     enddo ; enddo
-    call post_data(IDs%id_speed, speed, diag, mask=G%mask2dT)
+    call post_data(IDs%id_speed, speed, diag)
   endif
 
   if (IDs%id_ssu_east > 0 .or. IDs%id_ssv_north > 0) then
@@ -1473,8 +1557,8 @@ subroutine post_surface_dyn_diags(IDs, G, diag, sfc_state, ssh)
       ssv_north(i,j) = ((0.5*(sfc_state%v(i,J-1) + sfc_state%v(i,J))) * G%cos_rot(i,j)) - &
                        ((0.5*(sfc_state%u(I-1,j) + sfc_state%u(I,j))) * G%sin_rot(i,j))
     enddo ; enddo
-    if (IDs%id_ssu_east > 0 ) call post_data(IDs%id_ssu_east, ssu_east, diag, mask=G%mask2dT)
-    if (IDs%id_ssv_north > 0 ) call post_data(IDs%id_ssv_north, ssv_north, diag, mask=G%mask2dT)
+    if (IDs%id_ssu_east > 0 ) call post_data(IDs%id_ssu_east, ssu_east, diag)
+    if (IDs%id_ssv_north > 0 ) call post_data(IDs%id_ssv_north, ssv_north, diag)
   endif
 
 end subroutine post_surface_dyn_diags
@@ -1522,12 +1606,12 @@ subroutine post_surface_thermo_diags(IDs, G, GV, US, diag, dt_int, sfc_state, tv
     do j=js,je ; do i=is,ie
       zos(i,j) = ssh_ibc(i,j) - G%mask2dT(i,j)*zos_area_mean
     enddo ; enddo
-    if (IDs%id_zos > 0) call post_data(IDs%id_zos, zos, diag, mask=G%mask2dT)
+    if (IDs%id_zos > 0) call post_data(IDs%id_zos, zos, diag)
     if (IDs%id_zossq > 0) then
       do j=js,je ; do i=is,ie
         work_2d(i,j) = zos(i,j)*zos(i,j)
       enddo ; enddo
-      call post_data(IDs%id_zossq, work_2d, diag, mask=G%mask2dT)
+      call post_data(IDs%id_zossq, work_2d, diag)
     endif
   endif
 
@@ -1548,7 +1632,7 @@ subroutine post_surface_thermo_diags(IDs, G, GV, US, diag, dt_int, sfc_state, tv
     do j=js,je ; do i=is,ie
       work_2d(i,j) = tv%frazil(i,j) * I_time_int
     enddo ; enddo
-    call post_data(IDs%id_fraz, work_2d, diag, mask=G%mask2dT)
+    call post_data(IDs%id_fraz, work_2d, diag)
   endif
 
   ! post time-averaged salt deficit
@@ -1556,7 +1640,7 @@ subroutine post_surface_thermo_diags(IDs, G, GV, US, diag, dt_int, sfc_state, tv
     do j=js,je ; do i=is,ie
       work_2d(i,j) = tv%salt_deficit(i,j) * I_time_int
     enddo ; enddo
-    call post_data(IDs%id_salt_deficit, work_2d, diag, mask=G%mask2dT)
+    call post_data(IDs%id_salt_deficit, work_2d, diag)
   endif
 
   ! post temperature of P-E+R
@@ -1564,7 +1648,7 @@ subroutine post_surface_thermo_diags(IDs, G, GV, US, diag, dt_int, sfc_state, tv
     do j=js,je ; do i=is,ie
       work_2d(i,j) = tv%TempxPmE(i,j) * (tv%C_p * I_time_int)
     enddo ; enddo
-    call post_data(IDs%id_Heat_PmE, work_2d, diag, mask=G%mask2dT)
+    call post_data(IDs%id_Heat_PmE, work_2d, diag)
   endif
 
   ! post geothermal heating or internal heat source/sinks
@@ -1572,50 +1656,50 @@ subroutine post_surface_thermo_diags(IDs, G, GV, US, diag, dt_int, sfc_state, tv
     do j=js,je ; do i=is,ie
       work_2d(i,j) = tv%internal_heat(i,j) * (tv%C_p * I_time_int)
     enddo ; enddo
-    call post_data(IDs%id_intern_heat, work_2d, diag, mask=G%mask2dT)
+    call post_data(IDs%id_intern_heat, work_2d, diag)
   endif
 
   if (tv%T_is_conT) then
     ! Internal T&S variables are conservative temperature & absolute salinity
-    if (IDs%id_sstcon > 0) call post_data(IDs%id_sstcon, sfc_state%SST, diag, mask=G%mask2dT)
+    if (IDs%id_sstcon > 0) call post_data(IDs%id_sstcon, sfc_state%SST, diag)
     ! Use TEOS-10 function calls convert T&S diagnostics from conservative temp
     ! to potential temperature.
     EOSdom(:) = EOS_domain(G%HI)
     do j=js,je
       call cons_temp_to_pot_temp(sfc_state%SST(:,j), sfc_state%SSS(:,j), work_2d(:,j), tv%eqn_of_state, EOSdom)
     enddo
-    if (IDs%id_sst > 0) call post_data(IDs%id_sst, work_2d, diag, mask=G%mask2dT)
+    if (IDs%id_sst > 0) call post_data(IDs%id_sst, work_2d, diag)
   else
     ! Internal T&S variables are potential temperature & practical salinity
-    if (IDs%id_sst > 0) call post_data(IDs%id_sst, sfc_state%SST, diag, mask=G%mask2dT)
+    if (IDs%id_sst > 0) call post_data(IDs%id_sst, sfc_state%SST, diag)
   endif
 
   if (tv%S_is_absS) then
     ! Internal T&S variables are conservative temperature & absolute salinity
-    if (IDs%id_sssabs > 0) call post_data(IDs%id_sssabs, sfc_state%SSS, diag, mask=G%mask2dT)
+    if (IDs%id_sssabs > 0) call post_data(IDs%id_sssabs, sfc_state%SSS, diag)
     ! Use TEOS-10 function calls convert T&S diagnostics from absolute salinity
     ! to practical salinity.
     EOSdom(:) = EOS_domain(G%HI)
     do j=js,je
       call abs_saln_to_prac_saln(sfc_state%SSS(:,j), work_2d(:,j), tv%eqn_of_state, EOSdom)
     enddo
-    if (IDs%id_sss > 0) call post_data(IDs%id_sss, work_2d, diag, mask=G%mask2dT)
+    if (IDs%id_sss > 0) call post_data(IDs%id_sss, work_2d, diag)
   else
     ! Internal T&S variables are potential temperature & practical salinity
-    if (IDs%id_sss > 0) call post_data(IDs%id_sss, sfc_state%SSS, diag, mask=G%mask2dT)
+    if (IDs%id_sss > 0) call post_data(IDs%id_sss, sfc_state%SSS, diag)
   endif
 
   if (IDs%id_sst_sq > 0) then
     do j=js,je ; do i=is,ie
       work_2d(i,j) = sfc_state%SST(i,j)*sfc_state%SST(i,j)
     enddo ; enddo
-    call post_data(IDs%id_sst_sq, work_2d, diag, mask=G%mask2dT)
+    call post_data(IDs%id_sst_sq, work_2d, diag)
   endif
   if (IDs%id_sss_sq > 0) then
     do j=js,je ; do i=is,ie
       work_2d(i,j) = sfc_state%SSS(i,j)*sfc_state%SSS(i,j)
     enddo ; enddo
-    call post_data(IDs%id_sss_sq, work_2d, diag, mask=G%mask2dT)
+    call post_data(IDs%id_sss_sq, work_2d, diag)
   endif
 
   call coupler_type_send_data(sfc_state%tr_fields, get_diag_time_end(diag))
@@ -1891,6 +1975,43 @@ subroutine MOM_diagnostics_init(MIS, ADp, CDp, Time, G, GV, US, param_file, diag
     CS%id_abssosga = register_scalar_field('ocean_model', 'ssabss_global', Time, diag, &
         long_name='Global Area Average Sea Surface Absolute Salinity', &
         units='psu', conversion=US%S_to_ppt, standard_name='sea_surface_absolute_salinity')
+
+    ! 2d column integrated
+    CS%id_temp_int = register_diag_field('ocean_model', 'temp_int', diag%axesT1, Time, &
+        'Density weighted column integrated potential temperature', &
+        'degC kg m-2', conversion=US%C_to_degC*US%RZ_to_kg_m2, &
+        cmor_field_name='opottempmint', &
+        cmor_long_name='integral_wrt_depth_of_product_of_sea_water_density_and_potential_temperature', &
+        cmor_standard_name='Depth integrated density times potential temperature')
+    CS%id_salt_int = register_diag_field('ocean_model', 'salt_int', diag%axesT1, Time, &
+        'Density weighted column integrated salinity', &
+        'psu kg m-2', conversion=US%S_to_ppt*US%RZ_to_kg_m2, v_extensive=.true., &
+        cmor_field_name='somint', &
+        cmor_long_name='integral_wrt_depth_of_product_of_sea_water_density_and_salinity', &
+        cmor_standard_name='Depth integrated density times salinity')
+
+    ! 3d vertically integrated
+    CS%id_absscint = register_diag_field('ocean_model', 'absscint', diag%axesTL, Time, &
+        'Integral wrt depth of seawater absolute salinity expressed as salt mass content', &
+        units='kg m-2', conversion=US%S_to_ppt*US%RZ_to_kg_m2, v_extensive=.true., &
+        standard_name='integral_wrt_depth_of_sea_water_absolute_salinity_expressed_as_salt_mass_content')
+    CS%id_pfscint = register_diag_field('ocean_model', 'pfscint', diag%axesTL, Time, &
+        ' Integral wrt depth of seawater preformed salinity expressed as salt mass content', &
+        units='kg m-2', conversion=US%S_to_ppt*US%RZ_to_kg_m2, v_extensive=.true., &
+        standard_name='integral_wrt_depth_of_sea_water_preformed_salinity_expressed_as_salt_mass_content')
+    CS%id_scint = register_diag_field('ocean_model', 'scint', diag%axesTL, Time, &
+        'Integral wrt depth of seawater practical salinity expressed as salt mass content', &
+        units='kg m-2', conversion=US%S_to_ppt*US%RZ_to_kg_m2, v_extensive=.true., &
+        standard_name='integral_wrt_depth_of_sea_water_practical_salinity_expressed_as_salt_mass_content')
+    CS%id_chcint = register_diag_field('ocean_model', 'chcint', diag%axesTL, Time, &
+        'Depth Integrated Seawater Conservative Temperature Expressed As Heat Content', &
+        units='J m-2', conversion=US%Q_to_J_kg*US%RZ_to_kg_m2, v_extensive=.true., &
+        standard_name='integral_wrt_depth_of_sea_water_conservative_temperature_expressed_as_heat_content')
+    CS%id_phcint = register_diag_field('ocean_model', 'phcint', diag%axesTL, Time, &
+        'Integrated Ocean Heat Content from Potential Temperature', &
+        units='J m-2', conversion=US%Q_to_J_kg*US%RZ_to_kg_m2, v_extensive=.true., &
+        standard_name='integral_wrt_depth_of_sea_water_potential_temperature_expressed_as_heat_content')
+
   endif
 
   CS%id_u = register_diag_field('ocean_model', 'u', diag%axesCuL, Time, &
@@ -2077,22 +2198,6 @@ subroutine MOM_diagnostics_init(MIS, ADp, CDp, Time, G, GV, US, param_file, diag
   CS%id_mass_wt = register_diag_field('ocean_model', 'mass_wt', diag%axesT1, Time, &
       'The column mass for calculating mass-weighted average properties', 'kg m-2', conversion=US%RZ_to_kg_m2)
 
-  if (use_temperature) then
-    CS%id_temp_int = register_diag_field('ocean_model', 'temp_int', diag%axesT1, Time, &
-        'Density weighted column integrated potential temperature', &
-        'degC kg m-2', conversion=US%C_to_degC*US%RZ_to_kg_m2, &
-        cmor_field_name='opottempmint', &
-        cmor_long_name='integral_wrt_depth_of_product_of_sea_water_density_and_potential_temperature', &
-        cmor_standard_name='Depth integrated density times potential temperature')
-
-    CS%id_salt_int = register_diag_field('ocean_model', 'salt_int', diag%axesT1, Time, &
-        'Density weighted column integrated salinity', &
-        'psu kg m-2', conversion=US%S_to_ppt*US%RZ_to_kg_m2, &
-        cmor_field_name='somint', &
-        cmor_long_name='integral_wrt_depth_of_product_of_sea_water_density_and_salinity', &
-        cmor_standard_name='Depth integrated density times salinity')
-  endif
-
   CS%id_col_mass = register_diag_field('ocean_model', 'col_mass', diag%axesT1, Time, &
       'The column integrated in situ density', 'kg m-2', conversion=US%RZ_to_kg_m2)
 
@@ -2324,6 +2429,7 @@ subroutine write_static_fields(G, GV, US, tv, diag)
         x_cell_method='mean', y_cell_method='mean', area_cell_method='mean')
   if (id > 0) then
     do j=G%jsc,G%jec ; do i=G%isc,G%iec ; work_2d(i,j) = G%bathyT(i,j)+G%Z_ref ; enddo ; enddo
+    ! A mask argument is required here because masks are not applied to static fields by default.
     call post_data(id, work_2d, diag, .true., mask=G%mask2dT)
   endif
 
diff --git a/src/diagnostics/MOM_sum_output.F90 b/src/diagnostics/MOM_sum_output.F90
index a9a4daecc3..a861f7192f 100644
--- a/src/diagnostics/MOM_sum_output.F90
+++ b/src/diagnostics/MOM_sum_output.F90
@@ -409,9 +409,9 @@ subroutine write_energy(u, v, h, tv, day, n, G, GV, US, CS, tracer_CSp, dt_forci
   real :: QRZL2_to_J   ! The combination of unit rescaling factors to convert integrated heat
                        ! content into mks units [J Q-1 R-1 Z-1 L-2 ~> 1]
   real :: J_to_QRZL2   ! The combination of unit rescaling factors to rescale integrated heat
-                       ! content from mks units into the internal units of MOM6 [Q R Z L J-1 ~> 1]
+                       ! content from mks units into the internal units of MOM6 [Q R Z L2 J-1 ~> 1]
   real :: kg_to_RZL2   ! The combination of unit rescaling factors to rescale masses from
-                       ! mks units into the internal units of MOM6 [R Z L kg-1 ~> 1]
+                       ! mks units into the internal units of MOM6 [R Z L2 kg-1 ~> 1]
   real :: salt_to_kg   ! A factor used to rescale salt contents [kg R-1 Z-1 L-2 ~> nondim]
   integer :: num_nc_fields  ! The number of fields that will actually go into
                             ! the NetCDF file.
diff --git a/src/diagnostics/MOM_wave_speed.F90 b/src/diagnostics/MOM_wave_speed.F90
index 7abdab0a90..025c25de06 100644
--- a/src/diagnostics/MOM_wave_speed.F90
+++ b/src/diagnostics/MOM_wave_speed.F90
@@ -135,7 +135,7 @@ subroutine wave_speed(h, tv, G, GV, US, cg1, CS, halo_size, use_ebt_mode, mono_N
   real :: I_Hnew   ! The inverse of a new layer thickness [H-1 ~> m-1 or m2 kg-1]
   real :: drxh_sum ! The sum of density differences across interfaces times thicknesses [R H ~> kg m-2 or kg2 m-5]
   real :: dSpVxh_sum ! The sum of specific volume differences across interfaces times
-                   ! thicknesses [R-1 H ~> m4 kg-1 or m], negative for stable stratification.
+                   ! thicknesses [H R-1 ~> m4 kg-1 or m], negative for stable stratification.
   real :: g_Rho0   ! G_Earth/Rho0 [L2 T-2 H-1 R-1 ~> m4 s-2 kg-1 or m7 s-2 kg-2].
   real :: c2_scale ! A scaling factor for wave speeds to help control the growth of the determinant and
                    ! its derivative with lam between rows of the Thomas algorithm solver [L2 s2 T-2 m-2 ~> nondim].
@@ -550,8 +550,9 @@ subroutine wave_speed(h, tv, G, GV, US, cg1, CS, halo_size, use_ebt_mode, mono_N
                 ! Determine whether N2 estimates should not be allowed to increase with depth.
                 if (l_mono_N2_column_fraction>0.) then
                   if (GV%Boussinesq .or. GV%semi_Boussinesq) then
-                    below_mono_N2_frac = ((G%bathyT(i,j)+G%Z_ref) - GV%H_to_Z*sum_hc < &
-                                          l_mono_N2_column_fraction*(G%bathyT(i,j)+G%Z_ref))
+                    below_mono_N2_frac = &
+                        (max(G%meanSL(i,j) + G%bathyT(i,j), 0.0) - GV%H_to_Z * sum_hc < &
+                         l_mono_N2_column_fraction * max(G%meanSL(i,j) + G%bathyT(i,j), 0.0))
                   else
                     below_mono_N2_frac = (htot(i) - sum_hc < l_mono_N2_column_fraction*htot(i))
                   endif
@@ -852,7 +853,7 @@ subroutine wave_speeds(h, tv, G, GV, US, nmodes, cn, CS, w_struct, u_struct, u_s
   real :: I_Hnew     ! The inverse of a new layer thickness [H-1 ~> m-1 or m2 kg-1]
   real :: drxh_sum   ! The sum of density differences across interfaces times thicknesses [R H ~> kg m-2 or kg2 m-5]
   real :: dSpVxh_sum ! The sum of specific volume differences across interfaces times
-                     ! thicknesses [R-1 H ~> m4 kg-1 or m], negative for stable stratification.
+                     ! thicknesses [H R-1 ~> m4 kg-1 or m], negative for stable stratification.
   real :: g_Rho0     ! G_Earth/Rho0 [L2 T-2 H-1 R-1 ~> m4 s-2 kg-1 or m7 s-2 kg-2].
   real :: tol_Hfrac  ! Layers that together are smaller than this fraction of
                      ! the total water column can be merged for efficiency [nondim].
@@ -879,13 +880,10 @@ subroutine wave_speeds(h, tv, G, GV, US, nmodes, cn, CS, w_struct, u_struct, u_s
   real :: mode_struct(SZK_(GV)+1) ! The mode structure [nondim], but it is also temporarily
                          ! in units of [L2 T-2 ~> m2 s-2] after it is modified inside of tdma6.
   real :: mode_struct_fder(SZK_(GV)) ! The mode structure 1st derivative [Z-1 ~> m-1], but it is also temporarily
-                         ! in units of [Z-1 L2 T-2 ~> m s-2] after it is modified inside of tdma6.
+                         ! in units of [L2 Z-1 T-2 ~> m s-2] after it is modified inside of tdma6.
   real :: mode_struct_sq(SZK_(GV)+1) ! The square of mode structure [nondim]
   real :: mode_struct_fder_sq(SZK_(GV)) ! The square of mode structure 1st derivative [Z-2 ~> m-2]
 
-
-  real :: ms_min, ms_max ! The minimum and maximum mode structure values returned from tdma6 [L2 T-2 ~> m2 s-2]
-  real :: ms_sq          ! The sum of the square of the values returned from tdma6 [L4 T-4 ~> m4 s-4]
   real :: w2avg          ! A total for renormalization [H L4 T-4 ~> m5 s-4 or kg m2 s-4]
   real, parameter :: a_int = 0.5 ! Integral total for normalization [nondim]
   real :: renorm         ! Normalization factor [T2 L-2 ~> s2 m-2]
diff --git a/src/equation_of_state/MOM_EOS.F90 b/src/equation_of_state/MOM_EOS.F90
index ee49bd282d..e8560d8ea2 100644
--- a/src/equation_of_state/MOM_EOS.F90
+++ b/src/equation_of_state/MOM_EOS.F90
@@ -50,7 +50,9 @@ module MOM_EOS
 public calculate_TFreeze
 public convert_temp_salt_for_TEOS10
 public cons_temp_to_pot_temp
+public pot_temp_to_cons_temp
 public abs_saln_to_prac_saln
+public prac_saln_to_abs_saln
 public gsw_sp_from_sr
 public gsw_sr_from_sp
 public gsw_pt_from_ct
@@ -416,7 +418,6 @@ subroutine calculate_spec_vol_array(T, S, pressure, specvol, start, npts, EOS, s
   real,     optional, intent(in)    :: scale    !< A multiplicative factor by which to scale specific
                                                 !! volume in combination with scaling stored in EOS [various]
 
-  real, dimension(size(specvol))  :: rho   ! Density [kg m-3]
   integer :: j
 
   if (.not. allocated(EOS%type)) call MOM_error(FATAL, &
@@ -851,8 +852,6 @@ subroutine calculate_density_derivs_scalar(T, S, pressure, drho_dT, drho_dS, EOS
   real :: pres(1)  ! Pressure converted to [Pa]
   real :: Ta(1)    ! Temperature converted to [degC]
   real :: Sa(1)    ! Salinity converted to [ppt]
-  real :: dR_dT(1) ! A copy of drho_dT in mks units [kg m-3 degC-1]
-  real :: dR_dS(1) ! A copy of drho_dS in mks units [kg m-3 ppt-1]
 
   pres(1) = EOS%RL2_T2_to_Pa*pressure
   Ta(1) = EOS%C_to_degC * T
@@ -1956,7 +1955,6 @@ subroutine abs_saln_to_prac_saln(S, prSaln, EOS, dom, scale)
                                                 !! while the default is equivalent to EOS%ppt_to_S.
 
   ! Local variables
-  real, dimension(size(S)) :: Sa    ! Salinity converted to [ppt]
   real :: S_scale ! A factor to convert practical salinity from ppt to the desired units [S PSU-1 ~> 1]
   real, parameter :: Sprac_Sref = (35.0/35.16504) ! The TEOS 10 conversion factor to go from
                                     ! reference salinity to practical salinity [PSU ppt-1]
@@ -1997,7 +1995,6 @@ subroutine prac_saln_to_abs_saln(S, absSaln, EOS, dom, scale)
                                                 !! while the default is equivalent to EOS%ppt_to_S.
 
   ! Local variables
-  real, dimension(size(S)) :: Sp    ! Salinity converted to [ppt]
   real :: S_scale ! A factor to convert absolute salinity from ppt to the desired units [S ppt-1 ~> 1]
   real, parameter :: Sref_Sprac = (35.16504/35.0) ! The TEOS 10 conversion factor to go from
                                     ! practical salinity to reference salinity [PSU ppt-1]
@@ -2186,7 +2183,6 @@ logical function test_TS_conversion_consistency(T_cons, S_abs, T_pot, S_prac, EO
   real :: Ttol     ! Roundoff error on a typical value of temperatures [degC]
   logical :: test_OK ! True if a particular test is consistent.
   logical :: OK      ! True if all checks so far are consistent.
-  integer :: i, j, n
 
   OK = .true.
 
@@ -2234,7 +2230,6 @@ logical function test_TFr_consistency(S_test, p_test, EOS, verbose, EOS_name, TF
   real, dimension(-3:3,-3:3) :: S ! Salinities at the test value and perturbed points [S ~> ppt]
   real, dimension(-3:3,-3:3) :: P ! Pressures at the test value and perturbed points [R L2 T-2 ~> Pa]
   real, dimension(-3:3,-3:3,2) :: TFr ! Freezing point at the test value and perturbed points [C ~> degC]
-  character(len=200) :: mesg
   real :: dS         ! Magnitude of salinity perturbations [S ~> ppt]
   real :: dp         ! Magnitude of pressure perturbations [R L2 T-2 ~> Pa]
   ! real :: tol        ! The nondimensional tolerance from roundoff [nondim]
diff --git a/src/equation_of_state/MOM_EOS_Wright.F90 b/src/equation_of_state/MOM_EOS_Wright.F90
index 874d3e784e..938fa07200 100644
--- a/src/equation_of_state/MOM_EOS_Wright.F90
+++ b/src/equation_of_state/MOM_EOS_Wright.F90
@@ -719,7 +719,7 @@ subroutine int_spec_vol_dp_wright(T, S, p_t, p_b, spv_ref, HI, dza, &
   real :: al0        ! A term in the Wright EOS [R-1 ~> m3 kg-1]
   real :: p0         ! A term in the Wright EOS [R L2 T-2 ~> Pa]
   real :: lambda     ! A term in the Wright EOS [L2 T-2 ~> m2 s-2]
-  real :: al0_scale  ! Scaling factor to convert al0 from MKS units [R-1 kg m-3 ~> 1]
+  real :: al0_scale  ! Scaling factor to convert al0 from MKS units [kg m-3 R-1 ~> 1]
   real :: p0_scale   ! Scaling factor to convert p0 from MKS units [R L2 T-2 Pa-1 ~> 1]
   real :: lam_scale  ! Scaling factor to convert lambda from MKS units [L2 s2 T-2 m-2 ~> 1]
   real :: p_ave      ! The layer average pressure [R L2 T-2 ~> Pa]
diff --git a/src/equation_of_state/MOM_EOS_Wright_full.F90 b/src/equation_of_state/MOM_EOS_Wright_full.F90
index 4be5f2940e..fdbe01eb15 100644
--- a/src/equation_of_state/MOM_EOS_Wright_full.F90
+++ b/src/equation_of_state/MOM_EOS_Wright_full.F90
@@ -724,7 +724,7 @@ subroutine int_spec_vol_dp_wright_full(T, S, p_t, p_b, spv_ref, HI, dza, &
   real :: al0        ! A term in the Wright EOS [R-1 ~> m3 kg-1]
   real :: p0         ! A term in the Wright EOS [R L2 T-2 ~> Pa]
   real :: lambda     ! A term in the Wright EOS [L2 T-2 ~> m2 s-2]
-  real :: al0_scale  ! Scaling factor to convert al0 from MKS units [R-1 kg m-3 ~> 1]
+  real :: al0_scale  ! Scaling factor to convert al0 from MKS units [kg m-3 R-1 ~> 1]
   real :: p0_scale   ! Scaling factor to convert p0 from MKS units [R L2 T-2 Pa-1 ~> 1]
   real :: lam_scale  ! Scaling factor to convert lambda from MKS units [L2 s2 T-2 m-2 ~> 1]
   real :: p_ave      ! The layer average pressure [R L2 T-2 ~> Pa]
diff --git a/src/equation_of_state/MOM_EOS_Wright_red.F90 b/src/equation_of_state/MOM_EOS_Wright_red.F90
index 1635f9e809..996d838f12 100644
--- a/src/equation_of_state/MOM_EOS_Wright_red.F90
+++ b/src/equation_of_state/MOM_EOS_Wright_red.F90
@@ -726,7 +726,7 @@ subroutine int_spec_vol_dp_wright_red(T, S, p_t, p_b, spv_ref, HI, dza, &
   real :: al0        ! A term in the Wright EOS [R-1 ~> m3 kg-1]
   real :: p0         ! A term in the Wright EOS [R L2 T-2 ~> Pa]
   real :: lambda     ! A term in the Wright EOS [L2 T-2 ~> m2 s-2]
-  real :: al0_scale  ! Scaling factor to convert al0 from MKS units [R-1 kg m-3 ~> 1]
+  real :: al0_scale  ! Scaling factor to convert al0 from MKS units [kg m-3 R-1 ~> 1]
   real :: p0_scale   ! Scaling factor to convert p0 from MKS units [R L2 T-2 Pa-1 ~> 1]
   real :: lam_scale  ! Scaling factor to convert lambda from MKS units [L2 s2 T-2 m-2 ~> 1]
   real :: p_ave      ! The layer average pressure [R L2 T-2 ~> Pa]
diff --git a/src/framework/MOM_checksums.F90 b/src/framework/MOM_checksums.F90
index 9177eb8965..837c634e9b 100644
--- a/src/framework/MOM_checksums.F90
+++ b/src/framework/MOM_checksums.F90
@@ -2192,7 +2192,7 @@ end subroutine chksum_v_3d
 
 !> chksum1d does a checksum of a 1-dimensional array.
 subroutine chksum1d(array, mesg, start_i, end_i, compare_PEs, logunit)
-  real, dimension(:), intent(in) :: array   !< The array to be summed (index starts at 1) [abitrary].
+  real, dimension(:), intent(in) :: array   !< The array to be summed (index starts at 1) in arbitrary units [A].
   character(len=*),   intent(in) :: mesg    !< An identifying message.
   integer, optional,  intent(in) :: start_i !< The starting index for the sum (default 1)
   integer, optional,  intent(in) :: end_i   !< The ending index for the sum (default all)
@@ -2201,8 +2201,8 @@ subroutine chksum1d(array, mesg, start_i, end_i, compare_PEs, logunit)
   integer, optional,  intent(in) :: logunit !< IO unit for checksum logging
 
   integer :: is, ie, i, bc, sum1, sum_bc, ioUnit
-  real :: sum  ! The global sum of the array [arbitrary]
-  real, allocatable :: sum_here(:) ! The sum on each PE [arbitrary]
+  real :: sum  ! The global sum of the array [A]
+  real, allocatable :: sum_here(:) ! The sum on each PE [A]
   logical :: compare
   integer :: pe_num   ! pe number of the data
   integer :: nPEs     ! Total number of processsors
@@ -2253,12 +2253,12 @@ end subroutine chksum1d
 !> chksum2d does a checksum of all data in a 2-d array.
 subroutine chksum2d(array, mesg, logunit)
 
-  real, dimension(:,:), intent(in) :: array !< The array to be checksummed [arbitrary]
+  real, dimension(:,:), intent(in) :: array !< The array to be checksummed in arbitrary units [A]
   character(len=*),     intent(in) :: mesg  !< An identifying message
   integer,    optional, intent(in) :: logunit !< IO unit for checksum logging
 
   integer :: xs, xe, ys, ye, i, j, sum1, bc, iounit
-  real :: sum  ! The global sum of the array [arbitrary]
+  real :: sum  ! The global sum of the array [A]
 
   iounit = error_unit ; if (present(logunit)) iounit = logunit
 
@@ -2284,12 +2284,12 @@ end subroutine chksum2d
 !> chksum3d does a checksum of all data in a 2-d array.
 subroutine chksum3d(array, mesg, logunit)
 
-  real, dimension(:,:,:), intent(in) :: array !< The array to be checksummed [arbitrary]
+  real, dimension(:,:,:), intent(in) :: array !< The array to be checksummed in arbitrary units [A]
   character(len=*),       intent(in) :: mesg  !< An identifying message
   integer,      optional, intent(in) :: logunit !< IO unit for checksum logging
 
   integer :: xs, xe, ys, ye, zs, ze, i, j, k, bc, sum1, iounit
-  real :: sum  ! The global sum of the array [arbitrary]
+  real :: sum  ! The global sum of the array [A]
 
   iounit = error_unit ; if (present(logunit)) iounit = logunit
 
@@ -2315,7 +2315,7 @@ end subroutine chksum3d
 
 !> This function returns .true. if x is a NaN, and .false. otherwise.
 function is_NaN_0d(x)
-  real, intent(in) :: x !< The value to be checked for NaNs [arbitrary]
+  real, intent(in) :: x !< The value to be checked for NaNs in arbitrary units [A]
   logical :: is_NaN_0d
 
  !is_NaN_0d = (((x < 0.0) .and. (x >= 0.0)) .or. &
@@ -2331,7 +2331,7 @@ end function is_NaN_0d
 
 !> Returns .true. if any element of x is a NaN, and .false. otherwise.
 function is_NaN_1d(x, skip_mpp)
-  real, dimension(:), intent(in) :: x !< The array to be checked for NaNs [arbitrary]
+  real, dimension(:), intent(in) :: x !< The array to be checked for NaNs in arbitrary units [A]
   logical,  optional, intent(in) :: skip_mpp  !< If true, only check this array only
                                               !! on the local PE (default false).
   logical :: is_NaN_1d
@@ -2354,7 +2354,7 @@ end function is_NaN_1d
 
 !> Returns .true. if any element of x is a NaN, and .false. otherwise.
 function is_NaN_2d(x)
-  real, dimension(:,:), intent(in) :: x !< The array to be checked for NaNs [arbitrary]
+  real, dimension(:,:), intent(in) :: x !< The array to be checked for NaNs in arbitrary units [A]
   logical :: is_NaN_2d
 
   integer :: i, j, n
@@ -2371,7 +2371,7 @@ end function is_NaN_2d
 
 !> Returns .true. if any element of x is a NaN, and .false. otherwise.
 function is_NaN_3d(x)
-  real, dimension(:,:,:), intent(in) :: x !< The array to be checked for NaNs [arbitrary]
+  real, dimension(:,:,:), intent(in) :: x !< The array to be checked for NaNs in arbitrary units [A]
   logical :: is_NaN_3d
 
   integer :: i, j, k, n
@@ -2454,7 +2454,7 @@ function field_checksum_real_2d(field, pelist, mask_val, turns, unscale) &
   integer(kind=int64) :: chksum                     !< checksum of array
 
   ! Local variables
-  real, allocatable :: field_rot(:,:)  ! A rotated version of field, with the same units [arbitrary]
+  real, allocatable :: field_rot(:,:)  ! A rotated version of field, with the same units [A ~> a]
   integer :: qturns ! The number of quarter turns through which to rotate field
   logical :: do_unscale ! If true, unscale the variable before it is checksummed
 
@@ -2494,7 +2494,7 @@ function field_checksum_real_3d(field, pelist, mask_val, turns, unscale) &
   integer(kind=int64) :: chksum                     !< checksum of array
 
   ! Local variables
-  real, allocatable :: field_rot(:,:,:)  ! A rotated version of field, with the same units [arbitrary]
+  real, allocatable :: field_rot(:,:,:)  ! A rotated version of field, with the same units [A ~> a]
   integer :: qturns ! The number of quarter turns through which to rotate field
   logical :: do_unscale ! If true, unscale the variable before it is checksummed
 
@@ -2534,7 +2534,7 @@ function field_checksum_real_4d(field, pelist, mask_val, turns, unscale) &
   integer(kind=int64) :: chksum                     !< checksum of array
 
   ! Local variables
-  real, allocatable :: field_rot(:,:,:,:)  ! A rotated version of field, with the same units [arbitrary]
+  real, allocatable :: field_rot(:,:,:,:)  ! A rotated version of field, with the same units [A ~> a]
   integer :: qturns ! The number of quarter turns through which to rotate field
   logical :: do_unscale ! If true, unscale the variable before it is checksummed
 
@@ -2641,9 +2641,9 @@ end subroutine chk_sum_msg2
 subroutine chk_sum_msg3(fmsg, aMean, aMin, aMax, mesg, iounit)
   character(len=*), intent(in) :: fmsg !< A checksum code-location specific preamble
   character(len=*), intent(in) :: mesg !< An identifying message supplied by top-level caller
-  real,             intent(in) :: aMean !< The mean value of the array [arbitrary]
-  real,             intent(in) :: aMin !< The minimum value of the array [arbitrary]
-  real,             intent(in) :: aMax !< The maximum value of the array [arbitrary]
+  real,             intent(in) :: aMean !< The mean value of the array in arbitrary units [A]
+  real,             intent(in) :: aMin !< The minimum value of the array [A]
+  real,             intent(in) :: aMax !< The maximum value of the array [A]
   integer,          intent(in) :: iounit !< Checksum logger IO unit
 
   ! NOTE: We add zero to aMin and aMax to remove any negative zeros.
@@ -2676,7 +2676,7 @@ end subroutine chksum_error
 !> Does a bitcount of a number by first casting to an integer and then using BTEST
 !! to check bit by bit
 integer function bitcount(x)
-  real, intent(in) :: x !< Number to be bitcount [arbitrary]
+  real, intent(in) :: x !< Number to be bitcount in arbitrary units [A]
 
   integer, parameter :: xk = kind(x)  !< Kind type of x
 
diff --git a/src/framework/MOM_coms.F90 b/src/framework/MOM_coms.F90
index be9c9d9586..b0f4f2e575 100644
--- a/src/framework/MOM_coms.F90
+++ b/src/framework/MOM_coms.F90
@@ -359,7 +359,7 @@ function reproducing_sum_3d(array, isr, ier, jsr, jer, sums, EFP_sum, EFP_lay_su
   integer,            optional, intent(in)  :: jer     !< The ending j-index of the sum, noting
                                                        !! that the array indices starts at 1
   real, dimension(:), optional, intent(out) :: sums    !< The sums by vertical layer in the same
-                                                       !! abitrary units as array [a] or [A ~> a]
+                                                       !! arbitrary units as array [a] or [A ~> a]
   type(EFP_type),     optional, intent(out) :: EFP_sum !< The result in extended fixed point format
   type(EFP_type), dimension(:), &
                       optional, intent(out) :: EFP_lay_sums !< The sums by vertical layer in EFP format
@@ -796,7 +796,7 @@ end subroutine EFP_assign
 !> Return the real number that an extended-fixed-point number corresponds with
 function EFP_to_real(EFP1)
   type(EFP_type), intent(inout) :: EFP1 !< The extended fixed point number being converted
-  real :: EFP_to_real  !< The real version of the number in abitrary units [a]
+  real :: EFP_to_real  !< The real version of the number in arbitrary units [a]
 
   call regularize_ints(EFP1%v)
   EFP_to_real = ints_to_real(EFP1%v)
diff --git a/src/framework/MOM_diag_mediator.F90 b/src/framework/MOM_diag_mediator.F90
index 58b7d39a4c..ed3fb907db 100644
--- a/src/framework/MOM_diag_mediator.F90
+++ b/src/framework/MOM_diag_mediator.F90
@@ -29,7 +29,7 @@ module MOM_diag_mediator
 use MOM_io,               only : slasher, vardesc, query_vardesc, MOM_read_data
 use MOM_io,               only : get_filename_appendix
 use MOM_safe_alloc,       only : safe_alloc_ptr, safe_alloc_alloc
-use MOM_string_functions, only : lowercase
+use MOM_string_functions, only : lowercase, ints_to_string, trim_trailing_commas
 use MOM_time_manager,     only : time_type
 use MOM_time_manager,     only : get_time
 use MOM_unit_scaling,     only : unit_scale_type
@@ -1056,7 +1056,7 @@ subroutine define_axes_group(diag_cs, handles, axes, nz, vertical_coordinate_num
   n = size(handles)
   if (n<1 .or. n>3) call MOM_error(FATAL, "define_axes_group: wrong size for list of handles!")
   allocate( axes%handles(n) )
-  axes%id = i2s(handles, n) ! Identifying string
+  axes%id = ints_to_string(handles, max(n,3)) ! Identifying string
   axes%rank = n
   axes%handles(:) = handles(:)
   axes%diag_cs => diag_cs ! A [circular] link back to the diag_cs structure
@@ -1169,7 +1169,7 @@ subroutine define_axes_group_dsamp(diag_cs, handles, axes, dl, nz, vertical_coor
   n = size(handles)
   if (n<1 .or. n>3) call MOM_error(FATAL, "define_axes_group: wrong size for list of handles!")
   allocate( axes%handles(n) )
-  axes%id = i2s(handles, n) ! Identifying string
+  axes%id = ints_to_string(handles, max(n,3)) ! Identifying string
   axes%rank = n
   axes%handles(:) = handles(:)
   axes%diag_cs => diag_cs ! A [circular] link back to the diag_cs structure
@@ -1356,11 +1356,7 @@ subroutine post_data_1d_k(diag_field_id, field, diag_cs, is_static)
       allocate( locfield( ks:ke ) )
 
       do k=ks,ke
-        if (field(k) == diag_cs%missing_value) then
-          locfield(k) = diag_cs%missing_value
-        else
-          locfield(k) = field(k) * diag%conversion_factor
-        endif
+        locfield(k) = field(k) * diag%conversion_factor
       enddo
     else
       locfield => field
@@ -1482,25 +1478,20 @@ subroutine post_data_2d_low(diag, field, diag_cs, is_static, mask)
   if ((diag%conversion_factor /= 0.) .and. (diag%conversion_factor /= 1.)) then
     allocate( locfield( lbound(field,1):ubound(field,1), lbound(field,2):ubound(field,2) ) )
     do j=jsv,jev ; do i=isv,iev
-      if (field(i,j) == diag_cs%missing_value) then
-        locfield(i,j) = diag_cs%missing_value
-      else
-        locfield(i,j) = field(i,j) * diag%conversion_factor
-      endif
+      locfield(i,j) = field(i,j) * diag%conversion_factor
     enddo ; enddo
-    locfield(isv:iev,jsv:jev) = field(isv:iev,jsv:jev) * diag%conversion_factor
   else
     locfield => field
   endif
 
   if (present(mask)) then
     locmask => mask
-  elseif (.NOT. is_stat) then
+  elseif (.NOT. is_stat .and. associated(diag%axes)) then
     if (associated(diag%axes%mask2d)) locmask => diag%axes%mask2d
   endif
 
   dl=1
-  if (.NOT. is_stat) dl = diag%axes%downsample_level !static field downsample i not supported yet
+  if (.NOT. is_stat .and. associated(diag%axes)) dl = diag%axes%downsample_level !static field downsample not supported
   !Downsample the diag field and mask (if present)
   if (dl > 1) then
     isv_o = isv ; jsv_o = jsv
@@ -1829,11 +1820,7 @@ subroutine post_data_3d_low(diag, field, diag_cs, is_static, mask)
     endif
 
     do k=ks,ke ; do j=jsv,jev ; do i=isv,iev
-      if (field(i,j,k) == diag_cs%missing_value) then
-        locfield(i,j,k) = diag_cs%missing_value
-      else
-        locfield(i,j,k) = field(i,j,k) * diag%conversion_factor
-      endif
+      locfield(i,j,k) = field(i,j,k) * diag%conversion_factor
     enddo ; enddo ; enddo
   else
     locfield => field
@@ -2437,14 +2424,7 @@ integer function register_diag_field(module_name, field_name, axes_in, init_time
   if (axes_in%is_v_point)   dimensions = trim(dimensions)//" xh, yq,"
   if (axes_in%is_layer)     dimensions = trim(dimensions)//" zl,"
   if (axes_in%is_interface) dimensions = trim(dimensions)//" zi,"
-
-  if (len_trim(dimensions) > 0) then
-    dimensions = trim(adjustl(dimensions))
-    if (dimensions(len_trim(dimensions):len_trim(dimensions)) == ",") then
-        dimensions = dimensions(1:len_trim(dimensions) - 1)
-    endif
-    dimensions = trim(dimensions)
-  endif
+  if (len_trim(dimensions) > 0) dimensions = trim_trailing_commas(dimensions)
 
   if (is_root_pe() .and. (diag_CS%available_diag_doc_unit > 0)) then
     msg = ''
@@ -3181,14 +3161,7 @@ function register_static_field(module_name, field_name, axes, &
   if (axes%is_v_point)   dimensions = trim(dimensions)//" xh, yq,"
   if (axes%is_layer)     dimensions = trim(dimensions)//" zl,"
   if (axes%is_interface) dimensions = trim(dimensions)//" zi,"
-
-  if (len_trim(dimensions) > 0) then
-    dimensions = trim(adjustl(dimensions))
-    if (dimensions(len_trim(dimensions):len_trim(dimensions)) == ",") then
-        dimensions = dimensions(1:len_trim(dimensions) - 1)
-    endif
-    dimensions = trim(dimensions)
-  endif
+  if (len_trim(dimensions) > 0) dimensions = trim_trailing_commas(dimensions)
 
   ! Document diagnostics in list of available diagnostics
   if (is_root_pe() .and. diag_CS%available_diag_doc_unit > 0) then
@@ -3860,28 +3833,6 @@ subroutine diag_mediator_end(time, diag_CS, end_diag_manager)
 
 end subroutine diag_mediator_end
 
-!> Convert the first n elements (up to 3) of an integer array to an underscore delimited string.
-function i2s(a,n_in)
-  ! "Convert the first n elements of an integer array to a string."
-  ! Perhaps this belongs elsewhere in the MOM6 code?
-  integer, dimension(:), intent(in) :: a    !< The array of integers to translate
-  integer, optional    , intent(in) :: n_in !< The number of elements to translate, by default all
-  character(len=15) :: i2s !< The returned string
-
-  character(len=15) :: i2s_temp
-  integer :: i,n
-
-  n=size(a)
-  if (present(n_in)) n = n_in
-
-  i2s = ''
-  do i=1,min(n,3)
-    write (i2s_temp, '(I4.4)') a(i)
-    i2s = trim(i2s) //'_'// trim(i2s_temp)
-  enddo
-  i2s = adjustl(i2s)
-end function i2s
-
 !> Returns a new diagnostic id, it may be necessary to expand the diagnostics array.
 integer function get_new_diag_id(diag_cs)
   type(diag_ctrl), intent(inout) :: diag_cs !< Diagnostics control structure
diff --git a/src/framework/MOM_dyn_horgrid.F90 b/src/framework/MOM_dyn_horgrid.F90
index 2e183cdbef..b599031e78 100644
--- a/src/framework/MOM_dyn_horgrid.F90
+++ b/src/framework/MOM_dyn_horgrid.F90
@@ -92,6 +92,7 @@ module MOM_dyn_horgrid
     geoLonCu, &  !< The geographic longitude at u points [degrees of longitude] or [m].
     dxCu, &      !< dxCu is delta x at u points [L ~> m].
     IdxCu, &     !< 1/dxCu [L-1 ~> m-1].
+    IdxCu_OBCmask, & !< 1/dxCu or 0 at boundary or OBC points [L-1 ~> m-1].
     dyCu, &      !< dyCu is delta y at u points [L ~> m].
     IdyCu, &     !< 1/dyCu [L-1 ~> m-1].
     dy_Cu, &     !< The unblocked lengths of the u-faces of the h-cell [L ~> m].
@@ -107,6 +108,7 @@ module MOM_dyn_horgrid
     IdxCv, &     !< 1/dxCv [L-1 ~> m-1].
     dyCv, &      !< dyCv is delta y at v points [L ~> m].
     IdyCv, &     !< 1/dyCv [L-1 ~> m-1].
+    IdyCv_OBCmask, & !< 1/dxCv or 0 at boundary or OBC points [L-1 ~> m-1].
     dx_Cv, &     !< The unblocked lengths of the v-faces of the h-cell [L ~> m].
     IareaCv, &   !< The masked inverse areas of v-grid cells [L-2 ~> m-2].
     areaCv       !< The areas of the v-grid cells [L2 ~> m2].
@@ -157,7 +159,16 @@ module MOM_dyn_horgrid
     y_ax_unit_short     !< A short description of the y-axis units for documenting parameter units
 
   real, allocatable, dimension(:,:) :: &
-    bathyT        !< Ocean bottom depth at tracer points, in depth units [Z ~> m].
+    bathyT        !< Ocean bottom depth, referenced to a zero reference height at tracer points.
+                  !! bathyT is in depth units and positive *below* the reference height [Z ~> m].
+  real, allocatable, dimension(:,:) :: &
+    meanSL        !< Spatially varying time mean sea level, referenced to a zero reference height
+                  !! at tracer points. meanSL is in height units and positive *above* zero. It is used
+                  !! a) as the height where p = p_atm or zero;
+                  !! b) to calculate time mean thickness of the water column, where
+                  !!    mean thickness = max(meanSL + bathyT, 0.0).
+                  !! meanSL is 2D for the consideration of a domain with spatically varying mean
+                  !! height, e.g. the Great Lakes system [Z ~> m].
 
   logical :: bathymetry_at_vel  !< If true, there are separate values for the
                   !! basin depths at velocity points.  Otherwise the effects of
@@ -242,6 +253,7 @@ subroutine create_dyn_horgrid(G, HI, bathymetry_at_vel)
   allocate(G%dxBu(IsdB:IedB,JsdB:JedB), source=0.0)
   allocate(G%IdxT(isd:ied,jsd:jed), source=0.0)
   allocate(G%IdxCu(IsdB:IedB,jsd:jed), source=0.0)
+  allocate(G%IdxCu_OBCmask(IsdB:IedB,jsd:jed), source=0.0)
   allocate(G%IdxCv(isd:ied,JsdB:JedB), source=0.0)
   allocate(G%IdxBu(IsdB:IedB,JsdB:JedB), source=0.0)
 
@@ -252,6 +264,7 @@ subroutine create_dyn_horgrid(G, HI, bathymetry_at_vel)
   allocate(G%IdyT(isd:ied,jsd:jed), source=0.0)
   allocate(G%IdyCu(IsdB:IedB,jsd:jed), source=0.0)
   allocate(G%IdyCv(isd:ied,JsdB:JedB), source=0.0)
+  allocate(G%IdyCv_OBCmask(isd:ied,JsdB:JedB), source=0.0)
   allocate(G%IdyBu(IsdB:IedB,JsdB:JedB), source=0.0)
 
   allocate(G%areaT(isd:ied,jsd:jed), source=0.0)
@@ -290,8 +303,8 @@ subroutine create_dyn_horgrid(G, HI, bathymetry_at_vel)
   allocate(G%porous_DmaxV(isd:ied,JsdB:JedB), source=0.0)
   allocate(G%porous_DavgV(isd:ied,JsdB:JedB), source=0.0)
 
-
   allocate(G%bathyT(isd:ied, jsd:jed), source=0.0)
+  allocate(G%meanSL(isd:ied, jsd:jed), source=0.0)
   allocate(G%CoriolisBu(IsdB:IedB, JsdB:JedB), source=0.0)
   allocate(G%Coriolis2Bu(IsdB:IedB, JsdB:JedB), source=0.0)
   allocate(G%dF_dx(isd:ied, jsd:jed), source=0.0)
@@ -333,6 +346,7 @@ subroutine rotate_dyn_horgrid(G_in, G, US, turns)
   call rotate_array_pair(G_in%dxT, G_in%dyT, turns, G%dxT, G%dyT)
   call rotate_array(G_in%areaT, turns, G%areaT)
   call rotate_array(G_in%bathyT, turns, G%bathyT)
+  call rotate_array(G_in%meanSL, turns, G%meanSL)
 
   call rotate_array_pair(G_in%df_dx, G_in%df_dy, turns, G%df_dx, G%df_dy)
   call rotate_array(G_in%sin_rot, turns, G%sin_rot)
@@ -435,6 +449,7 @@ subroutine rescale_dyn_horgrid_bathymetry(G, m_in_new_units)
   rescale = 1.0 / m_in_new_units
   do j=jsd,jed ; do i=isd,ied
     G%bathyT(i,j) = rescale*G%bathyT(i,j)
+    G%meanSL(i,j) = rescale*G%meanSL(i,j)
   enddo ; enddo
   if (G%bathymetry_at_vel) then ; do j=jsd,jed ; do I=IsdB,IedB
     G%Dblock_u(I,j) = rescale*G%Dblock_u(I,j) ; G%Dopen_u(I,j) = rescale*G%Dopen_u(I,j)
@@ -471,6 +486,7 @@ subroutine set_derived_dyn_horgrid(G, US)
     if (G%dyCu(I,j) < 0.0) G%dyCu(I,j) = 0.0
     G%IdxCu(I,j) = Adcroft_reciprocal(G%dxCu(I,j))
     G%IdyCu(I,j) = Adcroft_reciprocal(G%dyCu(I,j))
+    G%IdxCu_OBCmask(I,j) = G%OBCmaskCu(I,j) * G%IdxCu(I,j) ! This may be reset when the masks are set.
   enddo ; enddo
 
   do J=JsdB,JedB ; do i=isd,ied
@@ -478,6 +494,7 @@ subroutine set_derived_dyn_horgrid(G, US)
     if (G%dyCv(i,J) < 0.0) G%dyCv(i,J) = 0.0
     G%IdxCv(i,J) = Adcroft_reciprocal(G%dxCv(i,J))
     G%IdyCv(i,J) = Adcroft_reciprocal(G%dyCv(i,J))
+    G%IdyCv_OBCmask(i,J) = G%OBCmaskCv(i,J) * G%IdyCv(i,J) ! This may be reset when the masks are set.
   enddo ; enddo
 
   do J=JsdB,JedB ; do I=IsdB,IedB
@@ -495,7 +512,7 @@ end subroutine set_derived_dyn_horgrid
 
 !> Adcroft_reciprocal(x) = 1/x for |x|>0 or 0 for x=0.
 function Adcroft_reciprocal(val) result(I_val)
-  real, intent(in) :: val  !< The value being inverted in abitrary units [A ~> a]
+  real, intent(in) :: val  !< The value being inverted in arbitrary units [A ~> a]
   real :: I_val            !< The Adcroft reciprocal of val [A-1 ~> a-1].
 
   I_val = 0.0 ; if (val /= 0.0) I_val = 1.0/val
@@ -519,10 +536,11 @@ subroutine destroy_dyn_horgrid(G)
   deallocate(G%areaT)  ; deallocate(G%IareaT)
   deallocate(G%areaBu) ; deallocate(G%IareaBu)
   deallocate(G%areaCu) ; deallocate(G%IareaCu)
-  deallocate(G%areaCv)  ; deallocate(G%IareaCv)
+  deallocate(G%areaCv) ; deallocate(G%IareaCv)
 
   deallocate(G%mask2dT)  ; deallocate(G%mask2dCu) ; deallocate(G%OBCmaskCu)
   deallocate(G%mask2dCv) ; deallocate(G%OBCmaskCv) ; deallocate(G%mask2dBu)
+  deallocate(G%IdxCu_OBCmask) ; deallocate(G%IdyCv_OBCmask)
 
   deallocate(G%geoLatT)  ; deallocate(G%geoLatCu)
   deallocate(G%geoLatCv) ; deallocate(G%geoLatBu)
@@ -534,9 +552,10 @@ subroutine destroy_dyn_horgrid(G)
   deallocate(G%porous_DminU) ; deallocate(G%porous_DmaxU) ; deallocate(G%porous_DavgU)
   deallocate(G%porous_DminV) ; deallocate(G%porous_DmaxV) ; deallocate(G%porous_DavgV)
 
-  deallocate(G%bathyT)  ; deallocate(G%CoriolisBu) ; deallocate(G%Coriolis2Bu)
-  deallocate(G%dF_dx)   ; deallocate(G%dF_dy)
-  deallocate(G%sin_rot) ; deallocate(G%cos_rot)
+  deallocate(G%bathyT)     ; deallocate(G%meanSL)
+  deallocate(G%CoriolisBu) ; deallocate(G%Coriolis2Bu)
+  deallocate(G%dF_dx)      ; deallocate(G%dF_dy)
+  deallocate(G%sin_rot)    ; deallocate(G%cos_rot)
 
   if (allocated(G%Dblock_u)) deallocate(G%Dblock_u)
   if (allocated(G%Dopen_u)) deallocate(G%Dopen_u)
diff --git a/src/framework/MOM_horizontal_regridding.F90 b/src/framework/MOM_horizontal_regridding.F90
index 3b296e8b65..64a1fadff2 100644
--- a/src/framework/MOM_horizontal_regridding.F90
+++ b/src/framework/MOM_horizontal_regridding.F90
@@ -16,7 +16,7 @@ module MOM_horizontal_regridding
 use MOM_interpolate,   only : time_interp_external
 use MOM_interp_infra,  only : run_horiz_interp, build_horiz_interp_weights
 use MOM_interp_infra,  only : horiz_interp_type, horizontal_interp_init
-use MOM_interp_infra,  only : get_external_field_info
+use MOM_interpolate,   only : get_external_field_info
 use MOM_interp_infra,  only : external_field
 use MOM_time_manager,  only : time_type
 use MOM_io,            only : axis_info, get_axis_info, get_var_axes_info, MOM_read_data
diff --git a/src/framework/MOM_interpolate.F90 b/src/framework/MOM_interpolate.F90
index 5a830fb028..d6ce5c720f 100644
--- a/src/framework/MOM_interpolate.F90
+++ b/src/framework/MOM_interpolate.F90
@@ -7,9 +7,13 @@ module MOM_interpolate
 use MOM_error_handler,   only : MOM_error, FATAL
 use MOM_interp_infra,    only : time_interp_extern, init_external_field=>init_extern_field
 use MOM_interp_infra,    only : time_interp_external_init=>time_interp_extern_init
-use MOM_interp_infra,    only : horiz_interp_type, get_external_field_info
+use MOM_interp_infra,    only : horiz_interp_type
+use MOM_interp_infra,    only : get_external_field_info_infra => get_external_field_info
 use MOM_interp_infra,    only : run_horiz_interp, build_horiz_interp_weights
 use MOM_interp_infra,    only : external_field
+use MOM_io_infra,        only : axistype
+use MOM_io_infra,        only : get_axis_size, get_axis_data
+use MOM_io,              only : axis_info, set_axis_info
 use MOM_time_manager, only : time_type, set_date, operator(+), operator(<), operator(>)
 
 implicit none ; private
@@ -26,7 +30,8 @@ module MOM_interpolate
     type(time_type) :: m2d_offset    !< add to model time to get data time
 end type forcing_timeseries_dataset
 
-public :: time_interp_external, init_external_field, time_interp_external_init, get_external_field_info
+public :: time_interp_external, init_external_field, time_interp_external_init
+public :: get_external_field_info
 public :: horiz_interp_type, run_horiz_interp, build_horiz_interp_weights
 public :: external_field
 public :: forcing_timeseries_set_time_type_vars
@@ -277,4 +282,46 @@ function map_model_time_to_forcing_time(Time, forcing_dataset)
 
 end function map_model_time_to_forcing_time
 
+
+subroutine get_external_field_info(field, size, axes, missing)
+  type(external_field), intent(in) :: field
+    !< Handle for time interpolated external field returned from a previous
+    !! call to init_external_field()
+  integer, optional, intent(inout) :: size(4)
+    !< Dimension sizes for the input data
+  type(axis_info), optional, intent(inout) :: axes(4)
+    !< Axis types for the input data
+  real, optional, intent(inout) :: missing
+    !< Missing value for the input data
+
+  type(axistype) :: axes_infra(4)
+    ! Axis as represented in the infra
+  character(len=256) :: axis_name
+    ! Axis name
+  real, allocatable :: ax_data(:)
+    ! Axis points
+
+  integer :: n
+    ! Axis index
+  integer :: ax_size
+    ! Axis size
+
+  if (present(axes)) then
+    call get_external_field_info_infra(field, size=size, axes=axes_infra, &
+        missing=missing)
+    ! TODO: Most of these methods were written to expect four dimensions.
+    do n=1,4
+      ! Convert axistype to axis_info
+      ax_size = get_axis_size(axes_infra(n))
+      allocate(ax_data(ax_size))
+      call get_axis_data(axes_infra(n), axis_name, ax_data)
+      call set_axis_info(axes(n), trim(axis_name), ax_data=ax_data)
+      deallocate(ax_data)
+    enddo
+  else
+    call get_external_field_info_infra(field, size=size, missing=missing)
+  endif
+end subroutine get_external_field_info
+
+
 end module MOM_interpolate
diff --git a/src/framework/MOM_intrinsic_functions.F90 b/src/framework/MOM_intrinsic_functions.F90
index fdafa8503d..5724e330c6 100644
--- a/src/framework/MOM_intrinsic_functions.F90
+++ b/src/framework/MOM_intrinsic_functions.F90
@@ -117,7 +117,7 @@ end function cuberoot
 !> Rescale `a` to the range [0.125, 1) and compute its cube-root exponent.
 pure subroutine rescale_cbrt(a, x, e_r, s_a)
   real, intent(in) :: a
-    !< The real parameter to be rescaled for cube root in abitrary units cubed [A3]
+    !< The real parameter to be rescaled for cube root in arbitrary units cubed [A3]
   real, intent(out) :: x
     !< The rescaled value of a in the range from 0.125 < asx <= 1.0, in ambiguous units cubed [B3]
   integer(kind=int64), intent(out) :: e_r
@@ -168,7 +168,7 @@ pure function descale(x, e_a, s_a) result(a)
   integer(kind=int64), intent(in) :: s_a
     !< Sign bit of the unscaled value
   real :: a
-    !< Restored value with the corrected exponent and sign in abitrary units [A]
+    !< Restored value with the corrected exponent and sign in arbitrary units [A]
 
   integer(kind=int64) :: xb
     ! Bit-packed real number into integer form
diff --git a/src/framework/MOM_netcdf.F90 b/src/framework/MOM_netcdf.F90
index 4a7a61ec1c..122d2797ba 100644
--- a/src/framework/MOM_netcdf.F90
+++ b/src/framework/MOM_netcdf.F90
@@ -799,7 +799,7 @@ subroutine check_netcdf_call(ncerr, header, message)
   character(len=:), allocatable :: errmsg
     ! Full error message, including netCDF message
 
-  if (ncerr /= nf90_noerr) then
+  if (ncerr /= NF90_NOERR) then
     errmsg = trim(header) // ": " // trim(message) // new_line('/') &
       // trim(nf90_strerror(ncerr))
     call MOM_error(FATAL, errmsg)
diff --git a/src/framework/MOM_string_functions.F90 b/src/framework/MOM_string_functions.F90
index cabe0f6e40..ab7b8b8bd7 100644
--- a/src/framework/MOM_string_functions.F90
+++ b/src/framework/MOM_string_functions.F90
@@ -17,6 +17,8 @@ module MOM_string_functions
 public extract_real
 public remove_spaces
 public slasher
+public trim_trailing_commas
+public ints_to_string
 
 contains
 
@@ -326,6 +328,10 @@ logical function string_functions_unit_tests(verbose)
   fail = fail .or. localTestS(v,left_reals(r(:)),'0.0, 1.0, -2.0, 1.3, 3*3.0E-11, -5.1E+12')
   fail = fail .or. localTestS(v,left_reals(r(:),sep=' '),'0.0 1.0 -2.0 1.3 3*3.0E-11 -5.1E+12')
   fail = fail .or. localTestS(v,left_reals(r(:),sep=','),'0.0,1.0,-2.0,1.3,3*3.0E-11,-5.1E+12')
+  fail = fail .or. localTestS(v,ints_to_string(i(:),5),'_-0001_0001_0003_0003_0000')
+  fail = fail .or. localTestS(v,ints_to_string(i(2:),2),'_0001_0003')
+  fail = fail .or. localTestS(v,ints_to_string(i(:)),'_-0001_0001_0003')
+  fail = fail .or. localTestS(v,trim_trailing_commas("One, Two, Three, "), "One, Two, Three")
   fail = fail .or. localTestS(v,extractWord("One Two,Three",1),"One")
   fail = fail .or. localTestS(v,extractWord("One Two,Three",2),"Two")
   fail = fail .or. localTestS(v,extractWord("One Two,Three",3),"Three")
@@ -417,6 +423,49 @@ function slasher(dir)
   endif
 end function slasher
 
+!> Returns a left-adjusted string with trailing blanks and commas removed.
+function trim_trailing_commas(in_str) result(out_str)
+  character(len=*), intent(in) :: in_str  !< A string that is to be left adjusted and have
+                                          !! its trailing commas and white space removed.
+  character(len=len(in_str))   :: out_str !< A left-adjusted version of in_str with
+                                          !! trailing commas and white space removed
+
+  out_str = trim(adjustl(in_str))
+  if (len_trim(out_str) > 0) then
+    if (out_str(len_trim(out_str):len_trim(out_str)) == ",") then
+      out_str = out_str(1:len_trim(out_str) - 1)
+    endif
+    out_str = trim(out_str)
+  endif
+
+end function trim_trailing_commas
+
+!> Convert the first n elements (3 by default) of an integer array into an underscore delimited string.
+function ints_to_string(a, n) result(i2s)
+  integer, dimension(:), intent(in) :: a !< The array of integers to translate
+  integer, optional    , intent(in) :: n !< The number of elements to translate, by default the lesser
+                                         !! of 3 or all of the integers
+  character(len=5*size(a)+1) :: i2s !< The returned underscore delimited string of integers
+
+  character(len=8) :: i2s_temp
+  integer :: i, n_max
+
+  n_max = 3
+  if (present(n)) n_max = n
+
+  i2s = ''
+  do i=1,min(size(a), n_max)
+    if (a(i) < 0) then
+      write (i2s_temp, '(I5.4)') a(i)
+    else
+      write (i2s_temp, '(I4.4)') a(i)
+    endif
+    i2s = trim(i2s) //'_'// trim(i2s_temp)
+  enddo
+  i2s = adjustl(i2s)
+end function ints_to_string
+
+
 !> \namespace mom_string_functions
 !!
 !!  By Alistair Adcroft and Robert Hallberg, last updated Sept. 2013.
diff --git a/src/ice_shelf/MOM_ice_shelf.F90 b/src/ice_shelf/MOM_ice_shelf.F90
index 2def8097ea..dde79f8855 100644
--- a/src/ice_shelf/MOM_ice_shelf.F90
+++ b/src/ice_shelf/MOM_ice_shelf.F90
@@ -126,9 +126,9 @@ module MOM_ice_shelf
   real :: kd_molec_salt!< The molecular diffusivity of salt [Z2 T-1 ~> m2 s-1].
   real :: kd_molec_temp!< The molecular diffusivity of heat [Z2 T-1 ~> m2 s-1].
   real :: Lat_fusion   !< The latent heat of fusion [Q ~> J kg-1].
-  real :: Gamma_T_3EQ  !<  Nondimensional heat-transfer coefficient, used in the 3Eq. formulation
-  real :: Gamma_S_3EQ  !<  Nondimensional salt-transfer coefficient, used in the 3Eq. formulation
-                       !<  This number should be specified by the user.
+  real :: Gamma_T_3EQ  !< Nondimensional heat-transfer coefficient, used in the 3Eq. formulation [nondim]
+  real :: Gamma_S_3EQ  !< Nondimensional salt-transfer coefficient, used in the 3Eq. formulation [nondim]
+                       !< This number should be specified by the user.
   real :: col_mass_melt_threshold !< An ocean column mass below the iceshelf below which melting
                        !! does not occur [R Z ~> kg m-2]
   logical :: mass_from_file !< Read the ice shelf mass from a file every dt
@@ -194,12 +194,13 @@ module MOM_ice_shelf
   real    :: dTFr_dp                     !< Partial derivative of freezing temperature with
                                          !! pressure [C T2 R-1 L-2 ~> degC Pa-1]
   real    :: Zeta_N                      !< The stability constant xi_N = 0.052 from Holland & Jenkins '99
-                                         !! divided by the von Karman constant VK. Was 1/8.
-  real :: Vk                             !< Von Karman's constant - dimensionless
-  real :: Rc                             !< critical flux Richardson number.
-  logical :: buoy_flux_itt_bug           !< If true, fixes buoyancy iteration bug
-  logical :: salt_flux_itt_bug           !< If true, fixes salt iteration bug
-  real :: buoy_flux_itt_threshold        !< Buoyancy iteration threshold for convergence
+                                         !! divided by the von Karman constant VK [nondim]. Was 1/8.
+  real :: Vk                             !< Von Karman's constant [nondim]
+  real :: Rc                             !< critical flux Richardson number [nondim]
+  logical :: ustar_from_vel_bugfix       !< If true, fixes ustar from ocean velocity bug
+  logical :: buoy_flux_itt_bugfix        !< If true, fixes buoyancy iteration bug
+  logical :: salt_flux_itt_bugfix        !< If true, fixes salt iteration bug
+  real :: buoy_flux_tol                  !< Fractional buoyancy iteration tolerance for convergence [nondim]
 
   !>@{ Diagnostic handles
   integer :: id_melt = -1, id_exch_vel_s = -1, id_exch_vel_t = -1, &
@@ -294,12 +295,13 @@ subroutine shelf_calc_flux(sfc_state_in, fluxes_in, Time, time_step_in, CS)
                !! This is computed as part of the ISOMIP diagnostics.
   real :: time_step !< Length of time over which these fluxes will be applied [T ~> s].
   real :: Itime_step !< Inverse of the length of time over which these fluxes will be applied [T-1 ~> s-1]
-  real :: VK       !< Von Karman's constant - dimensionless
+  real :: VK       !< Von Karman's constant [nondim]
   real :: ZETA_N   !< This is the stability constant xi_N = 0.052 from Holland & Jenkins '99
                    !! divided by the von Karman constant VK. Was 1/8. [nondim]
-  real :: RC       !< critical flux Richardson number.
-  real :: I_ZETA_N !< The inverse of ZETA_N [nondim].
+  real :: Rf_crit  !< critical flux Richardson number  [nondim]
+  real :: I_2Zeta_N !< Half the inverse of Zeta_N [nondim].
   real :: I_LF     !< The inverse of the latent heat of fusion [Q-1 ~> kg J-1].
+  real :: I_dt_LHF  ! The inverse of the timestep times the latent heat of fusion [Q-1 T-1 ~> kg J-1 s-1].
   real :: I_VK     !< The inverse of the Von Karman constant [nondim].
   real :: PR, SC   !< The Prandtl number and Schmidt number [nondim].
 
@@ -318,7 +320,8 @@ subroutine shelf_calc_flux(sfc_state_in, fluxes_in, Time, time_step_in, CS)
   real :: wB_flux !< The downward vertical flux of buoyancy just inside the ocean [Z2 T-3 ~> m2 s-3].
   real :: dB_dS   !< The derivative of buoyancy with salinity [Z T-2 S-1 ~> m s-2 ppt-1].
   real :: dB_dT   !< The derivative of buoyancy with temperature [Z T-2 C-1 ~> m s-2 degC-1].
-  real :: I_n_star ! [nondim]
+  real :: I_n_star ! The inverse of the ratio of working boundary layer thickness
+                   ! to the neutral thickness [nondim]
   real :: n_star_term ! A term in the expression for nstar [T3 Z-2 ~> s3 m-2]
   real :: absf     ! The absolute value of the Coriolis parameter [T-1 ~> s-1]
   real :: dIns_dwB !< The partial derivative of I_n_star with wB_flux, in [T3 Z-2 ~> s3 m-2]
@@ -327,34 +330,42 @@ subroutine shelf_calc_flux(sfc_state_in, fluxes_in, Time, time_step_in, CS)
   real :: dS_ustar ! The difference between the salinity at the ice-ocean interface and the ocean
                    ! boundary layer salinity times the friction velocity [S Z T-1 ~> ppt m s-1]
   real :: ustar_h  ! The friction velocity in the water below the ice shelf [Z T-1 ~> m s-1]
-  real :: Gam_turb ! [nondim]
+  real :: Gam_turb ! A relative turbluent diffusivity [nondim]
   real :: Gam_mol_t, Gam_mol_s ! Relative coefficients of molecular diffusivities [nondim]
   real :: RhoCp     ! A typical ocean density times the heat capacity of water [Q R C-1 ~> J m-3 degC-1]
-  real :: ln_neut
+  real :: ln_neut   ! The log of the ratio of the neutral boundary layer thickness to the molecular
+                    ! boundary layer thickness if it is greater than 1 or 0 otherwise [nondim]
   real :: mass_exch ! A mass exchange rate [R Z T-1 ~> kg m-2 s-1]
   real :: Sb_min, Sb_max ! Minimum and maximum boundary salinities [S ~> ppt]
   real :: dS_min, dS_max ! Minimum and maximum salinity changes [S ~> ppt]
   ! Variables used in iterating for wB_flux.
-  real :: wB_flux_new, dDwB_dwB_in
-  real :: I_Gam_T, I_Gam_S
-  real :: dG_dwB   ! The derivative of Gam_turb with wB [T3 Z-2 ~> s3 m-2]
+  real :: wB_flux_next ! The next interation's guess for wB_flux [Z2 T-3 ~> m2 s-3]
+  real :: wB_flux_new  ! An updated value of wB_flux when Gam_turb is based on wB_flux [Z2 T-3 ~> m2 s-3]
+  real :: wB_flux_max  ! The upper bound on wB_flux [Z2 T-3 ~> m2 s-3]
+  real :: wB_flux_min  ! The lower bound on wB_flux [Z2 T-3 ~> m2 s-3]
+  real :: dDwB_dwB     ! The slope of the change in wB_flux between iterations with wB_flux [nondim]
+  real :: DwB_max      ! The change in wB_flux when it is wB_flux_max [Z2 T-3 ~> m2 s-3]
+  real :: DwB_min      ! The change in wB_flux when it is wB_flux_min [Z2 T-3 ~> m2 s-3]
+  real :: I_Gam_T, I_Gam_S  ! Terms that vary inversely with Gam_mol_T or Gam_mol_S and Gam_turb [nondim]
+  real :: dG_dwB       ! The derivative of Gam_turb with wB [T3 Z-2 ~> s3 m-2]
   real :: taux2, tauy2 ! The squared surface stresses [R2 L2 Z2 T-4 ~> Pa2].
   real :: u2_av, v2_av ! The ice-area weighted average squared ocean velocities [L2 T-2 ~> m2 s-2]
-  real :: asu1, asu2   ! Ocean areas covered by ice shelves at neighboring u-
-  real :: asv1, asv2   ! and v-points [L2 ~> m2].
+  real :: asu1, asu2   ! Ocean areas covered by ice shelves at neighboring u-points [L2 ~> m2]
+  real :: asv1, asv2   ! Ocean areas covered by ice shelves at neighboring v-points [L2 ~> m2]
   real :: I_au, I_av   ! The Adcroft reciprocals of the ice shelf areas at adjacent points [L-2 ~> m-2]
   real :: Irho0        ! The inverse of the mean density times a unit conversion factor [R-1 L Z-1 ~> m3 kg-1]
   logical :: Sb_min_set, Sb_max_set
+  logical :: root_found
   logical :: update_ice_vel ! If true, it is time to update the ice shelf velocities.
   logical :: coupled_GL     ! If true, the grounding line position is determined based on
                             ! coupled ice-ocean dynamics.
-
-  real, parameter :: c2_3 = 2.0/3.0
-  character(len=160) :: mesg  ! The text of an error message
+  logical :: add_frazil ! If true, allow frazil formation to modify ice-shelf water flux
+  real, parameter :: c2_3 = 2.0/3.0 ! Two thirds [nondim]
+  character(len=320) :: mesg  ! The text of an error message
   integer, dimension(2) :: EOSdom ! The i-computational domain for the equation of state
   integer :: i, j, is, ie, js, je, ied, jed, it1, it3
-  real :: vaf0, vaf0_A, vaf0_G !The previous volumes above floatation [Z L2 ~> m3]
-                               !for all ice sheets, Antarctica only, or Greenland only [Z L2 ~> m3]
+  real :: vaf0, vaf0_A, vaf0_G ! The previous volumes above floatation [Z L2 ~> m3]
+                               ! for all ice sheets, Antarctica only, or Greenland only
 
   if (.not. associated(CS)) call MOM_error(FATAL, "shelf_calc_flux: "// &
        "initialize_ice_shelf must be called before shelf_calc_flux.")
@@ -394,9 +405,10 @@ subroutine shelf_calc_flux(sfc_state_in, fluxes_in, Time, time_step_in, CS)
   ! useful parameters
   ZETA_N = CS%Zeta_N
   VK = CS%Vk
-  RC = CS%Rc
-  I_ZETA_N = 1.0 / ZETA_N
+  Rf_crit = CS%Rc
+  I_2Zeta_N = 0.5 / CS%Zeta_N
   I_LF = 1.0 / CS%Lat_fusion
+  I_dt_LHF = 1.0 / (time_step * CS%Lat_fusion)
   SC = CS%kv_molec/CS%kd_molec_salt
   PR = CS%kv_molec/CS%kd_molec_temp
   I_VK = 1.0/VK
@@ -454,7 +466,11 @@ subroutine shelf_calc_flux(sfc_state_in, fluxes_in, Time, time_step_in, CS)
       tauy2 = (((asv1 * (sfc_state%tauy_shelf(i,J-1)**2)) + (asv2 * (sfc_state%tauy_shelf(i,J)**2))  ) * I_av)
     endif
     u2_av = (((asu1 * (sfc_state%u(I-1,j)**2)) + (asu2 * sfc_state%u(I,j)**2)) * I_au)
-    v2_av = (((asv1 * (sfc_state%v(i,J-1)**2)) + (asu2 * sfc_state%v(i,J)**2)) * I_av)
+    if (CS%ustar_from_vel_bugfix) then
+      v2_av = (((asv1 * (sfc_state%v(i,J-1)**2)) + (asv2 * sfc_state%v(i,J)**2)) * I_av)
+    else
+      v2_av = (((asv1 * (sfc_state%v(i,J-1)**2)) + (asu2 * sfc_state%v(i,J)**2)) * I_av)
+    endif
 
     if ((taux2 + tauy2 > 0.0) .and. .not.CS%ustar_shelf_from_vel) then
       if (CS%ustar_max >= 0.0) then
@@ -486,7 +502,8 @@ subroutine shelf_calc_flux(sfc_state_in, fluxes_in, Time, time_step_in, CS)
 
     do i=is,ie
       if ((sfc_state%ocean_mass(i,j) > CS%col_mass_melt_threshold) .and. &
-          (ISS%area_shelf_h(i,j) > 0.0) .and. CS%isthermo) then
+          (ISS%area_shelf_h(i,j) > 0.0) .and. CS%isthermo &
+           .and. ISS%melt_mask(i,j)>0.0) then
 
         if (CS%threeeq) then
           !   Iteratively determine a self-consistent set of fluxes, with the ocean
@@ -502,11 +519,12 @@ subroutine shelf_calc_flux(sfc_state_in, fluxes_in, Time, time_step_in, CS)
           if (absf*sfc_state%Hml(i,j) <= VK*ustar_h) then ; hBL_neut = sfc_state%Hml(i,j)
           else ; hBL_neut = (VK*ustar_h) / absf ; endif
           hBL_neut_h_molec = ZETA_N * ((hBL_neut * ustar_h) / (5.0 * CS%kv_molec))
+          ln_neut = 0.0 ; if (hBL_neut_h_molec > 1.0) ln_neut = log(hBL_neut_h_molec)
+          n_star_term = (ZETA_N * hBL_neut * VK) / (Rf_crit * ustar_h**3)
 
           ! Determine the mixed layer buoyancy flux, wB_flux.
           dB_dS = (US%L_to_Z**2*CS%g_Earth / Rhoml(i)) * dR0_dS(i)
           dB_dT = (US%L_to_Z**2*CS%g_Earth / Rhoml(i)) * dR0_dT(i)
-          ln_neut = 0.0 ; if (hBL_neut_h_molec > 1.0) ln_neut = log(hBL_neut_h_molec)
 
           if (CS%find_salt_root) then
             ! Solve for the skin salinity using the linearized liquidus parameters and
@@ -556,68 +574,152 @@ subroutine shelf_calc_flux(sfc_state_in, fluxes_in, Time, time_step_in, CS)
             dT_ustar = (ISS%tfreeze(i,j) - sfc_state%sst(i,j)) * ustar_h
             dS_ustar = (Sbdry(i,j) - sfc_state%sss(i,j)) * ustar_h
 
-            ! First, determine the buoyancy flux assuming no effects of stability
-            ! on the turbulence.  Following H & J '99, this limit also applies
-            ! when the buoyancy flux is destabilizing.
-
-            if (CS%const_gamma) then ! if using a constant gamma_T
-              ! note the different form, here I_Gam_T is NOT 1/Gam_T!
+            if (CS%const_gamma) then
+              ! If using a constant gamma_T, there are no effects of the buoyancy flux on the turbulence.
               I_Gam_T = CS%Gamma_T_3EQ
               I_Gam_S = CS%Gamma_S_3EQ
-            else
-              Gam_turb = I_VK * (ln_neut + (0.5 * I_ZETA_N - 1.0))
+              wT_flux = dT_ustar * CS%Gamma_T_3EQ
+              wB_flux = dB_dS * (dS_ustar * CS%Gamma_S_3EQ) + dB_dT * wT_flux
+            elseif (.not.CS%buoy_flux_itt_bugfix) then
+              ! Gamma_T and gamma_S are a function of the buoyancy flux, and there should have been
+              ! iteration to find the root where wB_flux is consistent with the values of gamma with
+              ! that flux, but it was omitted.
+              Gam_turb = I_VK * (ln_neut + (I_2Zeta_N - 1.0))
               I_Gam_T = 1.0 / (Gam_mol_t + Gam_turb)
               I_Gam_S = 1.0 / (Gam_mol_s + Gam_turb)
-            endif
+              wB_flux = dB_dS * (dS_ustar * I_Gam_S) + dB_dT * (dT_ustar * I_Gam_T)
 
-            wT_flux = dT_ustar * I_Gam_T
-            wB_flux = dB_dS * (dS_ustar * I_Gam_S) + dB_dT * wT_flux
+              if (wB_flux < 0.0) then  ! The stabilising buoyancy flux reduces the turbulent fluxes.
+                I_n_star = sqrt(1.0 - n_star_term * wB_flux)
+                if (hBL_neut_h_molec > I_n_star**2) then
+                  Gam_turb = I_VK * ((ln_neut - 2.0*log(I_n_star)) + (I_2Zeta_N*I_n_star - 1.0))
+                else ! The layer dominated by molecular viscosity is smaller than the boundary layer.
+                  Gam_turb = I_VK * (I_2Zeta_N*I_n_star - 1.0)
+                endif
+                I_Gam_T = 1.0 / (Gam_mol_t + Gam_turb)
+                I_Gam_S = 1.0 / (Gam_mol_s + Gam_turb)
+              endif
+              wT_flux = dT_ustar * I_Gam_T
+            else  ! gamma_T and gamma_S are a function of the buoyancy flux with proper iteration.
+              ! Find the root where wB_flux is consistent with the values of gamma with that flux.
+
+              ! First, determine the buoyancy flux assuming no effects of stability
+              ! on the turbulence.  Following H & J '99, this limit also applies
+              ! when the buoyancy flux is destabilizing.
+              Gam_turb = I_VK * (ln_neut + (I_2Zeta_N - 1.0))
+              I_Gam_T = 1.0 / (Gam_mol_t + Gam_turb)
+              I_Gam_S = 1.0 / (Gam_mol_s + Gam_turb)
+              wB_flux = (dB_dS * dS_ustar) * I_Gam_S + (dB_dT * dT_ustar) * I_Gam_T
 
-            if (wB_flux < 0.0) then
-              ! The buoyancy flux is stabilizing and will reduce the turbulent
-              ! fluxes, and iteration is required.
-              n_star_term = (ZETA_N * hBL_neut * VK) / (RC * ustar_h**3)
-              do it3 = 1,30
-               ! n_star <= 1.0 is the ratio of working boundary layer thickness
-               ! to the neutral thickness.
-               ! hBL = n_star*hBL_neut ; hSub = 1/8*n_star*hBL
+              if (wB_flux < 0.0) then
+                ! The buoyancy flux is stabilizing and will reduce the turbulent
+                ! fluxes, and iteration is required.
 
+                ! n_star <= 1.0 is the ratio of working boundary layer thickness
+                ! to the neutral thickness.  I_n_star is its inverse.
                 I_n_star = sqrt(1.0 - n_star_term * wB_flux)
-                dIns_dwB = 0.5 * n_star_term / I_n_star
                 if (hBL_neut_h_molec > I_n_star**2) then
-                  Gam_turb = I_VK * ((ln_neut - 2.0*log(I_n_star)) + &
-                                    (0.5*I_ZETA_N*I_n_star - 1.0))
-                  dG_dwB =  I_VK * ( -2.0 / I_n_star + (0.5 * I_ZETA_N)) * dIns_dwB
-                else
-                  !   The layer dominated by molecular viscosity is smaller than
-                  ! the assumed boundary layer.  This should be rare!
-                  Gam_turb = I_VK * (0.5 * I_ZETA_N*I_n_star - 1.0)
-                  dG_dwB = I_VK * (0.5 * I_ZETA_N) * dIns_dwB
+                  Gam_turb = I_VK * ((ln_neut - 2.0*log(I_n_star)) + (I_2Zeta_N*I_n_star - 1.0))
+                else !   The layer dominated by molecular viscosity is smaller than the boundary layer.
+                  Gam_turb = I_VK * (I_2Zeta_N*I_n_star - 1.0)
                 endif
-
-                if (CS%const_gamma) then ! if using a constant gamma_T
-                  ! note the different form, here I_Gam_T is NOT 1/Gam_T!
-                  I_Gam_T = CS%Gamma_T_3EQ
-                  I_Gam_S = CS%Gamma_S_3EQ
-                else
-                  I_Gam_T = 1.0 / (Gam_mol_t + Gam_turb)
-                  I_Gam_S = 1.0 / (Gam_mol_s + Gam_turb)
+                I_Gam_T = 1.0 / (Gam_mol_t + Gam_turb)
+                I_Gam_S = 1.0 / (Gam_mol_s + Gam_turb)
+
+                wB_flux_new = (dB_dS * dS_ustar) * I_Gam_S + (dB_dT * dT_ustar) * I_Gam_T
+                root_found = (abs(wB_flux_new - wB_flux) < CS%buoy_flux_tol*(abs(wB_flux_new) + abs(wB_flux)))
+                ! Do not update the flux if its maagnitude would be increased by the otherwise
+                ! stabilizing buoyancy fluxes.  This can happen when the buoyancy flux
+                ! is stabilizing when one of the heat or salt fluxes are destabilizing due
+                ! to their different molecular properties.
+                if (wB_flux_new <= wB_flux) root_found = .true.
+
+                if (.not.root_found) then
+                  wB_flux_max = 0.0 ; DwB_max = wB_flux
+                  wB_flux_min = wB_flux ; DwB_min = wB_flux_new - wB_flux
+
+                  if ((wB_flux_min*n_star_term < (1.0 - hBL_neut_h_molec)) .and. &
+                      ((1.0 - hBL_neut_h_molec) < wB_flux_max*n_star_term)) then
+                    ! The derivative of Gam_turb with wB_flux has a discontinuous change within the
+                    ! bracketed range of values.  Take this discontinous slope value for a first
+                    ! guess, because Newton's method and the false position method may not converge
+                    ! quickly when this discontinuity is between a guess and the solution.
+                    wB_flux = (1.0 - hBL_neut_h_molec) / n_star_term
+                    I_n_star = sqrt(hBL_neut_h_molec)
+                    Gam_turb = I_VK * (I_2Zeta_N*I_n_star - 1.0)
+                    I_Gam_T = 1.0 / (Gam_mol_t + Gam_turb)
+                    I_Gam_S = 1.0 / (Gam_mol_s + Gam_turb)
+                    wB_flux_new = (dB_dS * dS_ustar) * I_Gam_S + (dB_dT * dT_ustar) * I_Gam_T
+
+                    if (abs(wB_flux_new - wB_flux) <= CS%buoy_flux_tol*(abs(wB_flux_new) + abs(wB_flux))) then
+                      ! The root has been found to within the tolerance at the kink.  This should be very rare.
+                      root_found = .true.
+                    elseif (wB_flux_new > wB_flux) then
+                      ! The solution is in the limit where abs(wB_flux) is small and
+                      ! Gam_turb = I_VK * ((ln_neut - 2.0*log(I_n_star)) + (I_2Zeta_N*I_n_star - 1.0))
+                      wB_flux_min = wB_flux ; DwB_min = wB_flux_new - wB_flux
+                    else
+                      ! The solution is in the limt where abs(wB_flux) is large and
+                      ! Gam_turb = I_VK * (I_2Zeta_N*I_n_star - 1.0)
+                      wB_flux_max = wB_flux ; DwB_max = wB_flux_new - wB_flux
+                    endif
+                  endif
                 endif
 
-                wT_flux = dT_ustar * I_Gam_T
-                wB_flux_new = dB_dS * (dS_ustar * I_Gam_S) + dB_dT * wT_flux
-
-                ! Find the root where wB_flux_new = wB_flux.
-                if (abs(wB_flux_new - wB_flux) < CS%buoy_flux_itt_threshold*(abs(wB_flux_new) + abs(wB_flux))) exit
+                if (.not.root_found) then
+                  ! Use the false position for the next guess.
+                  wB_flux = wB_flux_min + (wB_flux_max-wB_flux_min) * (DwB_min / (DwB_min - DwB_max))
+
+                  do it3 = 1,30
+                  ! Iterate using Newton's method with bounds or the false position method to find the root.
+
+                    I_n_star = sqrt(1.0 - n_star_term * wB_flux)
+                    dIns_dwB = -0.5 * n_star_term / I_n_star
+                    if (hBL_neut_h_molec > I_n_star**2) then
+                      Gam_turb = I_VK * ((ln_neut - 2.0*log(I_n_star)) + (I_2Zeta_N*I_n_star - 1.0))
+                      dG_dwB =  I_VK * (( -2.0 / I_n_star + I_2Zeta_N) * dIns_dwB)
+                    else
+                      !   The layer dominated by molecular viscosity is smaller than the boundary layer.
+                      Gam_turb = I_VK * (I_2Zeta_N*I_n_star - 1.0)
+                      dG_dwB = I_VK * (I_2Zeta_N * dIns_dwB)
+                    endif
+                    I_Gam_T = 1.0 / (Gam_mol_t + Gam_turb)
+                    I_Gam_S = 1.0 / (Gam_mol_s + Gam_turb)
+                    wB_flux_new = (dB_dS * dS_ustar) * I_Gam_S + (dB_dT * dT_ustar) * I_Gam_T
+
+                    ! Test for convergence to within tolerance at the point where wB_flux_new = wB_flux.
+                    if (abs(wB_flux_new - wB_flux) <= CS%buoy_flux_tol*(abs(wB_flux_new) + abs(wB_flux))) &
+                      root_found = .true.
+                    if (root_found) exit
+
+                    dDwB_dwB = -dG_dwB * ((dB_dS * dS_ustar) * I_Gam_S**2 + &
+                                          (dB_dT * dT_ustar) * I_Gam_T**2) - 1.0
+                    if ((dDwB_dwB >= 0.0) .or. &
+                        ( wB_flux - wB_flux_new >= abs(dDwB_dwB)*(wB_flux_max - wB_flux)) .or. &
+                        ( wB_flux - wB_flux_new <= abs(dDwB_dwB)*(wB_flux_min - wB_flux)) ) then
+                      ! Use the False position method to determine the guess for the next iteration when
+                      ! Newton's method would go out of bounds
+                      wB_flux_next = wB_flux_min + (wB_flux_max-wB_flux_min) * (DwB_min / (DwB_min - DwB_max))
+                    else
+                      ! Use Newton's method for the next guess.
+                      wB_flux_next = wB_flux - (wB_flux_new - wB_flux) / dDwB_dwB
+                    endif
+
+                    ! Reset one of the bounds inward.
+                    if (wB_flux_new - wB_flux > 0) then
+                      wB_flux_min = wB_flux ; DwB_min = wB_flux_new - wB_flux
+                    else
+                      wB_flux_max = wB_flux ; DwB_max = wB_flux_new - wB_flux
+                    endif
+
+                    ! Update wB_flux
+                    wB_flux = wB_flux_next
+                  enddo ! it3
+                endif
 
-                dDwB_dwB_in = dG_dwB * (dB_dS * (dS_ustar * I_Gam_S**2) + &
-                                        dB_dT * (dT_ustar * I_Gam_T**2)) - 1.0
-                ! This is Newton's method without any bounds.  Should bounds be needed?
-                wB_flux_new = wB_flux - (wB_flux_new - wB_flux) / dDwB_dwB_in
-                ! Update wB_flux
-                if (CS%buoy_flux_itt_bug) wB_flux = wB_flux_new
-              enddo !it3
-            endif
+              endif  ! End of test for first guess of wB_flux < 0.
+              wT_flux = dT_ustar * I_Gam_T
+            endif  ! End of test for CS%const_gamma
 
             ISS%tflux_ocn(i,j)  = RhoCp * wT_flux
             exch_vel_t(i,j) = ustar_h * I_Gam_T
@@ -688,7 +790,7 @@ subroutine shelf_calc_flux(sfc_state_in, fluxes_in, Time, time_step_in, CS)
                 Sbdry(i,j) = Sbdry_it
               endif ! Sb_min_set
 
-              if (.not.CS%salt_flux_itt_bug) Sbdry(i,j) = Sbdry_it
+              if (.not.CS%salt_flux_itt_bugfix) Sbdry(i,j) = Sbdry_it
 
             endif ! CS%find_salt_root
 
@@ -720,10 +822,20 @@ subroutine shelf_calc_flux(sfc_state_in, fluxes_in, Time, time_step_in, CS)
     enddo ! i-loop
   enddo ! j-loop
 
+  if (allocated(sfc_state%frazil)) then
+    add_frazil = .true.
+  else
+    add_frazil = .false.
+  endif
 
   do j=js,je ; do i=is,ie
     ! ISS%water_flux = net liquid water into the ocean [R Z T-1 ~> kg m-2 s-1]
-    fluxes%iceshelf_melt(i,j) = ISS%water_flux(i,j) * CS%flux_factor
+    if (CS%flux_factor/=1.0) then
+      ISS%water_flux(i,j) = ISS%water_flux(i,j) * CS%flux_factor
+      ISS%tflux_ocn(i,j) = ISS%tflux_ocn(i,j) * CS%flux_factor
+      if (CS%threeeq .and. ISS%tflux_ocn(i,j) < 0.0 .and. (.not. CS%insulator)) &
+        ISS%tflux_shelf(i,j)=ISS%tflux_ocn(i,j) + CS%Lat_fusion * ISS%water_flux(i,j)
+    endif
 
     if ((sfc_state%ocean_mass(i,j) > CS%col_mass_melt_threshold) .and. &
         (ISS%area_shelf_h(i,j) > 0.0) .and.  (CS%isthermo)) then
@@ -732,7 +844,6 @@ subroutine shelf_calc_flux(sfc_state_in, fluxes_in, Time, time_step_in, CS)
       ! This is needed for the ISOMIP test case.
       if (ISS%mass_shelf(i,j) < CS%Rho_ocn*CS%cutoff_depth) then
         ISS%water_flux(i,j) = 0.0
-        fluxes%iceshelf_melt(i,j) = 0.0
       endif
       ! Compute haline driving, which is one of the diags. used in ISOMIP
       if (exch_vel_s(i,j)>0.) haline_driving(i,j) = (ISS%water_flux(i,j) * Sbdry(i,j)) / (CS%Rho_ocn * exch_vel_s(i,j))
@@ -740,7 +851,7 @@ subroutine shelf_calc_flux(sfc_state_in, fluxes_in, Time, time_step_in, CS)
       !!!!!!!!!!!!!!!!!!!!!!!!!!!!Safety checks !!!!!!!!!!!!!!!!!!!!!!!!!
       !1)Check if haline_driving computed above is consistent with
       ! haline_driving = sfc_state%sss - Sbdry
-      !if (fluxes%iceshelf_melt(i,j) /= 0.0) then
+      !if (ISS%water_flux(i,j) /= 0.0) then
       !   if (haline_driving(i,j) /= (sfc_state%sss(i,j) - Sbdry(i,j))) then
       !     write(mesg,*) 'at i,j=',i,j,' haline_driving, sss-Sbdry',US%S_to_ppt*haline_driving(i,j), &
       !                   US%S_to_ppt*(sfc_state%sss(i,j) - Sbdry(i,j))
@@ -751,8 +862,8 @@ subroutine shelf_calc_flux(sfc_state_in, fluxes_in, Time, time_step_in, CS)
 
       ! 2) check if |melt| > 0 when ustar_shelf = 0.
       ! this should never happen
-      if ((abs(fluxes%iceshelf_melt(i,j))>0.0) .and. (fluxes%ustar_shelf(i,j) == 0.0)) then
-        write(mesg,*) "|melt| = ",fluxes%iceshelf_melt(i,j)," > 0 and ustar_shelf = 0. at i,j", i, j
+      if ((abs(ISS%water_flux(i,j))>0.0) .and. (fluxes%ustar_shelf(i,j) == 0.0)) then
+        write(mesg,*) "|melt| = ",ISS%water_flux(i,j)," > 0 and ustar_shelf = 0. at i,j", i, j
         call MOM_error(FATAL, "shelf_calc_flux: "//trim(mesg))
       endif
        !!!!!!!!!!!!!!!!!!!!!!!!!!!!End of safety checks !!!!!!!!!!!!!!!!!!!
@@ -760,11 +871,15 @@ subroutine shelf_calc_flux(sfc_state_in, fluxes_in, Time, time_step_in, CS)
       ! This is grounded ice, that could be modified to melt if a geothermal heat flux were used.
       haline_driving(i,j) = 0.0
       ISS%water_flux(i,j) = 0.0
-      fluxes%iceshelf_melt(i,j) = 0.0
     endif ! area_shelf_h
 
     ! mass flux [R Z L2 T-1 ~> kg s-1], part of ISOMIP diags.
     mass_flux(i,j) = ISS%water_flux(i,j) * ISS%area_shelf_h(i,j)
+
+    !Add frazil formation
+    if (add_frazil .and. (ISS%hmask(i,j) == 1 .or. ISS%hmask(i,j) == 2)) &
+      ISS%water_flux(i,j) = ISS%water_flux(i,j) - sfc_state%frazil(i,j) * I_dt_LHF
+    fluxes%iceshelf_melt(i,j) = ISS%water_flux(i,j)
   enddo ; enddo ! i- and j-loops
 
   if (CS%active_shelf_dynamics .or. CS%override_shelf_movement) then
@@ -1138,7 +1253,7 @@ subroutine add_shelf_flux(G, US, CS, sfc_state, fluxes, time_step)
   type(ice_shelf_CS),    pointer       :: CS   !< This module's control structure.
   type(surface),         intent(inout) :: sfc_state !< Surface ocean state
   type(forcing),         intent(inout) :: fluxes  !< A structure of surface fluxes that may be used/updated.
-  real,                  intent(in)    :: time_step !< Time step over which fluxes are applied
+  real,                  intent(in)    :: time_step !< Time step over which fluxes are applied [T ~> s]
   ! local variables
   real :: frac_shelf       !< The fractional area covered by the ice shelf [nondim].
   real :: frac_open        !< The fractional area of the ocean that is not covered by the ice shelf [nondim].
@@ -1215,15 +1330,15 @@ subroutine add_shelf_flux(G, US, CS, sfc_state, fluxes, time_step)
     if (associated(fluxes%evap)) fluxes%evap(i,j) = frac_open * fluxes%evap(i,j)
     if (associated(fluxes%lprec)) then
       if (ISS%water_flux(i,j) > 0.0) then
-        fluxes%lprec(i,j) =  frac_shelf*ISS%water_flux(i,j)*CS%flux_factor + frac_open * fluxes%lprec(i,j)
+        fluxes%lprec(i,j) =  frac_shelf*ISS%water_flux(i,j) + frac_open * fluxes%lprec(i,j)
       else
         fluxes%lprec(i,j) = frac_open * fluxes%lprec(i,j)
-        fluxes%evap(i,j) = fluxes%evap(i,j) + frac_shelf*ISS%water_flux(i,j)*CS%flux_factor
+        fluxes%evap(i,j) = fluxes%evap(i,j) + frac_shelf*ISS%water_flux(i,j)
       endif
     endif
 
     if (associated(fluxes%sens)) &
-      fluxes%sens(i,j) = frac_shelf*ISS%tflux_ocn(i,j)*CS%flux_factor + frac_open * fluxes%sens(i,j)
+      fluxes%sens(i,j) = frac_shelf*ISS%tflux_ocn(i,j) + frac_open * fluxes%sens(i,j)
     ! The salt flux should be mostly from sea ice, so perhaps none should be intercepted and this should be changed.
     if (associated(fluxes%salt_flux)) &
       fluxes%salt_flux(i,j) = frac_shelf * ISS%salt_flux(i,j)*CS%flux_factor + frac_open * fluxes%salt_flux(i,j)
@@ -1377,10 +1492,12 @@ subroutine initialize_ice_shelf(param_file, ocn_grid, Time, CS, diag, Time_init,
   type(directories)  :: dirs
   type(dyn_horgrid_type), pointer :: dG => NULL()
   type(dyn_horgrid_type), pointer :: dG_in => NULL()
-  real :: meltrate_conversion ! The conversion factor to use for in the melt rate diagnostic.
+  real :: meltrate_conversion ! The conversion factor to use for in the melt rate diagnostic
+                              ! [T kg R-1 Z-1 m-2 s-1 ~> nondim]
   real :: dz_ocean_min_float ! The minimum ocean thickness above which the ice shelf is considered
                         ! to be floating when CONST_SEA_LEVEL = True [Z ~> m].
-  real :: cdrag, drag_bg_vel
+  real :: cdrag         ! The drag coefficient at the ice-ocean interface [nondim]
+  real :: drag_bg_vel   ! A background velocity used in the quadratic drag [Z T-1 ~> m s-1]
   logical :: new_sim, save_IC
   !This include declares and sets the variable "version".
 # include "version_variable.h"
@@ -1396,7 +1513,7 @@ subroutine initialize_ice_shelf(param_file, ocn_grid, Time, CS, diag, Time_init,
   real    :: utide  ! A tidal velocity [L T-1 ~> m s-1]
   real    :: col_thick_melt_thresh ! An ocean column thickness below which iceshelf melting
                                    ! does not occur [Z ~> m]
-  real, allocatable, dimension(:,:) :: tmp2d ! Temporary array for storing ice shelf input data
+  real, allocatable, dimension(:,:) :: tmp2d ! Temporary array for ice shelf input data [L T-1 ~> m s-1]
 
   type(surface), pointer :: sfc_state => NULL()
   type(vardesc) :: u_desc, v_desc
@@ -1686,11 +1803,14 @@ subroutine initialize_ice_shelf(param_file, ocn_grid, Time, CS, diag, Time_init,
   call get_param(param_file, mdl, "ICE_SHELF_RC", CS%Rc, &
                  "Critical flux Richardson number for ice melt ", &
                  units="nondim", default=0.20)
-  call get_param(param_file, mdl, "ICE_SHELF_BUOYANCY_FLUX_ITT_BUG", CS%buoy_flux_itt_bug, &
-                 "Bug fix of buoyancy iteration", default=.true.)
-  call get_param(param_file, mdl, "ICE_SHELF_SALT_FLUX_ITT_BUG", CS%salt_flux_itt_bug, &
-                 "Bug fix of salt iteration", default=.true.)
-  call get_param(param_file, mdl, "ICE_SHELF_BUOYANCY_FLUX_ITT_THRESHOLD", CS%buoy_flux_itt_threshold, &
+  call get_param(param_file, mdl, "ICE_SHELF_USTAR_FROM_VEL_BUGFIX", CS%ustar_from_vel_bugfix, &
+                 "Bug fix for ice-area weighting of squared ocean velocities "//&
+                 "used to calculate friction velocity under ice shelves", default=.false.)
+  call get_param(param_file, mdl, "ICE_SHELF_BUOYANCY_FLUX_ITT_BUGFIX", CS%buoy_flux_itt_bugfix, &
+                 "Bug fix of buoyancy iteration", default=.true., old_name="ICE_SHELF_BUOYANCY_FLUX_ITT_BUG")
+  call get_param(param_file, mdl, "ICE_SHELF_SALT_FLUX_ITT_BUGFIX", CS%salt_flux_itt_bugfix, &
+                 "Bug fix of salt iteration", default=.true., old_name="ICE_SHELF_SALT_FLUX_ITT_BUG")
+  call get_param(param_file, mdl, "ICE_SHELF_BUOYANCY_FLUX_ITT_THRESHOLD", CS%buoy_flux_tol, &
                  "Convergence criterion of Newton's method for ice shelf "//&
                  "buoyancy iteration.", units="nondim", default=1.0e-4)
 
@@ -1804,8 +1924,8 @@ subroutine initialize_ice_shelf(param_file, ocn_grid, Time, CS, diag, Time_init,
 
     if (new_sim) then
       ! new simulation, initialize ice thickness as in the static case
-      call initialize_ice_thickness(ISS%h_shelf, ISS%area_shelf_h, ISS%hmask, CS%Grid, CS%Grid_in, US, param_file,  &
-            CS%rotate_index, CS%turns)
+      call initialize_ice_thickness(ISS%h_shelf, ISS%area_shelf_h, ISS%hmask, ISS%melt_mask, CS%Grid, CS%Grid_in, &
+                                    US, param_file, CS%rotate_index, CS%turns)
 
     ! next make sure mass is consistent with thickness
       do j=G%jsd,G%jed ; do i=G%isd,G%ied
@@ -1839,6 +1959,8 @@ subroutine initialize_ice_shelf(param_file, ocn_grid, Time, CS, diag, Time_init,
                               "Ice shelf area in cell", "m2", conversion=US%L_to_m**2)
   call register_restart_field(ISS%h_shelf, "h_shelf", .true., CS%restart_CSp, &
                               "ice sheet/shelf thickness", "m", conversion=US%Z_to_m)
+  call register_restart_field(ISS%melt_mask, "melt_mask", .false., CS%restart_CSp, &
+                              "Mask that is >0 where ice-shelf melting is allowed", "none")
 
   if (CS%calve_ice_shelf_bergs) then
     call register_restart_field(ISS%calving, "shelf_calving", .true., CS%restart_CSp, &
@@ -1885,8 +2007,8 @@ subroutine initialize_ice_shelf(param_file, ocn_grid, Time, CS, diag, Time_init,
 
   if (new_sim .and. (.not. (CS%override_shelf_movement .and. CS%mass_from_file))) then
     ! This model is initialized internally or from a file.
-    call initialize_ice_thickness(ISS%h_shelf, ISS%area_shelf_h, ISS%hmask, CS%Grid, CS%Grid_in, US, param_file,&
-          CS%rotate_index, CS%turns)
+    call initialize_ice_thickness(ISS%h_shelf, ISS%area_shelf_h, ISS%hmask, ISS%melt_mask, CS%Grid, CS%Grid_in, &
+                                  US, param_file, CS%rotate_index, CS%turns)
     ! next make sure mass is consistent with thickness
     do j=G%jsd,G%jed ; do i=G%isd,G%ied
       if ((ISS%hmask(i,j) == 1) .or. (ISS%hmask(i,j) == 2) .or. (ISS%hmask(i,j) == 3)) then
@@ -2356,6 +2478,7 @@ subroutine initialize_shelf_mass(G, param_file, CS, ISS, new_sim)
   end select
 
 end subroutine initialize_shelf_mass
+
 !> This subroutine applies net accumulation/ablation at the top surface to the dynamic ice shelf.
 !! acc_rate[m-s]=surf_mass_flux/density_ice is ablation/accumulation rate
 !! positive for accumulation negative for ablation
@@ -2372,14 +2495,13 @@ subroutine change_thickness_using_precip(CS, ISS, G, US, fluxes, time_step, Time
 
   ! locals
   integer :: i, j
-  real ::I_rho_ice
+  real :: I_rho_ice ! The specific volume of ice [R-1 ~> m3 kg-1]
 
   I_rho_ice = 1.0 / CS%density_ice
 
   !update time
 !  CS%Time = Time
 
-
 !    CS%time_step = time_step
     ! update surface mass flux  rate
 !    if (CS%surf_mass_flux_from_file) call update_surf_mass_flux(G, US, CS, ISS, Time)
@@ -2463,7 +2585,7 @@ subroutine ice_shelf_query(CS, G, frac_shelf_h, mass_shelf, data_override_shelf_
   type(ice_shelf_CS),         pointer    :: CS !< ice shelf control structure
   type(ocean_grid_type), intent(in)      :: G  !< A pointer to an ocean grid control structure.
   real, optional, dimension(SZI_(G),SZJ_(G)), intent(out)  :: frac_shelf_h !< Ice shelf area fraction [nondim].
-  real, optional, dimension(SZI_(G),SZJ_(G)), intent(out)  :: mass_shelf !<Ice shelf mass [R Z ~> kg m-2]
+  real, optional, dimension(SZI_(G),SZJ_(G)), intent(out)  :: mass_shelf !< Ice shelf mass [R Z ~> kg m-2]
   logical, optional                      :: data_override_shelf_fluxes !< If true, shelf fluxes can be written using
                                                !! the data_override capability (only for MOSAIC grids)
 
diff --git a/src/ice_shelf/MOM_ice_shelf_dynamics.F90 b/src/ice_shelf/MOM_ice_shelf_dynamics.F90
index 5c9b0b306d..a8b53ad306 100644
--- a/src/ice_shelf/MOM_ice_shelf_dynamics.F90
+++ b/src/ice_shelf/MOM_ice_shelf_dynamics.F90
@@ -1085,7 +1085,7 @@ subroutine IS_dynamics_post_data(time_step, Time, CS, ISS, G)
   real, dimension(SZDI_(G),SZDJ_(G))  :: ice_visc ! area-averaged vertically integrated ice viscosity
                                                   !! [R L2 Z T-1 ~> Pa s m]
   real, dimension(SZDI_(G),SZDJ_(G))  :: basal_tr ! area-averaged taub_beta field related to basal traction,
-                                                  !! [R L1 T-1 ~> Pa s m-1]
+                                                  !! [R L T-1 ~> Pa s m-1]
   real, dimension(SZDIB_(G),SZDJB_(G)) :: surf_slope ! the surface slope of the ice shelf/sheet [nondim]
   real, dimension(SZDIB_(G),SZDJB_(G)) :: ice_speed ! ice sheet flow speed [L T-1 ~> m s-1]
 
@@ -1738,15 +1738,24 @@ subroutine ice_shelf_solve_inner(CS, ISS, G, US, u_shlf, v_shlf, taudx, taudy, H
                         RHSu, RHSv, & ! Right hand side of the stress balance [R L3 Z T-2 ~> m kg s-2]
                         Au, Av, & ! The retarding lateral stress contributions [R L3 Z T-2 ~> kg m s-2]
                         Du, Dv, & ! Velocity changes [L T-1 ~> m s-1]
-                        sum_vec, sum_vec_2, sum_vec_3 !, &
-                        !ubd, vbd   ! Boundary stress contributions [R L3 Z T-2 ~> kg m s-2]
-  real    :: beta_k, dot_p1, resid0tol2, cg_halo, max_cg_halo
+                        sum_vec ! Sum of squares of residuals in stress calculations [m2 kg2 s-4]
+  real, dimension(SZDIB_(G),SZDJB_(G),3) :: sum_vec_3d ! Array used for various residuals
+                                                       ! sum_vec_3d(:,:,1:2) [m s-1] [m kg s-2]
+                                                       ! sum_vec_3d(:,:,3)   [m2 kg2 s-4]
+  real    :: beta_k      ! Ratio of residuals used to update search direction [nondim]
+  real    :: resid0tol2  ! Convergence tolerance times the initial residual [m2 kg2 s-4]
+  real    :: sv3dsum     ! An unused variable returned when taking global sum of residuals [various]
+  real    :: sv3dsums(3) ! The index-wise global sums of sum_vec_3d
+                         ! sv3dsums(:,:,1:2) [m s-1] [m kg s-2]
+                         ! sv3dsums(:,:,3)   [m2 kg2 s-4]
   real    :: alpha_k     ! A scaling factor for iterative corrections [nondim]
-  real    :: resid_scale ! A scaling factor for redimensionalizing the global residuals [m2 L-2 ~> 1]
-                         ! [m2 L-2 ~> 1] [R L3 Z T-2 ~> m kg s-2]
+  real    :: resid_scale ! A scaling factor for redimensionalizing the global residuals
+                         ! [L T-1 ~> m s-1] [R L3 Z T-2 ~> m kg s-2]
   real    :: resid2_scale ! A scaling factor for redimensionalizing the global squared residuals
-                         ! [m2 L-2 ~> 1] [R L3 Z T-2 ~> m kg s-2]
+                         ! [R2 L6 Z2 T-4 ~> m2 kg2 s-4]
   real    :: rhoi_rhow  ! The density of ice divided by a typical water density [nondim]
+  integer :: cg_halo     ! Number of halo vertices to include during a CG iteration
+  integer :: max_cg_halo ! Maximum possible number of halo vertices to include in the CG iterations
   integer :: iter, i, j, isd, ied, jsd, jed, isc, iec, jsc, jec, is, js, ie, je
   integer :: Is_sum, Js_sum, Ie_sum, Je_sum ! Loop bounds for global sums or arrays starting at 1.
   integer :: Isdq, Iedq, Jsdq, Jedq, Iscq, Iecq, Jscq, Jecq, nx_halo, ny_halo
@@ -1763,7 +1772,6 @@ subroutine ice_shelf_solve_inner(CS, ISS, G, US, u_shlf, v_shlf, taudx, taudy, H
   Zu(:,:) = 0 ; Zv(:,:) = 0 ; DIAGu(:,:) = 0 ; DIAGv(:,:) = 0
   Ru(:,:) = 0 ; Rv(:,:) = 0 ; Au(:,:) = 0 ; Av(:,:) = 0 ; RHSu(:,:) = 0 ; RHSv(:,:) = 0
   Du(:,:) = 0 ; Dv(:,:) = 0
-  dot_p1 = 0
 
   ! Determine the loop limits for sums, bearing in mind that the arrays will be starting at 1.
   ! Includes the edge of the tile is at the western/southern bdry (if symmetric)
@@ -1848,23 +1856,24 @@ subroutine ice_shelf_solve_inner(CS, ISS, G, US, u_shlf, v_shlf, taudx, taudy, H
 
     call pass_vector(Au,Av,G%domain, TO_ALL, BGRID_NE)
 
-    sum_vec(:,:) = 0.0 ; sum_vec_2(:,:) = 0.0
+    sum_vec_3d(:,:,1:2) = 0.0
 
     do J=Jscq_sv,Jecq ; do I=Iscq_sv,Iecq
       if (CS%umask(I,J) == 1) then
-        sum_vec(I,J)   = resid_scale * (Zu(I,J) * Ru(I,J))
-        sum_vec_2(I,J) = resid_scale * (Du(I,J) * Au(I,J))
+        sum_vec_3d(I,J,1) = resid_scale * (Zu(I,J) * Ru(I,J))
+        sum_vec_3d(I,J,2) = resid_scale * (Du(I,J) * Au(I,J))
         Ru_old(I,J) = Ru(I,J) ; Zu_old(I,J) = Zu(I,J)
       endif
       if (CS%vmask(I,J) == 1) then
-        sum_vec(I,J)   = sum_vec(I,J)   + resid_scale * (Zv(I,J) * Rv(I,J))
-        sum_vec_2(I,J) = sum_vec_2(I,J) + resid_scale * (Dv(I,J) * Av(I,J))
+        sum_vec_3d(I,J,1) = sum_vec_3d(I,J,1) + resid_scale * (Zv(I,J) * Rv(I,J))
+        sum_vec_3d(I,J,2) = sum_vec_3d(I,J,2) + resid_scale * (Dv(I,J) * Av(I,J))
         Rv_old(I,J) = Rv(I,J) ; Zv_old(I,J) = Zv(I,J)
       endif
     enddo ; enddo
 
-    alpha_k = reproducing_sum( sum_vec, Is_sum, Ie_sum, Js_sum, Je_sum ) / &
-              reproducing_sum( sum_vec_2, Is_sum, Ie_sum, Js_sum, Je_sum )
+    sv3dsum = reproducing_sum( sum_vec_3d(:,:,1:2), Is_sum, Ie_sum, Js_sum, Je_sum, sums=sv3dsums(1:2) )
+
+    alpha_k = sv3dsums(1)/sv3dsums(2)
 
     do J=js,je-1 ; do I=is,ie-1
       if (CS%umask(I,J) == 1) then
@@ -1883,23 +1892,24 @@ subroutine ice_shelf_solve_inner(CS, ISS, G, US, u_shlf, v_shlf, taudx, taudy, H
     ! R,u,v,Z valid region moves in by 1
 
     ! beta_k = (Z \dot R) / (Zold \dot Rold)
-    sum_vec(:,:) = 0.0 ; sum_vec_2(:,:) = 0.0 ; sum_vec_3(:,:) = 0.0
+    sum_vec_3d(:,:,:) = 0.0; sv3dsums(:)=0.0
 
     do J=jscq_sv,jecq ; do i=iscq_sv,iecq
       if (CS%umask(I,J) == 1) then
-        sum_vec(I,J)   = resid_scale  * (Zu(I,J) * Ru(I,J))
-        sum_vec_2(I,J) = resid_scale  * (Zu_old(I,J) * Ru_old(I,J))
-        sum_vec_3(I,J) = resid2_scale * Ru(I,J)**2
+        sum_vec_3d(I,J,1) = resid_scale  * (Zu(I,J) * Ru(I,J))
+        sum_vec_3d(I,J,2) = resid_scale  * (Zu_old(I,J) * Ru_old(I,J))
+        sum_vec_3d(I,J,3) = resid2_scale * Ru(I,J)**2
       endif
       if (CS%vmask(I,J) == 1) then
-        sum_vec(I,J)   = sum_vec(I,J)   + resid_scale  * (Zv(I,J) * Rv(I,J))
-        sum_vec_2(I,J) = sum_vec_2(I,J) + resid_scale  * (Zv_old(I,J) * Rv_old(I,J))
-        sum_vec_3(I,J) = sum_vec_3(I,J) + resid2_scale * Rv(I,J)**2
+        sum_vec_3d(I,J,1) = sum_vec_3d(I,J,1) + resid_scale  * (Zv(I,J) * Rv(I,J))
+        sum_vec_3d(I,J,2) = sum_vec_3d(I,J,2) + resid_scale  * (Zv_old(I,J) * Rv_old(I,J))
+        sum_vec_3d(I,J,3) = sum_vec_3d(I,J,3) + resid2_scale * Rv(I,J)**2
       endif
     enddo ; enddo
 
-    beta_k = reproducing_sum(sum_vec, Is_sum, Ie_sum, Js_sum, Je_sum ) / &
-             reproducing_sum(sum_vec_2, Is_sum, Ie_sum, Js_sum, Je_sum )
+    sv3dsum = reproducing_sum( sum_vec_3d, Is_sum, Ie_sum, Js_sum, Je_sum, sums=sv3dsums )
+
+    beta_k = sv3dsums(1)/sv3dsums(2)
 
     do J=js,je-1 ; do I=is,ie-1
         if (CS%umask(I,J) == 1) Du(I,J) = Zu(I,J) + beta_k * Du(I,J)
@@ -1908,10 +1918,8 @@ subroutine ice_shelf_solve_inner(CS, ISS, G, US, u_shlf, v_shlf, taudx, taudy, H
 
    ! D valid region moves in by 1
 
-    dot_p1 = reproducing_sum( sum_vec_3, Is_sum, Ie_sum, Js_sum, Je_sum )
-
-    !if sqrt(dot_p1) <= (CS%cg_tolerance * resid0)
-    if (dot_p1 <= resid0tol2) then
+    !if sqrt(sv3dsums(3)) <= (CS%cg_tolerance * resid0)
+    if (sv3dsums(3) <= resid0tol2) then
       iters = iter
       conv_flag = 1
       exit
@@ -2538,7 +2546,7 @@ subroutine calc_shelf_driving_stress(CS, ISS, G, US, taudx, taudy, OD)
         endif
 
         if (CS%max_surface_slope>0) then
-          scale = min(CS%max_surface_slope/sqrt((sx**2)+(sy**2)),1.0)
+          scale = CS%max_surface_slope / max( sqrt((sx**2) + (sy**2)), CS%max_surface_slope )
           sx = scale*sx; sy = scale*sy
         endif
 
@@ -3287,9 +3295,9 @@ subroutine calc_shelf_visc(CS, ISS, G, US, u_shlf, v_shlf)
           CS%ice_visc(i,j,1) = (G%areaT(i,j) * max(ISS%h_shelf(i,j),CS%min_h_shelf)) * &
                                max(CS%AGlen_visc(i,j) ,CS%min_ice_visc)
         endif
-        ! Here CS%Aglen_visc(i,j) is the ice viscosity [Pa s ~> R L2 T-1] computed from obs and read from a file
+        ! Here CS%Aglen_visc(i,j) is the ice viscosity [R L2 T-1 ~> Pa s] computed from obs and read from a file
       elseif (model_qp1) then
-        !calculate viscosity at 1 cell-centered quadrature point per cell
+        ! calculate viscosity at 1 cell-centered quadrature point per cell
 
         Visc_coef = (CS%AGlen_visc(i,j))**(-1./n_g)
         ! Units of Aglen_visc [Pa-(n_g) s-1]
diff --git a/src/ice_shelf/MOM_ice_shelf_initialize.F90 b/src/ice_shelf/MOM_ice_shelf_initialize.F90
index ec24aef2d0..d3d4ceb0a3 100644
--- a/src/ice_shelf/MOM_ice_shelf_initialize.F90
+++ b/src/ice_shelf/MOM_ice_shelf_initialize.F90
@@ -31,7 +31,7 @@ module MOM_ice_shelf_initialize
 contains
 
 !> Initialize ice shelf thickness
-subroutine initialize_ice_thickness(h_shelf, area_shelf_h, hmask, G, G_in, US, PF, rotate_index, turns)
+subroutine initialize_ice_thickness(h_shelf, area_shelf_h, hmask, melt_mask, G, G_in, US, PF, rotate_index, turns)
   type(ocean_grid_type), intent(in)    :: G    !< The ocean's grid structure
   type(ocean_grid_type), intent(in)    :: G_in    !< The ocean's unrotated grid structure
   real, dimension(SZDI_(G),SZDJ_(G)), &
@@ -40,7 +40,9 @@ subroutine initialize_ice_thickness(h_shelf, area_shelf_h, hmask, G, G_in, US, P
                          intent(inout) :: area_shelf_h !< The area per cell covered by the ice shelf [L2 ~> m2].
   real, dimension(SZDI_(G),SZDJ_(G)), &
                          intent(inout) :: hmask !< A mask indicating which tracer points are
-                                             !! partly or fully covered by an ice-shelf
+                                             !! partly or fully covered by an ice-shelf [nondim]
+  real, dimension(SZDI_(G),SZDJ_(G)), &
+                         intent(inout) :: melt_mask !< A mask indicating where to allow ice-shelf melting [nondim]
   type(unit_scale_type), intent(in)    :: US !< A structure containing unit conversion factors
   type(param_file_type), intent(in)    :: PF !< A structure to parse for run-time parameters
   logical, intent(in), optional        :: rotate_index !< If true, this is a rotation test
@@ -49,9 +51,10 @@ subroutine initialize_ice_thickness(h_shelf, area_shelf_h, hmask, G, G_in, US, P
   character(len=40)  :: mdl = "initialize_ice_thickness" ! This subroutine's name.
   character(len=200) :: config
   logical :: rotate = .false.
-  real, allocatable, dimension(:,:) :: tmp1_2d ! Temporary array for storing ice shelf input data
-  real, allocatable, dimension(:,:) :: tmp2_2d ! Temporary array for storing ice shelf input data
-  real, allocatable, dimension(:,:) :: tmp3_2d ! Temporary array for storing ice shelf input data
+  real, allocatable, dimension(:,:) :: tmp1_2d ! Temporary array for storing ice shelf input data [Z~>m]
+  real, allocatable, dimension(:,:) :: tmp2_2d ! Temporary array for storing ice shelf input data [L2~>m2]
+  real, allocatable, dimension(:,:) :: tmp3_2d ! Temporary array for storing ice shelf input data [nondim]
+  real, allocatable, dimension(:,:) :: tmp4_2d ! Temporary array for storing ice shelf input data [nondim]
 
   call get_param(PF, mdl, "ICE_PROFILE_CONFIG", config, &
                  "This specifies how the initial ice profile is specified. "//&
@@ -64,20 +67,22 @@ subroutine initialize_ice_thickness(h_shelf, area_shelf_h, hmask, G, G_in, US, P
     allocate(tmp1_2d(G_in%isd:G_in%ied,G_in%jsd:G_in%jed), source=0.0)
     allocate(tmp2_2d(G_in%isd:G_in%ied,G_in%jsd:G_in%jed), source=0.0)
     allocate(tmp3_2d(G_in%isd:G_in%ied,G_in%jsd:G_in%jed), source=0.0)
+    allocate(tmp4_2d(G_in%isd:G_in%ied,G_in%jsd:G_in%jed), source=1.0)
     select case ( trim(config) )
       case ("CHANNEL") ; call initialize_ice_thickness_channel (tmp1_2d, tmp2_2d, tmp3_2d, G_in, US, PF)
-      case ("FILE") ; call initialize_ice_thickness_from_file (tmp1_2d, tmp2_2d, tmp3_2d, G_in, US, PF)
+      case ("FILE") ; call initialize_ice_thickness_from_file (tmp1_2d, tmp2_2d, tmp3_2d, tmp4_2d, G_in, US, PF)
       case ("USER") ; call USER_init_ice_thickness (tmp1_2d, tmp2_2d, tmp3_2d, G_in, US, PF)
       case default  ; call MOM_error(FATAL,"MOM_initialize: Unrecognized ice profile setup "//trim(config))
     end select
     call rotate_array(tmp1_2d,turns, h_shelf)
     call rotate_array(tmp2_2d,turns, area_shelf_h)
     call rotate_array(tmp3_2d,turns, hmask)
+    call rotate_array(tmp4_2d,turns, melt_mask)
     deallocate(tmp1_2d,tmp2_2d,tmp3_2d)
   else
     select case ( trim(config) )
       case ("CHANNEL") ; call initialize_ice_thickness_channel (h_shelf, area_shelf_h, hmask, G, US, PF)
-      case ("FILE") ; call initialize_ice_thickness_from_file (h_shelf, area_shelf_h, hmask, G, US, PF)
+      case ("FILE") ; call initialize_ice_thickness_from_file (h_shelf, area_shelf_h, hmask, melt_mask, G, US, PF)
       case ("USER") ; call USER_init_ice_thickness (h_shelf, area_shelf_h, hmask, G, US, PF)
       case default  ; call MOM_error(FATAL,"MOM_initialize: Unrecognized ice profile setup "//trim(config))
     end select
@@ -86,7 +91,7 @@ subroutine initialize_ice_thickness(h_shelf, area_shelf_h, hmask, G, G_in, US, P
 end subroutine initialize_ice_thickness
 
 !> Initialize ice shelf thickness from file
-subroutine initialize_ice_thickness_from_file(h_shelf, area_shelf_h, hmask, G, US, PF)
+subroutine initialize_ice_thickness_from_file(h_shelf, area_shelf_h, hmask, melt_mask, G, US, PF)
   type(ocean_grid_type), intent(in)    :: G    !< The ocean's grid structure
   real, dimension(SZDI_(G),SZDJ_(G)), &
                          intent(inout) :: h_shelf !< The ice shelf thickness [Z ~> m].
@@ -94,14 +99,16 @@ subroutine initialize_ice_thickness_from_file(h_shelf, area_shelf_h, hmask, G, U
                          intent(inout) :: area_shelf_h !< The area per cell covered by the ice shelf [L2 ~> m2].
   real, dimension(SZDI_(G),SZDJ_(G)), &
                          intent(inout) :: hmask !< A mask indicating which tracer points are
-                                             !! partly or fully covered by an ice-shelf
+                                             !! partly or fully covered by an ice-shelf [nondim]
+  real, dimension(SZDI_(G),SZDJ_(G)), &
+                         intent(inout) :: melt_mask !< A mask indicating where to allow ice-shelf melting [nondim]
   type(unit_scale_type), intent(in)    :: US !< A structure containing unit conversion factors
   type(param_file_type), intent(in)    :: PF !< A structure to parse for run-time parameters
 
   !  This subroutine reads ice thickness and area from a file and puts it into
   !  h_shelf [Z ~> m] and area_shelf_h [L2 ~> m2] (and dimensionless) and updates hmask
   character(len=200) :: filename,thickness_file,inputdir ! Strings for file/path
-  character(len=200) :: thickness_varname, area_varname, hmask_varname  ! Variable name in file
+  character(len=200) :: thickness_varname, area_varname, hmask_varname, melt_mask_varname  ! Variable name in file
   character(len=40)  :: mdl = "initialize_ice_thickness_from_file" ! This subroutine's name.
   integer :: i, j, isc, jsc, iec, jec
   logical :: hmask_set
@@ -127,6 +134,9 @@ subroutine initialize_ice_thickness_from_file(h_shelf, area_shelf_h, hmask, G, U
                  "The name of the area variable in ICE_THICKNESS_FILE.", &
                  default="area_shelf_h")
   hmask_varname="h_mask"
+  call get_param(PF, mdl, "MELT_MASK_VARNAME", melt_mask_varname, &
+                 "The name of the melt mask variable in ICE_THICKNESS_FILE.", &
+                 default="melt_mask")
   if (.not.file_exists(filename, G%Domain)) call MOM_error(FATAL, &
        " initialize_topography_from_file: Unable to open "//trim(filename))
   call MOM_read_data(filename, trim(thickness_varname), h_shelf, G%Domain, scale=US%m_to_Z)
@@ -139,6 +149,12 @@ subroutine initialize_ice_thickness_from_file(h_shelf, area_shelf_h, hmask, G, U
               "from variable "//trim(hmask_varname)//", which does not exist in "//trim(filename))
     hmask_set = .false.
   endif
+  if (field_exists(filename, trim(melt_mask_varname), MOM_domain=G%Domain)) then
+    call MOM_read_data(filename, trim(melt_mask_varname), melt_mask, G%Domain)
+  else
+    melt_mask(:,:)=1.0
+  endif
+
   isc = G%isc ; jsc = G%jsc ; iec = G%iec ; jec = G%jec
 
   if (.not.hmask_set) then
@@ -311,7 +327,7 @@ subroutine initialize_ice_shelf_boundary_channel(u_face_mask_bdry, v_face_mask_b
   character(len=40)  :: mdl = "initialize_ice_shelf_boundary_channel" ! This subroutine's name.
   integer :: i, j, isd, jsd, giec, gjec, gisc, gjsc,gisd,gjsd, isc, jsc, iec, jec, ied, jed
   real    :: input_thick ! The input ice shelf thickness [Z ~> m]
-  real    :: input_vel  ! The input ice velocity per  [L Z T-1 ~> m s-1]
+  real    :: input_vel  ! The input ice velocity at the upstream boundary [L T-1 ~> m s-1]
   real    :: lenlat, len_stress, westlon, lenlon, southlat ! The input positions of the channel boundarises
 
   lenlat = G%len_lat
@@ -649,10 +665,10 @@ subroutine initialize_ice_AGlen(AGlen, ice_viscosity_compute, G, US, PF)
        " initialize_ice_stiffness_from_file: Unable to open "//trim(filename))
 
     if (trim(ice_viscosity_compute) == "OBS") then
-      !AGlen is the ice viscosity [Pa s ~> R L2 T-1] computed from obs and read from a file
+      ! AGlen is the ice viscosity [R L2 T-1 ~> Pa s] computed from obs and read from a file
       call MOM_read_data(filename, trim(varname), AGlen, G%Domain, scale=US%Pa_to_RL2_T2*US%s_to_T)
     else
-      !AGlen is the ice stiffness parameter [Pa-n_g s-1]
+      ! AGlen is the ice stiffness parameter [Pa-n_g s-1]
       call MOM_read_data(filename, trim(varname), AGlen, G%Domain)
     endif
   endif
diff --git a/src/ice_shelf/MOM_ice_shelf_state.F90 b/src/ice_shelf/MOM_ice_shelf_state.F90
index d789c08bd4..6a4dee9a0e 100644
--- a/src/ice_shelf/MOM_ice_shelf_state.F90
+++ b/src/ice_shelf/MOM_ice_shelf_state.F90
@@ -24,6 +24,7 @@ module MOM_ice_shelf_state
   real, pointer, dimension(:,:) :: &
     mass_shelf => NULL(), &    !< The mass per unit area of the ice shelf or sheet [R Z ~> kg m-2].
     area_shelf_h => NULL(), &  !< The area per cell covered by the ice shelf [L2 ~> m2].
+    melt_mask => NULL(), &     !< Mask is > 0 where melting is allowed [nondim]
     h_shelf => NULL(), &       !< the thickness of the shelf [Z ~> m], redundant with mass but may
                                !! make the code more readable
     dhdt_shelf => NULL(), &       !< the change in thickness of the shelf over time [Z T-1 ~> m s-1]
@@ -74,6 +75,7 @@ subroutine ice_shelf_state_init(ISS, G)
 
   allocate(ISS%mass_shelf(isd:ied,jsd:jed), source=0.0 )
   allocate(ISS%area_shelf_h(isd:ied,jsd:jed), source=0.0 )
+  allocate(ISS%melt_mask(isd:ied,jsd:jed), source=1.0 )
   allocate(ISS%h_shelf(isd:ied,jsd:jed), source=0.0 )
   allocate(ISS%dhdt_shelf(isd:ied,jsd:jed), source=0.0 )
   allocate(ISS%hmask(isd:ied,jsd:jed), source=-2.0 )
diff --git a/src/ice_shelf/MOM_marine_ice.F90 b/src/ice_shelf/MOM_marine_ice.F90
index 3fec94e499..f718fcc81f 100644
--- a/src/ice_shelf/MOM_marine_ice.F90
+++ b/src/ice_shelf/MOM_marine_ice.F90
@@ -110,7 +110,7 @@ subroutine iceberg_fluxes(G, US, fluxes, use_ice_shelf, sfc_state, time_step, CS
   type(marine_ice_CS),   pointer       :: CS      !< Pointer to the control structure for MOM_marine_ice
 
   real :: fraz      ! refreezing rate [R Z T-1 ~> kg m-2 s-1]
-  real :: I_dt_LHF  ! The inverse of the timestep times the latent heat of fusion times [Q-1 T-1 ~> kg J-1 s-1].
+  real :: I_dt_LHF  ! The inverse of the timestep times the latent heat of fusion [Q-1 T-1 ~> kg J-1 s-1].
   integer :: i, j, is, ie, js, je, isd, ied, jsd, jed
   is = G%isc ; ie = G%iec ; js = G%jsc ; je = G%jec
   isd = G%isd ; jsd = G%jsd ; ied = G%ied ; jed = G%jed
diff --git a/src/initialization/MOM_fixed_initialization.F90 b/src/initialization/MOM_fixed_initialization.F90
index 78559c72f2..4b28689483 100644
--- a/src/initialization/MOM_fixed_initialization.F90
+++ b/src/initialization/MOM_fixed_initialization.F90
@@ -25,6 +25,7 @@ module MOM_fixed_initialization
 use MOM_shared_initialization, only : read_face_length_list, set_velocity_depth_max, set_velocity_depth_min
 use MOM_shared_initialization, only : set_subgrid_topo_at_vel_from_file
 use MOM_shared_initialization, only : compute_global_grid_integrals
+use MOM_shared_initialization, only : set_meanSL_from_file
 use MOM_unit_scaling, only : unit_scale_type
 
 use user_initialization, only : user_initialize_topography
@@ -59,9 +60,9 @@ subroutine MOM_initialize_fixed(G, US, OBC, PF)
                                                  !! to parse for model parameter values.
 
   ! Local variables
-  character(len=200) :: inputdir   ! The directory where NetCDF input files are.
   character(len=200) :: config
-  logical            :: read_porous_file, OBC_projection_bug, open_corners, enable_bugs
+  logical            :: OBC_projection_bug, open_corners, enable_bugs
+  logical            :: read_porous_file, read_meanSL_file
   character(len=40)  :: mdl = "MOM_fixed_initialization" ! This module's name.
   integer :: I, J
   logical :: debug
@@ -69,52 +70,60 @@ subroutine MOM_initialize_fixed(G, US, OBC, PF)
 # include "version_variable.h"
 
   call callTree_enter("MOM_initialize_fixed(), MOM_fixed_initialization.F90")
-  call log_version(PF, mdl, version, "")
   call get_param(PF, mdl, "DEBUG", debug, default=.false.)
 
-  call get_param(PF, mdl, "INPUTDIR", inputdir, &
-         "The directory in which input files are found.", default=".")
-  inputdir = slasher(inputdir)
-
   ! Set up the parameters of the physical domain (i.e. the grid), G
   call set_grid_metrics(G, PF, US)
 
+  ! Read time mean sea level from file
+  call get_param(PF, mdl, "READ_MEAN_SEA_LEVEL", read_meanSL_file, &
+                 "If true, use a 2D map for time mean sea level, which is used to calculate "// &
+                 "time mean ocean total thickness.", default=.False.)
+  if (read_meanSL_file) &
+    call set_meanSL_from_file(G%meanSL, G, PF, US)
+
   ! Set up the bottom depth, G%bathyT either analytically or from file
   ! This also sets G%max_depth based on the input parameter MAXIMUM_DEPTH,
   ! or, if absent, is diagnosed as G%max_depth = max( G%D(:,:) )
-  call MOM_initialize_topography(G%bathyT, G%max_depth, G, PF, US)
+  call MOM_initialize_topography(G%bathyT, G%max_depth, G, PF, US, meanSL=G%meanSL)
 
   ! To initialize masks, the bathymetry in halo regions must be filled in
   call pass_var(G%bathyT, G%Domain)
 
-  ! Determine the position of any open boundaries
+  ! Determine the position of any open boundaries and create OBC
   call open_boundary_config(G, US, PF, OBC)
 
-  ! Make bathymetry consistent with open boundaries
-  call get_param(PF, mdl, "ENABLE_BUGS_BY_DEFAULT", enable_bugs, &
-                 default=.true., do_not_log=.true.)  ! This is logged from MOM.F90.
-  call get_param(PF, mdl, "OBC_PROJECTION_BUG", OBC_projection_bug, &
-                 "If false, use only interior ocean points at OBCs to specify several "//&
-                 "calculations at OBC points, and it avoids applying a land mask at the bay-like "//&
-                 "intersection of orthogonal OBC segments.  Otherwise the calculation of terms "//&
-                 "like the potential vorticity used in the barotropic solver relies on bathymetry "//&
-                 "or other fields being projected outward across OBCs.  This option changes "//&
-                 "answers for some configurations that use OBCs.", &
-                 default=enable_bugs, do_not_log=.not.associated(OBC))
-  open_corners = .not.OBC_projection_bug
-
-  ! This call sets masks that prohibit flow over any point interpreted as land
+  ! Make bathymetry (if OBC_PROJECTION_BUG) and masks consistent with open boundaries.
   if (associated(OBC)) then
+    call get_param(PF, mdl, "ENABLE_BUGS_BY_DEFAULT", enable_bugs, &
+                   default=.true., do_not_log=.true.)  ! This is logged from MOM.F90.
+    call get_param(PF, mdl, "OBC_PROJECTION_BUG", OBC_projection_bug, &
+                   "If false, use only interior ocean points at OBCs to specify several "//&
+                   "calculations at OBC points, and it avoids applying a land mask at the "//&
+                   "bay-like intersection of orthogonal OBC segments.  Otherwise the "//&
+                   "calculation of terms like the potential vorticity used in the barotropic "//&
+                   "solver relies on bathymetry or other fields being projected outward across "//&
+                   "OBCs.  This option changes answers for some configurations that use OBCs.", &
+                   default=enable_bugs)
+    open_corners = .not.OBC_projection_bug
+
+    if (OBC_projection_bug .and. read_meanSL_file) &
+      ! OBC_projection_bug modifies bathyT outside of the open boundaries, so meanSL would have to be
+      ! modified as well.
+      call MOM_error(FATAL, "MOM_initialize_fixed: To read mean sea level file, "//&
+                     "OBC_PROJECTION_BUG needs to be False.")
+
+    ! This call sets masks that prohibit flow over any point interpreted as land
     if (OBC_projection_bug) &
       call open_boundary_impose_normal_slope(OBC, G, G%bathyT)
-    call initialize_masks(G, PF, US, OBC_dir_u=OBC%segnum_u, OBC_dir_v=OBC%segnum_v, open_corner_OBCs=open_corners)
+    call initialize_masks(G, PF, US, OBC_dir_u=OBC%segnum_u, OBC_dir_v=OBC%segnum_v, &
+                          open_corner_OBCs=open_corners)
+    ! Make OBC mask consistent with land mask
+    call open_boundary_impose_land_mask(OBC, G, G%areaCu, G%areaCv, US)
   else
     call initialize_masks(G, PF, US)
   endif
 
-  ! Make OBC mask consistent with land mask
-  call open_boundary_impose_land_mask(OBC, G, G%areaCu, G%areaCv, US)
-
   if (debug) then
     call hchksum(G%bathyT, 'MOM_initialize_fixed: depth ', G%HI, haloshift=1, unscale=US%Z_to_m)
     call hchksum(G%mask2dT, 'MOM_initialize_fixed: mask2dT ', G%HI)
@@ -123,6 +132,9 @@ subroutine MOM_initialize_fixed(G, US, OBC, PF)
     call qchksum(G%mask2dBu, 'MOM_initialize_fixed: mask2dBu ', G%HI)
   endif
 
+  ! Set up other fixed quantities
+  ! Parameters below are logged under "module MOM_fixed_initialization".
+  call log_version(PF, mdl, version, "")
   ! Modulate geometric scales according to geography.
   call get_param(PF, mdl, "CHANNEL_CONFIG", config, &
                  "A parameter that determines which set of channels are \n"//&
@@ -167,12 +179,12 @@ subroutine MOM_initialize_fixed(G, US, OBC, PF)
   if (read_porous_file) &
     call set_subgrid_topo_at_vel_from_file(G, PF, US)
 
-!    Calculate the value of the Coriolis parameter at the latitude   !
-!  of the q grid points [T-1 ~> s-1].
+  !    Calculate the value of the Coriolis parameter at the latitude   !
+  !  of the q grid points [T-1 ~> s-1].
   call MOM_initialize_rotation(G%CoriolisBu, G, PF, US=US)
-!   Calculate the components of grad f (beta)
+  !   Calculate the components of grad f (beta)
   call MOM_calculate_grad_Coriolis(G%dF_dx, G%dF_dy, G, US=US)
-!   Calculate the square of the Coriolis parameter
+  !   Calculate the square of the Coriolis parameter
   do I=G%IsdB,G%IedB ; do J=G%JsdB,G%JedB
     G%Coriolis2Bu(I,J) = G%CoriolisBu(I,J)**2
   enddo ; enddo
@@ -186,7 +198,7 @@ subroutine MOM_initialize_fixed(G, US, OBC, PF)
 
   call initialize_grid_rotation_angle(G, PF)
 
-! Compute global integrals of grid values for later use in scalar diagnostics !
+  ! Compute global integrals of grid values for later use in scalar diagnostics !
   call compute_global_grid_integrals(G, US=US)
 
   call callTree_leave('MOM_initialize_fixed()')
@@ -194,21 +206,29 @@ subroutine MOM_initialize_fixed(G, US, OBC, PF)
 end subroutine MOM_initialize_fixed
 
 !> MOM_initialize_topography makes the appropriate call to set up the bathymetry in units of [Z ~> m].
-subroutine MOM_initialize_topography(D, max_depth, G, PF, US)
+subroutine MOM_initialize_topography(D, max_depth, G, PF, US, meanSL)
   type(dyn_horgrid_type),           intent(in)  :: G  !< The dynamic horizontal grid type
   real, dimension(G%isd:G%ied,G%jsd:G%jed), &
                                     intent(out) :: D  !< Ocean bottom depth [Z ~> m]
   type(param_file_type),            intent(in)  :: PF !< Parameter file structure
-  real,                             intent(out) :: max_depth !< Maximum depth of model [Z ~> m]
+  real,                             intent(out) :: max_depth !< Maximum depth or geometric thickness,
+                                                             !! with meanSL present, of model [Z ~> m]
   type(unit_scale_type),            intent(in)  :: US !< A dimensional unit scaling type
+  real, dimension(G%isd:G%ied,G%jsd:G%jed), &
+                          optional, intent(in)  :: meanSL !< Mean sea level [Z ~> m]
 
   ! This subroutine makes the appropriate call to set up the bottom depth.
   ! This is a separate subroutine so that it can be made public and shared with
   ! the ice-sheet code or other components.
 
   ! Local variables
+  real :: max_depth_default = -1.e9 ! Default value of MAXIMUM_DEPTH parameter [m]
   character(len=40)  :: mdl = "MOM_initialize_topography" ! This subroutine's name.
   character(len=200) :: config
+  real, dimension(G%isd:G%ied, G%jsd:G%jed) :: D_meanSL ! depth (positive below meanSL) referenced
+                                        ! to meanSL. A temporary field used to diagnose maximum
+                                        ! static column thickness. D_meanSL = D + meanSL [Z ~> m].
+  integer :: i, j
 
   call get_param(PF, mdl, "TOPO_CONFIG", config, &
                  "This specifies how bathymetry is specified: \n"//&
@@ -238,7 +258,8 @@ subroutine MOM_initialize_topography(D, max_depth, G, PF, US)
                  " \t dense - Denmark Strait-like dense water formation and overflow.\n"//&
                  " \t USER - call a user modified routine.", &
                  fail_if_missing=.true.)
-  call get_param(PF, mdl, "MAXIMUM_DEPTH", max_depth, units="m", default=-1.e9, scale=US%m_to_Z, do_not_log=.true.)
+  call get_param(PF, mdl, "MAXIMUM_DEPTH", max_depth, units="m", default=max_depth_default, &
+                 scale=US%m_to_Z, do_not_log=.true.)
   select case ( trim(config) )
     case ("file");      call initialize_topography_from_file(D, G, PF, US)
     case ("flat");      call initialize_topography_named(D, G, PF, config, max_depth, US)
@@ -262,17 +283,27 @@ subroutine MOM_initialize_topography(D, max_depth, G, PF, US)
     case default ;      call MOM_error(FATAL,"MOM_initialize_topography: "// &
       "Unrecognized topography setup '"//trim(config)//"'")
   end select
-  if (max_depth>0.) then
+  if (max_depth /= max_depth_default * US%m_to_Z) then
     call log_param(PF, mdl, "MAXIMUM_DEPTH", max_depth, &
                    "The maximum depth of the ocean.", units="m", unscale=US%Z_to_m)
+    if (trim(config) /= "DOME") then
+      call limit_topography(D, G, PF, max_depth, US)
+    endif
   else
-    max_depth = diagnoseMaximumDepth(D,G)
+    if (present(meanSL)) then
+      D_meanSL(:,:) = 0.0
+      do j=G%jsc,G%jec ; do i=G%isc,G%iec ; D_meanSL(i,j) = D(i,j) + meanSL(i,j) ; enddo ; enddo
+      max_depth = diagnoseMaximumDepth(D_meanSL, G)
+    else
+      max_depth = diagnoseMaximumDepth(D, G)
+    endif
     call log_param(PF, mdl, "!MAXIMUM_DEPTH", max_depth, &
                    "The (diagnosed) maximum depth of the ocean.", &
                    units="m", unscale=US%Z_to_m, like_default=.true.)
-  endif
-  if (trim(config) /= "DOME") then
-    call limit_topography(D, G, PF, max_depth, US)
+    if (trim(config) /= "DOME") then
+      ! MAXIMUM_DEPTH is not set and topography does not need to be trimmed by its maximum depth.
+      call limit_topography(D, G, PF, -max_depth_default * US%m_to_Z, US)
+    endif
   endif
 
 end subroutine MOM_initialize_topography
diff --git a/src/initialization/MOM_grid_initialize.F90 b/src/initialization/MOM_grid_initialize.F90
index 21b8a735d3..4408783db4 100644
--- a/src/initialization/MOM_grid_initialize.F90
+++ b/src/initialization/MOM_grid_initialize.F90
@@ -1135,11 +1135,11 @@ end function Int_dj_dy
 
 !> Extrapolates missing metric data into all the halo regions.
 subroutine extrapolate_metric(var, jh, missing)
-  real, dimension(:,:), intent(inout) :: var     !< The array in which to fill in halos [abitrary]
+  real, dimension(:,:), intent(inout) :: var     !< The array in which to fill in halos in arbitrary units [A]
   integer,              intent(in)    :: jh      !< The size of the halos to be filled
-  real,       optional, intent(in)    :: missing !< The missing data fill value, 0 by default [abitrary]
+  real,       optional, intent(in)    :: missing !< The missing data fill value, 0 by default [A]
   ! Local variables
-  real :: badval ! A bad data value [abitrary]
+  real :: badval ! A bad data value [A]
   integer :: i, j
 
   badval = 0.0 ; if (present(missing)) badval = missing
@@ -1169,8 +1169,8 @@ end subroutine extrapolate_metric
 !> This function implements Adcroft's rule for reciprocals, namely that
 !!   Adcroft_Inv(x) = 1/x for |x|>0 or 0 for x=0.
 function Adcroft_reciprocal(val) result(I_val)
-  real, intent(in) :: val  !< The value being inverted [abitrary]
-  real :: I_val            !< The Adcroft reciprocal of val [abitrary-1]
+  real, intent(in) :: val  !< The value being inverted in arbitrary units [A]
+  real :: I_val            !< The Adcroft reciprocal of val [A-1]
 
   I_val = 0.0
   if (val /= 0.0) I_val = 1.0/val
@@ -1332,6 +1332,7 @@ subroutine initialize_masks(G, PF, US, OBC_dir_u, OBC_dir_v, open_corner_OBCs)
   do j=G%jsd,G%jed ; do I=G%IsdB,G%IedB
     ! This open face length may be revised later.
     G%dy_Cu(I,j) = G%mask2dCu(I,j) * G%dyCu(I,j)
+    G%IdxCu_OBCmask(I,j) = G%OBCmaskCu(I,j) * G%IdxCu(I,j)
     G%areaCu(I,j) = G%dxCu(I,j) * G%dy_Cu(I,j)
     G%IareaCu(I,j) = G%mask2dCu(I,j) * Adcroft_reciprocal(G%areaCu(I,j))
   enddo ; enddo
@@ -1339,6 +1340,7 @@ subroutine initialize_masks(G, PF, US, OBC_dir_u, OBC_dir_v, open_corner_OBCs)
   do J=G%JsdB,G%JedB ; do i=G%isd,G%ied
     ! This open face length may be revised later.
     G%dx_Cv(i,J) = G%mask2dCv(i,J) * G%dxCv(i,J)
+    G%IdyCv_OBCmask(i,J) = G%OBCmaskCv(i,J) * G%IdyCv(i,J)
     G%areaCv(i,J) = G%dyCv(i,J) * G%dx_Cv(i,J)
     G%IareaCv(i,J) = G%mask2dCv(i,J) * Adcroft_reciprocal(G%areaCv(i,J))
   enddo ; enddo
diff --git a/src/initialization/MOM_shared_initialization.F90 b/src/initialization/MOM_shared_initialization.F90
index 9a4be62fc2..08ee0f015d 100644
--- a/src/initialization/MOM_shared_initialization.F90
+++ b/src/initialization/MOM_shared_initialization.F90
@@ -30,6 +30,7 @@ module MOM_shared_initialization
 public read_face_length_list, set_velocity_depth_max, set_velocity_depth_min
 public set_subgrid_topo_at_vel_from_file
 public compute_global_grid_integrals, write_ocean_geometry_file
+public set_meanSL_from_file
 
 ! A note on unit descriptions in comments: MOM6 uses units that can be rescaled for dimensional
 ! consistency testing. These are noted in comments with units like Z, H, L, and T, along with
@@ -136,6 +137,41 @@ function diagnoseMaximumDepth(D, G)
   call max_across_PEs(diagnoseMaximumDepth)
 end function diagnoseMaximumDepth
 
+!> Read time mean ocean sea level from a file
+subroutine set_meanSL_from_file(meanSL, G, param_file, US)
+  type(dyn_horgrid_type),           intent(in)  :: G !< The dynamic horizontal grid type
+  real, dimension(G%isd:G%ied,G%jsd:G%jed), &
+                                    intent(out) :: meanSL !< Mean sea level referenced to a zero
+                                                          !! reference height at tracer points [Z ~> m].
+  type(param_file_type),            intent(in)  :: param_file !< Parameter file structure
+  type(unit_scale_type),            intent(in)  :: US !< A dimensional unit scaling type
+  ! Local variables
+  character(len=200) :: filename, file, inputdir ! Strings for file/path
+  character(len=200) :: varname                  ! Variable name in file
+  character(len=40)  :: mdl = "set_meanSL_from_file" ! This subroutine's name.
+  integer :: i, j
+
+  call callTree_enter(trim(mdl)//"(), MOM_shared_initialization.F90")
+
+  call get_param(param_file, mdl, "INPUTDIR", inputdir, default=".")
+  inputdir = slasher(inputdir)
+  call get_param(param_file, mdl, "MEAN_SEA_LEVEL_FILE", file, &
+                 "The file from which the mean sea level is read.", &
+                 default="mean_sea_level.nc")
+  call get_param(param_file, mdl, "MEAN_SEA_LEVEL_VARNAME", varname, &
+                 "The name of the mean sea level variable in MEAN_SEA_LEVEL_FILE.", &
+                 default="meanSL")
+  filename = trim(inputdir)//trim(file)
+  call log_param(param_file, mdl, "INPUTDIR/TOPO_FILE", filename)
+
+  if (.not.file_exists(filename, G%Domain)) &
+    call MOM_error(FATAL, " "//mdl//": Unable to open "//trim(filename))
+
+  call MOM_read_data(filename, trim(varname), meanSL, G%Domain, scale=US%m_to_Z)
+  call pass_var(meanSL, G%Domain)
+
+  call callTree_leave(trim(mdl)//'()')
+end subroutine set_meanSL_from_file
 
 !> Read gridded depths from file
 subroutine initialize_topography_from_file(D, G, param_file, US)
@@ -884,6 +920,8 @@ subroutine reset_face_lengths_list(G, param_file, US)
 
     ! Count the number of u_width and v_width entries.
     call read_face_length_list(iounit, filename, num_lines, lines)
+  else
+    num_lines = 0
   endif
 
   len_lon = 360.0 ; if (G%len_lon > 0.0) len_lon = G%len_lon
diff --git a/src/initialization/MOM_state_initialization.F90 b/src/initialization/MOM_state_initialization.F90
index 1ea49671a6..d72b843e2c 100644
--- a/src/initialization/MOM_state_initialization.F90
+++ b/src/initialization/MOM_state_initialization.F90
@@ -24,7 +24,6 @@ module MOM_state_initialization
 use MOM_open_boundary, only : fill_temp_salt_segments, setup_OBC_tracer_reservoirs
 use MOM_open_boundary, only : fill_thickness_segments
 use MOM_open_boundary, only : set_initialized_OBC_tracer_reservoirs
-use MOM_grid_initialize, only : initialize_masks, set_grid_metrics
 use MOM_restart, only : restore_state, is_new_run, copy_restart_var, copy_restart_vector
 use MOM_restart, only : restart_registry_lock, MOM_restart_CS
 use MOM_sponge, only : set_up_sponge_field, set_up_sponge_ML_density
@@ -150,7 +149,7 @@ subroutine MOM_initialize_state(u, v, h, tv, Time, G, GV, US, PF, dirs, &
                                                                !! by a floating ice shelf [nondim].
   real, dimension(SZI_(G),SZJ_(G)), &
                      optional, intent(in)   :: mass_shelf      !< The mass per unit area of the overlying
-                                                               !! ice shelf [ R Z ~> kg m-2 ]
+                                                               !! ice shelf [R Z ~> kg m-2]
   type(ocean_OBC_type), optional, pointer   :: OBC_for_bug  !< An open boundary condition control structure
                                                     !! that might be used to store OBC temperatures and
                                                     !! salinities if OBC_RESERVOIR_INIT_BUG is true.
@@ -159,8 +158,6 @@ subroutine MOM_initialize_state(u, v, h, tv, Time, G, GV, US, PF, dirs, &
   real :: dz(SZI_(G),SZJ_(G),SZK_(GV)) ! The layer thicknesses in geopotential (z) units [Z ~> m]
   character(len=200) :: inputdir   ! The directory where NetCDF input files are.
   character(len=200) :: config, h_config
-  real :: H_rescale   ! A rescaling factor for thicknesses from the representation in
-                      ! a restart file to the internal representation in this run [various units ~> 1]
   real :: dt          ! The baroclinic dynamics timestep for this run [T ~> s].
 
   logical :: from_Z_file, useALE
@@ -2043,7 +2040,6 @@ subroutine initialize_sponges_file(G, GV, US, use_temperature, tv, u, v, depth_t
   ! Local variables
   real, allocatable, dimension(:,:,:) :: eta ! The target interface heights [Z ~> m].
   real, allocatable, dimension(:,:,:) :: dz  ! The target interface thicknesses in height units [Z ~> m]
-  real, allocatable, dimension(:,:,:) :: h   ! The target interface thicknesses [H ~> m or kg m-2].
 
   real, dimension (SZI_(G),SZJ_(G),SZK_(GV)) :: &
     tmp, &    ! A temporary array for temperatures [C ~> degC] or other tracers.
@@ -2646,11 +2642,8 @@ subroutine MOM_temp_salt_initialize_from_Z(h, tv, depth_tot, G, GV, US, PF, just
                                    ! from data when finding the initial interface locations in
                                    ! layered mode from a dataset of T and S.
   character(len=64) :: remappingScheme
-  real :: tempAvg  ! Spatially averaged temperatures on a layer [C ~> degC]
-  real :: saltAvg  ! Spatially averaged salinities on a layer [S ~> ppt]
   logical :: om4_remap_via_sub_cells ! If true, use the OM4 remapping algorithm (only used if useALEremapping)
   logical :: do_conv_adj, ignore
-  integer :: nPoints
   integer :: id_clock_routine, id_clock_ALE
 
   id_clock_routine = cpu_clock_id('(Initialize from Z)', grain=CLOCK_ROUTINE)
diff --git a/src/ocean_data_assim/MOM_oda_driver.F90 b/src/ocean_data_assim/MOM_oda_driver.F90
index 3b277578a3..3dada6e41f 100644
--- a/src/ocean_data_assim/MOM_oda_driver.F90
+++ b/src/ocean_data_assim/MOM_oda_driver.F90
@@ -15,9 +15,10 @@ module MOM_oda_driver_mod
 use MOM_ensemble_manager, only : get_ensemble_pelist, get_ensemble_filter_pelist
 use MOM_error_handler, only : stdout, stdlog, MOM_error
 use MOM_io, only : SINGLE_FILE
-use MOM_interp_infra, only : init_extern_field, get_external_field_info
+use MOM_interp_infra, only : init_extern_field
 use MOM_interp_infra, only : time_interp_extern
 use MOM_interpolate, only : external_field
+use MOM_interpolate, only : get_external_field_info
 use MOM_remapping,    only : remappingSchemesDoc
 use MOM_time_manager, only : time_type, real_to_time, get_date
 use MOM_time_manager, only : operator(+), operator(>=), operator(/=)
@@ -125,7 +126,7 @@ module MOM_oda_driver_mod
   integer :: ensemble_id = 0 !< id of the current ensemble member
   integer, pointer, dimension(:,:) :: ensemble_pelist !< PE list for ensemble members
   integer, pointer, dimension(:) :: filter_pelist !< PE list for ensemble members
-  real :: assim_interval !< analysis interval [ T ~> s]
+  real :: assim_interval !< analysis interval [T ~> s]
   ! Profiles local to the analysis domain
   type(ocean_profile_type), pointer :: Profiles => NULL() !< pointer to linked list of all available profiles
   type(ocean_profile_type), pointer :: CProfiles => NULL()!< pointer to linked list of current profiles
diff --git a/src/parameterizations/lateral/MOM_MEKE.F90 b/src/parameterizations/lateral/MOM_MEKE.F90
index 41c98884ba..a16c9ef32a 100644
--- a/src/parameterizations/lateral/MOM_MEKE.F90
+++ b/src/parameterizations/lateral/MOM_MEKE.F90
@@ -372,12 +372,12 @@ subroutine step_forward_MEKE(MEKE, h, SN_u, SN_v, visc, dt, G, GV, US, CS, hu, h
       if (GV%Boussinesq) then
         !$OMP parallel do default(shared)
         do j=js-1,je+1 ; do i=is-1,ie+1
-          depth_tot(i,j) = (G%bathyT(i,j) + G%Z_ref) * GV%Z_to_H
+          depth_tot(i,j) = max(G%meanSL(i,j) + G%bathyT(i,j), 0.0) * GV%Z_to_H
         enddo ; enddo
       else
         !$OMP parallel do default(shared)
         do j=js-1,je+1 ; do i=is-1,ie+1
-          depth_tot(i,j) = (G%bathyT(i,j) + G%Z_ref) * CS%rho_fixed_total_depth * GV%RZ_to_H
+          depth_tot(i,j) = max(G%meanSL(i,j) + G%bathyT(i,j), 0.0) * CS%rho_fixed_total_depth * GV%RZ_to_H
         enddo ; enddo
       endif
     else
@@ -617,7 +617,7 @@ subroutine step_forward_MEKE(MEKE, h, SN_u, SN_v, visc, dt, G, GV, US, CS, hu, h
       !$OMP parallel do default(shared)
       do j=js-1,je+1 ; do I=is-2,ie+1
         ! MEKE_uflux is used here as workspace with units of [L2 T-2 ~> m2 s-2].
-        MEKE_uflux(I,j) = ((G%dy_Cu(I,j)*G%IdxCu(I,j)) * G%OBCmaskCu(I,j)) * &
+        MEKE_uflux(I,j) = (G%dy_Cu(I,j)*G%IdxCu_OBCmask(I,j)) * &
             (MEKE%MEKE(i+1,j) - MEKE%MEKE(i,j))
       ! This would have units of [R Z L2 T-2 ~> kg s-2]
       ! MEKE_uflux(I,j) = ((G%dy_Cu(I,j)*G%IdxCu(I,j)) * &
@@ -627,7 +627,7 @@ subroutine step_forward_MEKE(MEKE, h, SN_u, SN_v, visc, dt, G, GV, US, CS, hu, h
       !$OMP parallel do default(shared)
       do J=js-2,je+1 ; do i=is-1,ie+1
         ! MEKE_vflux is used here as workspace with units of [L2 T-2 ~> m2 s-2].
-        MEKE_vflux(i,J) = ((G%dx_Cv(i,J)*G%IdyCv(i,J)) * G%OBCmaskCv(i,J)) * &
+        MEKE_vflux(i,J) = (G%dx_Cv(i,J)*G%IdyCv_OBCmask(i,J)) * &
             (MEKE%MEKE(i,j+1) - MEKE%MEKE(i,j))
       ! This would have units of [R Z L2 T-2 ~> kg s-2]
       ! MEKE_vflux(i,J) = ((G%dx_Cv(i,J)*G%IdyCv(i,J)) * &
diff --git a/src/parameterizations/lateral/MOM_Zanna_Bolton.F90 b/src/parameterizations/lateral/MOM_Zanna_Bolton.F90
index 075ec9049c..831e10cbb9 100644
--- a/src/parameterizations/lateral/MOM_Zanna_Bolton.F90
+++ b/src/parameterizations/lateral/MOM_Zanna_Bolton.F90
@@ -444,14 +444,8 @@ subroutine ZB2020_lateral_stress(u, v, h, diffu, diffv, G, GV, CS, &
   real, dimension(SZIB_(G),SZJB_(G)), intent(in) :: dx2q    !< dx^2 at q points [L2 ~> m2]
   real, dimension(SZIB_(G),SZJB_(G)), intent(in) :: dy2q    !< dy^2 at q points [L2 ~> m2]
 
-  integer :: is, ie, js, je, Isq, Ieq, Jsq, Jeq, nz
-  integer :: i, j, k, n
-
   call cpu_clock_begin(CS%id_clock_module)
 
-  is  = G%isc  ; ie  = G%iec  ; js  = G%jsc  ; je  = G%jec ; nz = GV%ke
-  Isq = G%IscB ; Ieq = G%IecB ; Jsq = G%JscB ; Jeq = G%JecB
-
   ! Compute attenuation if specified
   call compute_c_diss(G, GV, CS)
 
@@ -498,7 +492,7 @@ subroutine compute_c_diss(G, GV, CS)
   type(ZB2020_CS),         intent(inout) :: CS   !< ZB2020 control structure.
 
   integer :: is, ie, js, je, Isq, Ieq, Jsq, Jeq, nz
-  integer :: i, j, k, n
+  integer :: i, j, k
 
   real :: shear ! Shear in Klower2018 formula at h points [T-1 ~> s-1]
 
@@ -573,7 +567,7 @@ subroutine compute_stress(G, GV, CS)
   real :: vort_sh ! vort_xy*sh_xy in h point [T-2 ~> s-2]
 
   integer :: is, ie, js, je, Isq, Ieq, Jsq, Jeq, nz
-  integer :: i, j, k, n
+  integer :: i, j, k
 
   logical :: sum_sq_flag ! Flag to compute trace
   logical :: vort_sh_scheme_0, vort_sh_scheme_1 ! Flags to compute diagonal trace-free part
@@ -664,7 +658,7 @@ subroutine compute_stress_ANN_collocated(G, GV, CS)
   type(ZB2020_CS),         intent(inout) :: CS   !< ZB2020 control structure.
 
   integer :: is, ie, js, je, Isq, Ieq, Jsq, Jeq, nz
-  integer :: i, j, k, n, m
+  integer :: i, j, k, m
   integer :: ii, jj
   integer :: nij
 
@@ -676,7 +670,6 @@ subroutine compute_stress_ANN_collocated(G, GV, CS)
                                      ! (Txy,Txx,Tyy) [nondim]
   real :: yy(3)                      ! Vector of dimensional
                                      ! output features (Txy,Txx,Tyy) [L2 T-2 ~> m2 s-2]
-  real :: input_norm                 ! Norm of input features [T-1 ~> s-1]
   real :: tmp                        ! Temporal value of squared norm [T-2 ~> s-2]
   integer :: offset                  ! Half the stencil size. Used for selection
   integer :: stencil_points          ! The number of points after flattening
@@ -940,7 +933,7 @@ subroutine filter_velocity_gradients(G, GV, CS)
   integer :: niter                       ! required number of iterations
 
   integer :: is, ie, js, je, Isq, Ieq, Jsq, Jeq, nz
-  integer :: i, j, k, n
+  integer :: i, j, k
 
   niter = CS%HPF_iter
 
diff --git a/src/parameterizations/lateral/MOM_interface_filter.F90 b/src/parameterizations/lateral/MOM_interface_filter.F90
index 12bda8c020..ec899f6533 100644
--- a/src/parameterizations/lateral/MOM_interface_filter.F90
+++ b/src/parameterizations/lateral/MOM_interface_filter.F90
@@ -296,7 +296,7 @@ subroutine filter_interface(h, e, Lsm2_u, Lsm2_v, uhD, vhD, tv, G, GV, US, halo_
     do I=is-1,ie ; uhtot(I,j) = 0.0 ; enddo
     do K=nz,2,-1
       do I=is-1,ie
-        Slope = ((e(i,j,K)-e(i+1,j,K))*G%IdxCu(I,j)) * G%OBCmaskCu(I,j)
+        Slope = (e(i,j,K)-e(i+1,j,K)) * G%IdxCu_OBCmask(I,j)
 
         if (allocated(tv%SpV_avg)) then
           ! This is the fully non-Boussinesq version.
@@ -336,7 +336,7 @@ subroutine filter_interface(h, e, Lsm2_u, Lsm2_v, uhD, vhD, tv, G, GV, US, halo_
     do i=is,ie ; vhtot(i,J) = 0.0 ; enddo
     do K=nz,2,-1
       do i=is,ie
-        Slope = ((e(i,j,K)-e(i,j+1,K))*G%IdyCv(i,J)) * G%OBCmaskCv(i,J)
+        Slope = (e(i,j,K)-e(i,j+1,K)) * G%IdyCv_OBCmask(i,J)
 
         if (allocated(tv%SpV_avg)) then
           ! This is the fully non-Boussinesq version.
@@ -383,9 +383,7 @@ subroutine interface_filter_init(Time, G, GV, US, param_file, diag, CDp, CS)
   character(len=40)  :: mdl = "MOM_interface_filter" ! This module's name.
   ! This include declares and sets the variable "version".
 # include "version_variable.h"
-  real :: grid_sp      ! The local grid spacing [L ~> m]
   real :: interface_filter_time   ! The grid-scale interface height filtering timescale [T ~> s]
-  integer :: i, j
 
   CS%initialized = .true.
   CS%diag => diag
diff --git a/src/parameterizations/lateral/MOM_internal_tides.F90 b/src/parameterizations/lateral/MOM_internal_tides.F90
index 1f51cc99a9..3ddcecee37 100644
--- a/src/parameterizations/lateral/MOM_internal_tides.F90
+++ b/src/parameterizations/lateral/MOM_internal_tides.F90
@@ -48,7 +48,7 @@ module MOM_internal_tides
   integer :: nMode = 1       !< The number of internal tide vertical modes
   integer :: nAngle = 24     !< The number of internal tide angular orientations
   integer :: energized_angle = -1 !< If positive, only this angular band is energized for debugging purposes
-  real    :: dt_itides       !< The timestep for internal tides ray-tracing [s ~> T]
+  real    :: dt_itides       !< The timestep for internal tides ray-tracing [T ~> s]
   real    :: uniform_test_cg !< Uniform group velocity of internal tide
                              !! for testing internal tides [L T-1 ~> m s-1]
   logical :: corner_adv      !< If true, use a corner advection rather than PPM.
@@ -130,7 +130,7 @@ module MOM_internal_tides
   real, allocatable, dimension(:,:) :: tot_quad_loss !< Energy loss rates due to quadratic bottom drag,
                         !! summed over angle, frequency and mode [H Z2 T-3 ~> m3 s-3 or W m-2]
   real, allocatable, dimension(:,:) :: tot_itidal_loss !< Energy loss rates due to small-scale drag,
-                        !! summed over angle, frequency and mode [H Z2 T-3 ~>  m3 s-3 or W m-2]
+                        !! summed over angle, frequency and mode [H Z2 T-3 ~> m3 s-3 or W m-2]
   real, allocatable, dimension(:,:) :: tot_Froude_loss !< Energy loss rates due to wave breaking,
                         !! summed over angle, frequency and mode [H Z2 T-3 ~> m3 s-3 or W m-2]
   real, allocatable, dimension(:,:) :: tot_residual_loss !< Energy loss rates due to residual on slopes,
@@ -338,15 +338,12 @@ subroutine propagate_int_tide(h, tv, Nb, Rho_bot, dt, G, GV, US, inttide_input_C
   real :: U_mag    ! rescaled magnitude of horizontal profile [L Z T-1 ~> m2 s-1]
   real :: W0       ! rescaled magnitude of vertical profile [Z T-1 ~> m s-1]
   real :: c_phase  ! The phase speed [L T-1 ~> m s-1]
-  real :: loss_rate  ! An energy loss rate [T-1 ~> s-1]
+  ! real :: loss_rate  ! An energy loss rate [T-1 ~> s-1]
   real :: Fr2_max    ! The column maximum internal wave Froude number squared [nondim]
   real :: cn_subRO        ! A tiny wave speed to prevent division by zero [L T-1 ~> m s-1]
   real :: en_subRO        ! A tiny energy to prevent division by zero [H Z2 T-2 ~> m3 s-2 or J m-2]
   real :: En_a, En_b                                 ! Energies for time stepping [H Z2 T-2 ~> m3 s-2 or J m-2]
-  real :: En_new, En_check                           ! Energies for debugging [H Z2 T-2 ~> m3 s-2 or J m-2]
   real :: En_sumtmp                                  ! Energies for debugging [H Z2 L2 T-2 ~> m5 s-2 or J]
-  real :: En_initial, Delta_E_check                  ! Energies for debugging [H Z2 T-2 ~> m3 s-2 or J m-2]
-  real :: TKE_Froude_loss_check, TKE_Froude_loss_tot ! Energy losses for debugging [H Z2 T-3 ~> m3 s-3 or W m-2]
   real :: HZ2_T2_to_J_m2                             ! unit conversion factor for Energy from internal units
                                                      ! to mks [T2 kg H-1 Z-2 s-2 ~> kg m-3 or 1]
   real :: J_m2_to_HZ2_T2                             ! unit conversion factor for Energy from mks to internal
@@ -1363,7 +1360,7 @@ subroutine itidal_lowmode_loss(G, GV, US, CS, Nb, Rho_bot, Ub, En, TKE_loss_fixe
     if (En_tot > 0.0) then
       do a=1,CS%nAngle
         frac_per_sector = En(i,j,a,fr,m)/En_tot
-        TKE_loss(i,j,a,fr,m) = frac_per_sector*TKE_loss_tot           ! [H Z2 T-3  ~> m3 s-3 or W m-2]
+        TKE_loss(i,j,a,fr,m) = frac_per_sector*TKE_loss_tot           ! [H Z2 T-3 ~> m3 s-3 or W m-2]
         loss_rate = TKE_loss(i,j,a,fr,m) / (En(i,j,a,fr,m) + En_negl) ! [T-1 ~> s-1]
         En_b = En(i,j,a,fr,m)
         En_a = En(i,j,a,fr,m) / (1.0 + (dt*loss_rate))
@@ -1426,7 +1423,7 @@ subroutine get_lowmode_diffusivity(G, GV, h, tv, US, h_bot, k_bot, j, N2_lay, N2
                                                               !! dissipated within a layer and the
                                                               !! diapycnal diffusivity within that layer,
                                                               !! usually (~Rho_0 / (G_Earth * dRho_lay))
-                                                              !! [H Z T-1 / H Z2 T-3 = T2 Z-1 ~> s2 m-1]
+                                                              !! [T2 Z-1 ~> s2 m-1]
   real,                                 intent(in) :: Kd_max  !< The maximum increment for diapycnal
                                                               !! diffusivity due to TKE-based processes
                                                               !! [H Z T-1 ~> m2 s-1 or kg m-1 s-1].
@@ -1460,7 +1457,7 @@ subroutine get_lowmode_diffusivity(G, GV, h, tv, US, h_bot, k_bot, j, N2_lay, N2
                                                                       !! [H-1 ~> m-1 or m2 kg-1]
 
   ! local variables
-  real :: TKE_loss          ! temp variable to pass value of internal tides TKE loss [R Z-3 T-3 ~> W m-2]
+  real :: TKE_loss          ! temp variable to pass value of internal tides TKE loss [H Z2 T-3 ~> m3 s-3 or W m-2]
   real :: renorm_N          ! renormalization for N profile [H T-1 ~> m s-1 or kg m-2 s-1]
   real :: renorm_N2         ! renormalization for N2 profile [H T-2 ~> m s-2 or kg m-2 s-2]
   real :: tmp_StLau         ! tmp var for renormalization for StLaurent profile [nondim]
@@ -2105,8 +2102,6 @@ subroutine propagate(En, cn, freq, dt, G, GV, US, CS, NAngle, test, halo_size, r
                          intent(inout) :: residual_loss !< internal tide energy loss due
                                                         !! to the residual at slopes [H Z2 T-3 ~> m3 s-3 or W m-2].
   ! Local variables
-  real, dimension(G%IsdB:G%IedB,G%JsdB:G%JedB) :: &
-    speed  ! The magnitude of the group velocity at the q points for corner adv [L T-1 ~> m s-1].
   integer, parameter :: stencil = 2
   real, dimension(SZIB_(G),SZJ_(G)) :: &
     speed_x  ! The magnitude of the group velocity at the Cu points [L T-1 ~> m s-1].
@@ -2648,7 +2643,6 @@ subroutine turning_latitude(En, NAngle, freq2, CS, G, LB)
   real, dimension(1:Nangle) :: En_reflected ! Energy reflected [H Z2 T-2 ~> m3 s-2 or J m-2].
 
   real    :: TwoPi                         ! 2*pi = 6.2831853... [nondim]
-  real    :: Pi_2                          ! pi/2 [nondim]
   real    :: Angle_size                    ! size of beam wedge [rad]
   real    :: I_Angle_size                  ! inverse of size of beam wedge [rad-1]
   real    :: f2
@@ -3256,10 +3250,9 @@ subroutine register_int_tide_restarts(G, GV, US, param_file, CS, restart_CS)
   logical :: non_Bous          ! If true, this run is fully non-Boussinesq
   logical :: Boussinesq        ! If true, this run is fully Boussinesq
   logical :: semi_Boussinesq   ! If true, this run is partially non-Boussinesq
-  logical :: use_int_tides
-  integer :: num_freq, num_angle , num_mode, period_1
-  integer :: isd, ied, jsd, jed, IsdB, IedB, JsdB, JedB, i, j, a, fr, m
-  character(64) :: var_name, cfr, units
+  integer :: num_freq, num_angle, num_mode
+  integer :: isd, ied, jsd, jed, i, j, a, fr, m
+  character(64) :: units
 
   type(axis_info) :: axes_inttides(2)
   real, dimension(:), allocatable :: angles, freqs ! Lables for angles and frequencies [nondim]
@@ -3411,7 +3404,6 @@ subroutine internal_tides_init(Time, G, GV, US, param_file, diag, CS)
   real    :: kappa_h2_factor    ! A roughness scaling factor [nondim]
   real    :: RMS_roughness_frac ! The maximum RMS topographic roughness as a fraction of the
                                 ! nominal ocean depth, or a negative value for no limit [nondim]
-  real    :: period_1           ! The period of the gravest modeled mode [T ~> s]
   real    :: period             ! A tidal period read from namelist [T ~> s]
   real    :: HZ2_T2_to_J_m2     ! unit conversion factor for Energy from internal units
                                 ! to mks [T2 kg H-1 Z-2 s-2 ~> kg m-3 or 1]
@@ -3773,7 +3765,7 @@ subroutine internal_tides_init(Time, G, GV, US, param_file, diag, CS)
   do j=G%jsc,G%jec ; do i=G%isc,G%iec
     ! Restrict RMS topographic roughness to a fraction (10 percent by default) of the column depth.
     if (RMS_roughness_frac >= 0.0) then
-      h2(i,j) = max(min((RMS_roughness_frac*(G%bathyT(i,j)+G%Z_ref))**2, h2(i,j)), 0.0)
+      h2(i,j) = max(min((RMS_roughness_frac * max(G%meanSL(i,j) + G%bathyT(i,j), 0.0))**2, h2(i,j)), 0.0)
     else
       h2(i,j) = max(h2(i,j), 0.0)
     endif
diff --git a/src/parameterizations/lateral/MOM_lateral_mixing_coeffs.F90 b/src/parameterizations/lateral/MOM_lateral_mixing_coeffs.F90
index 5c9130b6f7..bcfabc6cc6 100644
--- a/src/parameterizations/lateral/MOM_lateral_mixing_coeffs.F90
+++ b/src/parameterizations/lateral/MOM_lateral_mixing_coeffs.F90
@@ -206,6 +206,7 @@ subroutine calc_depth_function(G, CS)
   integer :: is, ie, js, je, Isq, Ieq, Jsq, Jeq
   integer :: i, j
   real    :: H0   ! The depth above which KHTH is linearly scaled away [Z ~> m]
+  real    :: h1, h2  ! Temporary total thicknesses [Z ~> m]
   real    :: expo ! exponent used in the depth dependent scaling [nondim]
   is = G%isc ; ie = G%iec ; js = G%jsc ; je = G%jec
   Isq = G%IscB ; Ieq = G%IecB ; Jsq = G%JscB ; Jeq = G%JecB
@@ -224,11 +225,15 @@ subroutine calc_depth_function(G, CS)
   expo = CS%depth_scaled_khth_exp
 !$OMP do
   do j=js,je ; do I=is-1,Ieq
-    CS%Depth_fn_u(I,j) = (MIN(1.0, (0.5*(G%bathyT(i,j) + G%bathyT(i+1,j)) + G%Z_ref)/H0))**expo
+    h1 = max(G%meanSL(i,j) + G%bathyT(i,j), 0.0)
+    h2 = max(G%meanSL(i+1,j) + G%bathyT(i+1,j), 0.0)
+    CS%Depth_fn_u(I,j) = (MIN(1.0, (0.5 * (h1 + h2)) / H0))**expo
   enddo ; enddo
 !$OMP do
   do J=js-1,Jeq ; do i=is,ie
-    CS%Depth_fn_v(i,J) = (MIN(1.0, (0.5*(G%bathyT(i,j) + G%bathyT(i,j+1)) + G%Z_ref)/H0))**expo
+    h1 = max(G%meanSL(i,j) + G%bathyT(i,j), 0.0)
+    h2 = max(G%meanSL(i,j+1) + G%bathyT(i,j+1), 0.0)
+    CS%Depth_fn_v(i,J) = (MIN(1.0, (0.5 * (h1 + h2)) / H0))**expo
   enddo ; enddo
 
 end subroutine calc_depth_function
@@ -841,9 +846,9 @@ subroutine calc_Visbeck_coeffs_old(h, slope_x, slope_y, N2_u, N2_v, G, GV, US, C
   integer :: OBC_dir_v(SZI_(G),SZJB_(G))  ! An integer indicating where there are v OBCs: +1 for
                                  ! northern OBCs, -1 for southern OBCs and 0 at points with no OBCs.
   real :: h4_u(SZIB_(G),SZJ_(G),SZK_(GV)+1)  ! The product of the 4 thicknesses surrounding a u-point
-                                 ! interface or the inward equivalent with OBCs [H4 ~> m4 or kg2 m-4]
+                                 ! interface or the inward equivalent with OBCs [H4 ~> m4 or kg4 m-8]
   real :: h4_v(SZI_(G),SZJB_(G),SZK_(GV)+1)  ! The product of the 4 thicknesses surrounding a v-point
-                                 ! interface or the inward equivalent with OBCs [H4 ~> m4 or kg2 m-4]
+                                 ! interface or the inward equivalent with OBCs [H4 ~> m4 or kg4 m-8]
   integer :: i, j, k, is, ie, js, je, nz
 
   if (.not. CS%initialized) call MOM_error(FATAL, "calc_Visbeck_coeffs_old: "// &
@@ -1047,7 +1052,7 @@ subroutine calc_Eady_growth_rate_2D(CS, G, GV, US, h, e, dzu, dzv, dzSxN, dzSyN,
   real :: dz_neglect ! A negligibly small distance to avoid division by zero [Z ~> m]
   real :: r_crp_dist ! The inverse of the distance over which to scale the cropping [Z-1 ~> m-1]
   real :: dB, dT ! Elevation variables used when cropping [Z ~> m]
-  integer :: i, j, k, l_seg
+  integer :: i, j, k
   logical :: crop
 
   dz_neglect = GV%dZ_subroundoff
@@ -1068,7 +1073,7 @@ subroutine calc_Eady_growth_rate_2D(CS, G, GV, US, h, e, dzu, dzv, dzSxN, dzSyN,
     CS%SN_v(i,j) = 0.0
   enddo ; enddo
 
-  !$OMP parallel do default(shared) private(dnew,dz,weight,l_seg,vint_SN,sum_dz,dT,dB)
+  !$OMP parallel do default(shared) private(dnew,dz,weight,vint_SN,sum_dz,dT,dB)
   do j=G%jsc-1,G%jec+1
     do I=G%isc-1,G%iec
       vint_SN(I) = 0.
@@ -1111,7 +1116,7 @@ subroutine calc_Eady_growth_rate_2D(CS, G, GV, US, h, e, dzu, dzv, dzSxN, dzSyN,
     enddo
   enddo
 
-  !$OMP parallel do default(shared) private(dnew,dz,weight,l_seg,vint_SN,sum_dz,dT,dB)
+  !$OMP parallel do default(shared) private(dnew,dz,weight,vint_SN,sum_dz,dT,dB)
   do J=G%jsc-1,G%jec
     do i=G%isc-1,G%iec+1
       vint_SN(i) = 0.
@@ -1192,6 +1197,7 @@ subroutine calc_slope_functions_using_just_e(h, G, GV, US, CS, e)
   ! real :: dz(SZI_(G),SZJ_(G),SZK_(GV)) ! The vertical distance across each layer [Z ~> m]
   real :: H_cutoff      ! Local estimate of a minimum thickness for masking [H ~> m or kg m-2]
   real :: dZ_cutoff     ! A minimum water column depth for masking [H ~> m or kg m-2]
+  real :: h1, h2        ! Temporary total thicknesses [Z ~> m]
   real :: h_neglect     ! A thickness that is so small it is usually lost
                         ! in roundoff and can be neglected [H ~> m or kg m-2].
   real :: S2            ! Interface slope squared [Z2 L-2 ~> nondim]
@@ -1206,7 +1212,6 @@ subroutine calc_slope_functions_using_just_e(h, G, GV, US, CS, e)
                         ! bathymetric depth for certain calculations.
   integer :: is, ie, js, je, nz
   integer :: i, j, k
-  integer :: l_seg
 
   if (.not. CS%initialized) call MOM_error(FATAL, "calc_slope_functions_using_just_e: "// &
          "Module must be initialized before it is used.")
@@ -1301,9 +1306,10 @@ subroutine calc_slope_functions_using_just_e(h, G, GV, US, CS, e)
       enddo
     else
       do I=is-1,ie
-        if ( min(G%bathyT(i,j), G%bathyT(i+1,j)) + G%Z_ref > dZ_cutoff ) then
-          CS%SN_u(I,j) = G%OBCmaskCu(I,j) * sqrt( CS%SN_u(I,j) / &
-                                                  (max(G%bathyT(i,j), G%bathyT(i+1,j)) + G%Z_ref) )
+        h1 = max(G%meanSL(i,j) + G%bathyT(i,j), 0.0)
+        h2 = max(G%meanSL(i+1,j) + G%bathyT(i+1,j), 0.0)
+        if ( min(h1, h2) > dZ_cutoff ) then
+          CS%SN_u(I,j) = G%OBCmaskCu(I,j) * sqrt( CS%SN_u(I,j) / max(h1, h2) )
         else
           CS%SN_u(I,j) = 0.0
         endif
@@ -1326,9 +1332,10 @@ subroutine calc_slope_functions_using_just_e(h, G, GV, US, CS, e)
         ! There is a primordial horizontal indexing bug on the following line from the previous
         ! versions of the code.  This comment should be deleted by the end of 2024.
         ! if ( min(G%bathyT(i,j), G%bathyT(i+1,j)) + G%Z_ref > dZ_cutoff ) then
-        if ( min(G%bathyT(i,j), G%bathyT(i,j+1)) + G%Z_ref > dZ_cutoff ) then
-          CS%SN_v(i,J) = G%OBCmaskCv(i,J) * sqrt( CS%SN_v(i,J) / &
-                                                  (max(G%bathyT(i,j), G%bathyT(i,j+1)) + G%Z_ref) )
+        h1 = max(G%meanSL(i,j) + G%bathyT(i,j), 0.0)
+        h2 = max(G%meanSL(i,j+1) + G%bathyT(i,j+1), 0.0)
+        if ( min(h1, h2) > dZ_cutoff ) then
+          CS%SN_v(i,J) = G%OBCmaskCv(i,J) * sqrt( CS%SN_v(i,J) / max(h1, h2) )
         else
           CS%SN_v(i,J) = 0.0
         endif
diff --git a/src/parameterizations/lateral/MOM_mixed_layer_restrat.F90 b/src/parameterizations/lateral/MOM_mixed_layer_restrat.F90
index 2cff7cf7c8..ef1e8e7c38 100644
--- a/src/parameterizations/lateral/MOM_mixed_layer_restrat.F90
+++ b/src/parameterizations/lateral/MOM_mixed_layer_restrat.F90
@@ -227,8 +227,8 @@ subroutine mixedlayer_restrat_OM4(h, uhtr, vhtr, tv, forces, dt, h_MLD, VarMix,
   real :: g_Rho0          ! G_Earth/Rho0 times a thickness conversion factor
                           ! [L2 H-1 T-2 R-1 ~> m4 s-2 kg-1 or m7 s-2 kg-2]
   real :: rho_ml(SZI_(G)) ! Potential density relative to the surface [R ~> kg m-3]
-  real :: rml_int_fast(SZI_(G)) ! The integral of density over the mixed layer depth [R H ~> kg m-2 or kg2 m-3]
-  real :: rml_int_slow(SZI_(G)) ! The integral of density over the mixed layer depth [R H ~> kg m-2 or kg2 m-3]
+  real :: rml_int_fast(SZI_(G)) ! The integral of density over the mixed layer depth [R H ~> kg m-2 or kg2 m-5]
+  real :: rml_int_slow(SZI_(G)) ! The integral of density over the mixed layer depth [R H ~> kg m-2 or kg2 m-5]
   real :: SpV_ml(SZI_(G)) ! Specific volume evaluated at the surface pressure [R-1 ~> m3 kg-1]
   real :: SpV_int_fast(SZI_(G)) ! Specific volume integrated through the mixed layer [H R-1 ~> m4 kg-1 or m]
   real :: SpV_int_slow(SZI_(G)) ! Specific volume integrated through the mixed layer [H R-1 ~> m4 kg-1 or m]
@@ -243,7 +243,7 @@ subroutine mixedlayer_restrat_OM4(h, uhtr, vhtr, tv, forces, dt, h_MLD, VarMix,
   real :: h_min           ! The minimum layer thickness [H ~> m or kg m-2].  h_min could be 0.
   real :: h_neglect       ! tiny thickness usually lost in roundoff so can be neglected [H ~> m or kg m-2]
   real :: I4dt            ! 1/(4 dt) [T-1 ~> s-1]
-  real :: Ihtot,Ihtot_slow! Inverses of the total mixed layer thickness [H-1 ~> m-1 or m2 kg-1]
+  real :: Ihtot, Ihtot_slow ! Inverses of the total mixed layer thickness [H-1 ~> m-1 or m2 kg-1]
   real :: a(SZK_(GV))     ! A non-dimensional value relating the overall flux
                           ! magnitudes (uDml & vDml) to the realized flux in a
                           ! layer [nondim].  The vertical sum of a() through the pieces of
@@ -488,7 +488,7 @@ subroutine mixedlayer_restrat_OM4(h, uhtr, vhtr, tv, forces, dt, h_MLD, VarMix,
     u_star = max(CS%ustar_min, 0.5*(U_star_2d(i,j) + U_star_2d(i+1,j)))
 
     absf = 0.5*(abs(G%CoriolisBu(I,J-1)) + abs(G%CoriolisBu(I,J)))
-    ! Compute I_LFront = 1 / (frontal length scale) [m-1]
+    ! Compute I_LFront = 1 / (frontal length scale) [L-1 ~> m-1]
     lfront = 0.5 * (mle_fl_2d(i,j) + mle_fl_2d(i+1,j))
     ! Adcroft reciprocal
     I_LFront = 0.0 ; if (lfront /= 0.0) I_LFront = 1.0/lfront
@@ -510,7 +510,7 @@ subroutine mixedlayer_restrat_OM4(h, uhtr, vhtr, tv, forces, dt, h_MLD, VarMix,
     timescale = timescale * CS%ml_restrat_coef
 
     if (res_upscale) timescale = timescale * res_scaling_fac
-    uDml(I) = timescale * G%OBCmaskCu(I,j)*G%dyCu(I,j)*G%IdxCu(I,j) * &
+    uDml(I) = timescale * G%dyCu(I,j)*G%IdxCu_OBCmask(I,j) * &
         (Rml_av_fast(i+1,j)-Rml_av_fast(i,j)) * (h_vel**2)
 
     ! As above but using the slow filtered MLD
@@ -525,7 +525,7 @@ subroutine mixedlayer_restrat_OM4(h, uhtr, vhtr, tv, forces, dt, h_MLD, VarMix,
     timescale = timescale * CS%ml_restrat_coef2
 
     if (res_upscale) timescale = timescale * res_scaling_fac
-    uDml_slow(I) = timescale * G%OBCmaskCu(I,j)*G%dyCu(I,j)*G%IdxCu(I,j) * &
+    uDml_slow(I) = timescale * G%dyCu(I,j)*G%IdxCu_OBCmask(I,j) * &
         (Rml_av_slow(i+1,j)-Rml_av_slow(i,j)) * (h_vel**2)
 
     if (uDml(I) + uDml_slow(I) == 0.) then
@@ -577,7 +577,7 @@ subroutine mixedlayer_restrat_OM4(h, uhtr, vhtr, tv, forces, dt, h_MLD, VarMix,
   !$OMP do
   do J=js-1,je ; do i=is,ie
     u_star = max(CS%ustar_min, 0.5*(U_star_2d(i,j) + U_star_2d(i,j+1)))
-    ! Compute I_LFront = 1 / (frontal length scale) [m-1]
+    ! Compute I_LFront = 1 / (frontal length scale) [L-1 ~> m-1]
     lfront = 0.5 * (mle_fl_2d(i,j) + mle_fl_2d(i,j+1))
     ! Adcroft reciprocal
     I_LFront = 0.0 ; if (lfront /= 0.0) I_LFront = 1.0/lfront
@@ -600,7 +600,7 @@ subroutine mixedlayer_restrat_OM4(h, uhtr, vhtr, tv, forces, dt, h_MLD, VarMix,
     timescale = timescale * CS%ml_restrat_coef
 
     if (res_upscale) timescale = timescale * res_scaling_fac
-    vDml(i) = timescale * G%OBCmaskCv(i,J)*G%dxCv(i,J)*G%IdyCv(i,J) * &
+    vDml(i) = timescale * G%dxCv(i,J)*G%IdyCv_OBCmask(i,J) * &
         (Rml_av_fast(i,j+1)-Rml_av_fast(i,j)) * (h_vel**2)
 
     ! As above but using the slow filtered MLD
@@ -615,7 +615,7 @@ subroutine mixedlayer_restrat_OM4(h, uhtr, vhtr, tv, forces, dt, h_MLD, VarMix,
     timescale = timescale * CS%ml_restrat_coef2
 
     if (res_upscale) timescale = timescale * res_scaling_fac
-    vDml_slow(i) = timescale * G%OBCmaskCv(i,J)*G%dxCv(i,J)*G%IdyCv(i,J) * &
+    vDml_slow(i) = timescale * G%dxCv(i,J)*G%IdyCv_OBCmask(i,J) * &
         (Rml_av_slow(i,j+1)-Rml_av_slow(i,j)) * (h_vel**2)
 
     if (vDml(i) + vDml_slow(i) == 0.) then
@@ -813,17 +813,16 @@ subroutine mixedlayer_restrat_Bodner(CS, G, GV, US, h, uhtr, vhtr, tv, forces, d
   real :: grid_dsd        ! combination of grid scales [L2 ~> m2]
   real :: h_sml           ! "Little h", the active mixing depth with diurnal cycle removed [H ~> m or kg m-2]
   real :: h_big           ! "Big H", the mixed layer depth based on a time filtered "little h" [H ~> m or kg m-2]
-  real :: grd_b           ! The vertically average gradient of buoyancy [L H-1 T-2 ~> s-2 or m-3 kg-1 s-2]
+  real :: grd_b           ! The vertically average gradient of buoyancy [L H-1 T-2 ~> s-2 or m3 kg-1 s-2]
   real :: psi_mag         ! Magnitude of stream function [L2 H T-1 ~> m3 s-1 or kg s-1]
   real :: h_neglect       ! tiny thickness usually lost in roundoff so can be neglected [H ~> m or kg m-2]
   real :: I4dt            ! 1/(4 dt) [T-1 ~> s-1]
-  real :: Ihtot,Ihtot_slow! Inverses of the total mixed layer thickness [H-1 ~> m-1 or m2 kg-1]
+  real :: Ihtot           ! Inverses of the total mixed layer thickness [H-1 ~> m-1 or m2 kg-1]
   real :: hAtVel          ! Thickness at the velocity points [H ~> m or kg m-2]
   real :: sigint          ! Fractional position within the mixed layer of the interface above a layer [nondim]
   real :: muzb            ! mu(z) at bottom of the layer [nondim]
   real :: muza            ! mu(z) at top of the layer [nondim]
   real :: dh              ! Portion of the layer thickness that is in the mixed layer [H ~> m or kg m-2]
-  real :: res_scaling_fac ! The resolution-dependent scaling factor [nondim]
   real :: Z3_T3_to_m3_s3  ! Conversion factors to undo scaling and permit terms to be raised to a
                           ! fractional power [T3 m3 Z-3 s-3 ~> 1]
   real :: m2_s2_to_Z2_T2  ! Conversion factors to restore scaling after a term is raised to a
@@ -1183,7 +1182,7 @@ subroutine mixedlayer_restrat_Bodner(CS, G, GV, US, h, uhtr, vhtr, tv, forces, d
 
 end subroutine mixedlayer_restrat_Bodner
 
-!> Two time-scale running mean [units of "signal" and "filtered"]
+!> Two time-scale running mean in the same arbitrary units as "signal" and "filtered"
 !!
 !! If signal > filtered, returns running-mean with time scale "tau_growing".
 !! If signal <= filtered, returns running-mean with time scale "tau_decaying".
@@ -1197,8 +1196,8 @@ end subroutine mixedlayer_restrat_Bodner
 !! rmean2ts with tau_growing=0 recovers the "resetting running mean" used in OM4.
 real elemental function rmean2ts(signal, filtered, tau_growing, tau_decaying, dt)
   ! Arguments
-  real, intent(in) :: signal       ! Unfiltered signal [arbitrary units]
-  real, intent(in) :: filtered     ! Current value of running mean [arbitrary units]
+  real, intent(in) :: signal       ! Unfiltered signal in arbitrary units [A]
+  real, intent(in) :: filtered     ! Current value of running mean in the same arbitrary units [A]
   real, intent(in) :: tau_growing  ! Time scale for growing signal [T ~> s]
   real, intent(in) :: tau_decaying ! Time scale for decaying signal [T ~> s]
   real, intent(in) :: dt           ! Time step [T ~> s]
@@ -1251,7 +1250,7 @@ subroutine mixedlayer_restrat_BML(h, uhtr, vhtr, tv, forces, dt, G, GV, US, CS)
   real :: g_Rho0          ! G_Earth/Rho0 times a thickness conversion factor
                           ! [L2 H-1 T-2 R-1 ~> m4 s-2 kg-1 or m7 s-2 kg-2]
   real :: Rho_ml(SZI_(G)) ! Potential density relative to the surface [R ~> kg m-3]
-  real :: rho_int(SZI_(G)) ! The integral of density over the mixed layer depth [R H ~> kg m-2 or kg2 m-3]
+  real :: rho_int(SZI_(G)) ! The integral of density over the mixed layer depth [R H ~> kg m-2 or kg2 m-5]
   real :: SpV_ml(SZI_(G)) ! Specific volume evaluated at the surface pressure [R-1 ~> m3 kg-1]
   real :: SpV_int(SZI_(G)) ! Specific volume integrated through the surface layer [H R-1 ~> m4 kg-1 or m]
   real :: p0(SZI_(G))     ! A pressure of 0 [R L2 T-2 ~> Pa]
@@ -1383,7 +1382,7 @@ subroutine mixedlayer_restrat_BML(h, uhtr, vhtr, tv, forces, dt, G, GV, US, CS)
     timescale = timescale * CS%ml_restrat_coef
 !      timescale = timescale*(2?)*(L_def/L_MLI) * min(EKE/MKE,1.0 + (G%dyCv(i,j)/L_def)**2)
 
-    uDml(I) = timescale * G%OBCmaskCu(I,j)*G%dyCu(I,j)*G%IdxCu(I,j) * &
+    uDml(I) = timescale * G%dyCu(I,j)*G%IdxCu_OBCmask(I,j) * &
         (Rml_av(i+1,j)-Rml_av(i,j)) * (h_vel**2)
 
     if (uDml(I) == 0) then
@@ -1434,7 +1433,7 @@ subroutine mixedlayer_restrat_BML(h, uhtr, vhtr, tv, forces, dt, G, GV, US, CS)
     timescale = timescale * CS%ml_restrat_coef
 !     timescale = timescale*(2?)*(L_def/L_MLI) * min(EKE/MKE,1.0 + (G%dyCv(i,j)/L_def)**2)
 
-    vDml(i) = timescale * G%OBCmaskCv(i,J)*G%dxCv(i,J)*G%IdyCv(i,J) * &
+    vDml(i) = timescale * G%dxCv(i,J)*G%IdyCv_OBCmask(i,J) * &
         (Rml_av(i,j+1)-Rml_av(i,j)) * (h_vel**2)
     if (vDml(i) == 0) then
       do k=1,nkml ; vhml(i,J,k) = 0.0 ; enddo
@@ -1639,7 +1638,6 @@ logical function mixedlayer_restrat_init(Time, G, GV, US, param_file, diag, CS,
   character(len=32)  :: fl_varname ! Name of front-length scale variable in mle_fl_file.
 
 # include "version_variable.h"
-  integer :: i, j
   character(len=200) :: filename, varname
 
   ! Read all relevant parameters and write them to the model log.
@@ -2013,8 +2011,8 @@ end subroutine mixedlayer_restrat_register_restarts
 !! Returns false otherwise.
 logical function mixedlayer_restrat_unit_tests(verbose)
   logical, intent(in) :: verbose !< If true, write results to stdout
+
   ! Local variables
-  type(mixedlayer_restrat_CS) :: CS ! Control structure
   logical :: this_test
 
   print *,'===== mixedlayer_restrat: mixedlayer_restrat_unit_tests =================='
@@ -2066,7 +2064,6 @@ logical function test_answer(verbose, u, u_true, label, tol)
   real, optional,     intent(in) :: tol    !< The tolerance for differences between u and u_true [A]
   ! Local variables
   real :: tolerance ! The tolerance for differences between u and u_true [A]
-  integer :: k
 
   tolerance = 0.0 ; if (present(tol)) tolerance = tol
   test_answer = .false.
diff --git a/src/parameterizations/lateral/MOM_self_attr_load.F90 b/src/parameterizations/lateral/MOM_self_attr_load.F90
index 045027f05c..eff707a412 100644
--- a/src/parameterizations/lateral/MOM_self_attr_load.F90
+++ b/src/parameterizations/lateral/MOM_self_attr_load.F90
@@ -38,7 +38,7 @@ module MOM_self_attr_load
   real :: eta_prop
     !< The partial derivative of eta_sal with the local value of eta [nondim].
   real :: linear_scaling
-    !< Dimensional coefficients for scalar SAL [nondim or Z T2 L-2 R-1 ~> m Pa-1]
+    !< Dimensional coefficients for scalar SAL [nondim] or [Z T2 L-2 R-1 ~> m Pa-1]
   type(sht_CS), allocatable :: sht
     !< Spherical harmonic transforms (SHT) control structure
   integer :: sal_sht_Nd
@@ -205,7 +205,7 @@ subroutine SAL_init(h, tv, G, GV, US, param_file, CS, restart_CS)
   type(vardesc) :: vars(1)            ! used to write ref_pbot file
   type(MOM_field) :: fields(1)        ! used to write ref_pbot file
   logical :: calculate_sal, tides, use_tidal_sal_file
-  integer :: tides_answer_date ! Recover old answers with tides
+  integer :: default_answer_date, tides_answer_date ! Recover old answers with tides
   real :: sal_scalar_value ! Scaling SAL factors [nondim]
   integer :: isd, ied, jsd, jed
 
@@ -267,8 +267,12 @@ subroutine SAL_init(h, tv, G, GV, US, param_file, CS, restart_CS)
     end select
     call pass_var(CS%pbot_ref, G%Domain)
   endif
-  call get_param(param_file, '', "TIDES_ANSWER_DATE", tides_answer_date, default=20230630, &
-                 do_not_log=.True.) ! used to check SAL_USE_BPA
+
+  call get_param(param_file, mdl, "DEFAULT_ANSWER_DATE", default_answer_date, &
+                 "This sets the default value for the various _ANSWER_DATE parameters.", &
+                 default=99991231, do_not_log=.True.) ! used to check SAL_USE_BPA
+  call get_param(param_file, '', "TIDES_ANSWER_DATE", tides_answer_date, &
+                 default=default_answer_date, do_not_log=.True.) ! used to check SAL_USE_BPA
   if (tides_answer_date<=20250131 .and. CS%use_bpa) &
     call MOM_error(FATAL, trim(mdl) // ", SAL_init: SAL_USE_BPA needs to be false to recover "//&
                    "tide answers before 20250131.")
diff --git a/src/parameterizations/lateral/MOM_spherical_harmonics.F90 b/src/parameterizations/lateral/MOM_spherical_harmonics.F90
index 7606ac3ce1..08b5d0ab12 100644
--- a/src/parameterizations/lateral/MOM_spherical_harmonics.F90
+++ b/src/parameterizations/lateral/MOM_spherical_harmonics.F90
@@ -227,7 +227,7 @@ subroutine spherical_harmonics_init(G, param_file, CS)
 
   ! local variables
   real, parameter :: PI = 4.0*atan(1.0) ! 3.1415926... calculated as 4*atan(1) [nondim]
-  real, parameter :: RADIAN = PI / 180.0 ! Degree to Radian constant [rad/degree]
+  real, parameter :: RADIAN = PI / 180.0 ! Degree to Radian constant [radian degree-1]
   real, dimension(SZI_(G),SZJ_(G)) :: sin_clatT ! sine of colatitude at the t-cells [nondim].
   real :: Pmm_coef ! = sqrt{ 1.0/(4.0*PI) * prod[(2k+1)/2k)] } [nondim].
   integer :: is, ie, js, je
diff --git a/src/parameterizations/lateral/MOM_thickness_diffuse.F90 b/src/parameterizations/lateral/MOM_thickness_diffuse.F90
index 1bfa3d340b..7de1723543 100644
--- a/src/parameterizations/lateral/MOM_thickness_diffuse.F90
+++ b/src/parameterizations/lateral/MOM_thickness_diffuse.F90
@@ -783,14 +783,8 @@ subroutine thickness_diffuse_full(h, e, Kh_u, Kh_v, tv, uhD, vhD, cg1, dt, G, GV
                         ! times unit conversion factors [L2 Z-2 T-2 ~> s-2]
   real :: N2_unlim      ! An unlimited estimate of the buoyancy frequency
                         ! times unit conversion factors [L2 Z-2 T-2 ~> s-2]
-  real :: Tl(5)         ! copy of T in local stencil [C ~> degC]
-  real :: mn_T          ! mean of T in local stencil [C ~> degC]
-  real :: mn_T2         ! mean of T**2 in local stencil [C2 ~> degC2]
-  real :: hl(5)         ! Copy of local stencil of H [H ~> m]
-  real :: r_sm_H        ! Reciprocal of sum of H in local stencil [H-1 ~> m-1]
   real :: Z_to_H        ! A conversion factor from heights to thicknesses, perhaps based on
                         ! a spatially variable local density [H Z-1 ~> nondim or kg m-3]
-  real :: Tsgs2(SZI_(G),SZJ_(G),SZK_(GV)) ! Sub-grid temperature variance [C2 ~> degC2]
   real :: diag_sfn_x(SZIB_(G),SZJ_(G),SZK_(GV)+1)       ! Diagnostic of the x-face streamfunction
                                                         ! [H L2 T-1 ~> m3 s-1 or kg s-1]
   real :: diag_sfn_unlim_x(SZIB_(G),SZJ_(G),SZK_(GV)+1) ! Diagnostic of the x-face streamfunction before
@@ -858,7 +852,7 @@ subroutine thickness_diffuse_full(h, e, Kh_u, Kh_v, tv, uhD, vhD, cg1, dt, G, GV
   if (CS%use_FGNV_streamfn .and. .not. associated(cg1)) call MOM_error(FATAL, &
        "cg1 must be associated when using FGNV streamfunction.")
 
-  !$OMP parallel default(shared) private(hl,r_sm_H,Tl,mn_T,mn_T2)
+  !$OMP parallel default(shared)
   ! Find the maximum and minimum permitted streamfunction.
   !$OMP do
   do j=js-1,je+1 ; do i=is-1,ie+1
@@ -904,7 +898,7 @@ subroutine thickness_diffuse_full(h, e, Kh_u, Kh_v, tv, uhD, vhD, cg1, dt, G, GV
   !$OMP                                  h_neglect2,hn_2,I_slope_max2,int_slope_u,KH_u,uhtot, &
   !$OMP                                  h_frac,h_avail_rsum,uhD,h_avail,Work_u,CS,slope_x,cg1, &
   !$OMP                                  diag_sfn_x,diag_sfn_unlim_x,N2_floor,EOSdom_u,EOSdom_h1, &
-  !$OMP                                  use_stanley,Tsgs2,present_slope_x,G_rho0,Slope_x_PE,hN2_x_PE) &
+  !$OMP                                  use_stanley,present_slope_x,G_rho0,Slope_x_PE,hN2_x_PE) &
   !$OMP                          private(drdiA,drdiB,drdkL,drdkR,pres_u,T_u,S_u,G_scale, &
   !$OMP                                  drho_dT_u,drho_dS_u,hg2A,hg2B,hg2L,hg2R,haA, &
   !$OMP                                  drho_dT_dT_h,scrap,pres_h,T_h,S_h,N2_unlim,  &
@@ -1086,7 +1080,7 @@ subroutine thickness_diffuse_full(h, e, Kh_u, Kh_v, tv, uhD, vhD, cg1, dt, G, GV
             if (present_slope_x) then
               Slope = slope_x(I,j,k)
             else
-              Slope = ((e(i+1,j,K)-e(i,j,K))*G%IdxCu(I,j)) * G%OBCmaskCu(I,j)
+              Slope = (e(i+1,j,K)-e(i,j,K)) * G%IdxCu_OBCmask(I,j)
             endif
             if (CS%id_slope_x > 0) CS%diagSlopeX(I,j,k) = Slope
             Sfn_unlim_u(I,K) = -(KH_u(I,j,K)*G%dy_Cu(I,j))*Slope
@@ -1219,7 +1213,7 @@ subroutine thickness_diffuse_full(h, e, Kh_u, Kh_v, tv, uhD, vhD, cg1, dt, G, GV
   !$OMP                                  h_neglect2,int_slope_v,KH_v,vhtot,h_frac,h_avail_rsum, &
   !$OMP                                  I_slope_max2,vhD,h_avail,Work_v,CS,slope_y,cg1,hn_2,&
   !$OMP                                  diag_sfn_y,diag_sfn_unlim_y,N2_floor,EOSdom_v,use_stanley,&
-  !$OMP                                  Tsgs2, present_slope_y,G_rho0,Slope_y_PE,hN2_y_PE)  &
+  !$OMP                                  present_slope_y,G_rho0,Slope_y_PE,hN2_y_PE)  &
   !$OMP                          private(drdjA,drdjB,drdkL,drdkR,pres_v,T_v,S_v,S_h,S_hr,    &
   !$OMP                                  drho_dT_v,drho_dS_v,hg2A,hg2B,hg2L,hg2R,haA,G_scale, &
   !$OMP                                  drho_dT_dT_h,drho_dT_dT_hr,scrap,pres_h,T_h,T_hr,   &
@@ -1406,7 +1400,7 @@ subroutine thickness_diffuse_full(h, e, Kh_u, Kh_v, tv, uhD, vhD, cg1, dt, G, GV
             if (present_slope_y) then
               Slope = slope_y(i,J,k)
             else
-              Slope = ((e(i,j+1,K)-e(i,j,K))*G%IdyCv(i,J)) * G%OBCmaskCv(i,J)
+              Slope = (e(i,j+1,K)-e(i,j,K)) * G%IdyCv_OBCmask(i,J)
             endif
             if (CS%id_slope_y > 0) CS%diagSlopeY(I,j,k) = Slope
             Sfn_unlim_v(i,K) = -((KH_v(i,J,K)*G%dx_Cv(i,J))*Slope)
diff --git a/src/parameterizations/lateral/MOM_wave_drag.F90 b/src/parameterizations/lateral/MOM_wave_drag.F90
index a507c762c1..ed60066f0e 100644
--- a/src/parameterizations/lateral/MOM_wave_drag.F90
+++ b/src/parameterizations/lateral/MOM_wave_drag.F90
@@ -21,6 +21,10 @@ module MOM_wave_drag
   integer :: nf                                 !< Number of filters to be used in the simulation
   real, allocatable, dimension(:,:,:) :: coef_u !< frequency-dependent drag coefficients [H T-1 ~> m s-1]
   real, allocatable, dimension(:,:,:) :: coef_v !< frequency-dependent drag coefficients [H T-1 ~> m s-1]
+  real, allocatable, dimension(:,:,:) :: coef_uv !< frequency-dependent drag coefficients [H T-1 ~> m s-1]
+  real, allocatable, dimension(:,:,:) :: coef_vu !< frequency-dependent drag coefficients [H T-1 ~> m s-1]
+  logical :: tensor_drag                        !< If true, include the off-diagonal components of the
+                                                !! wave drag tensor for computing the wave drag
 end type wave_drag_CS
 
 contains
@@ -38,7 +42,7 @@ subroutine wave_drag_init(param_file, wave_drag_file, G, GV, US, CS)
   character(len=40)  :: mdl = "MOM_wave_drag"          !< This module's name
   character(len=50)  :: filter_name_str                !< List of drag coefficients to be used
   character(len=2),  allocatable, dimension(:) :: filter_names !< Names of drag coefficients
-  character(len=80)  :: var_names(2)                   !< Names of variables in wave_drag_file
+  character(len=80)  :: var_names(4)                   !< Names of variables in wave_drag_file
   character(len=200) :: mesg
   real               :: var_scale                      !< Scaling factors of drag coefficients [nondim]
   integer            :: c
@@ -53,8 +57,12 @@ subroutine wave_drag_init(param_file, wave_drag_file, G, GV, US, CS)
 
   allocate(CS%coef_u(G%IsdB:G%IedB,G%jsd:G%jed,CS%nf)) ; CS%coef_u(:,:,:) = 0.0
   allocate(CS%coef_v(G%isd:G%ied,G%JsdB:G%JedB,CS%nf)) ; CS%coef_v(:,:,:) = 0.0
+  allocate(CS%coef_uv(G%IsdB:G%IedB,G%jsd:G%jed,CS%nf)) ; CS%coef_uv(:,:,:) = 0.0
+  allocate(CS%coef_vu(G%isd:G%ied,G%JsdB:G%JedB,CS%nf)) ; CS%coef_vu(:,:,:) = 0.0
   allocate(filter_names(CS%nf)) ; read(filter_name_str, *) filter_names
 
+  CS%tensor_drag = .false.
+
   if (len_trim(wave_drag_file) > 0) then
     do c=1,CS%nf
       call get_param(param_file, mdl, "BT_"//trim(filter_names(c))//"_DRAG_U", &
@@ -65,11 +73,21 @@ subroutine wave_drag_init(param_file, wave_drag_file, G, GV, US, CS)
                      var_names(2), "The name of the variable in BT_WAVE_DRAG_FILE "//&
                      "for the drag coefficient of the "//trim(filter_names(c))//&
                      " frequency at v points.", default="")
+      call get_param(param_file, mdl, "BT_"//trim(filter_names(c))//"_DRAG_UV", &
+                     var_names(3), "The name of the variable in BT_WAVE_DRAG_FILE "//&
+                     "for the drag coefficient of the "//trim(filter_names(c))//&
+                     " frequency at u points, corresponding to the off-diagonal "//&
+                     "component of the wave drag tensor.", default="")
+      call get_param(param_file, mdl, "BT_"//trim(filter_names(c))//"_DRAG_VU", &
+                     var_names(4), "The name of the variable in BT_WAVE_DRAG_FILE "//&
+                     "for the drag coefficient of the "//trim(filter_names(c))//&
+                     " frequency at v points, corresponding to the off-diagonal "//&
+                     "component of the wave drag tensor.", default="")
       call get_param(param_file, mdl, "BT_"//trim(filter_names(c))//"_DRAG_SCALE", &
                      var_scale, "A scaling factor for the drag coefficient of the "//&
                      trim(filter_names(c))//" frequency.", default=1.0, units="nondim")
 
-      if (len_trim(var_names(1))+len_trim(var_names(2))>0 .and. var_scale>0.0) then
+      if (len_trim(var_names(1))>0 .and. len_trim(var_names(2))>0 .and. var_scale>0.0) then
         call MOM_read_data(wave_drag_file, trim(var_names(1)), CS%coef_u(:,:,c), G%Domain, &
                            position=EAST_FACE, scale=var_scale*GV%m_to_H*US%T_to_s)
         call MOM_read_data(wave_drag_file, trim(var_names(2)), CS%coef_v(:,:,c), G%Domain, &
@@ -77,6 +95,17 @@ subroutine wave_drag_init(param_file, wave_drag_file, G, GV, US, CS)
         call pass_vector(CS%coef_u(:,:,c), CS%coef_v(:,:,c), G%domain, &
                          direction=To_All+SCALAR_PAIR)
 
+        if (len_trim(var_names(3))>0 .and. len_trim(var_names(4))>0) then
+          CS%tensor_drag = .true.
+
+          call MOM_read_data(wave_drag_file, trim(var_names(3)), CS%coef_uv(:,:,c), G%Domain, &
+                             position=EAST_FACE, scale=var_scale*GV%m_to_H*US%T_to_s)
+          call MOM_read_data(wave_drag_file, trim(var_names(4)), CS%coef_vu(:,:,c), G%Domain, &
+                             position=NORTH_FACE, scale=var_scale*GV%m_to_H*US%T_to_s)
+          call pass_vector(CS%coef_uv(:,:,c), CS%coef_vu(:,:,c), G%domain, &
+                           direction=To_All+SCALAR_PAIR)
+        endif
+
         write(mesg, *) "MOM_wave_drag: ", trim(filter_names(c)), &
                        " coefficients read from file, scaling factor = ", var_scale
         call MOM_error(NOTE, trim(mesg))
@@ -101,27 +130,40 @@ subroutine wave_drag_calc(u, v, drag_u, drag_v, G, CS)
                                                        !! and scaled frequency-dependent drag [L2 T-2 ~> m2 s-2]
 
   ! Local variables
-  integer :: is, ie, js, je, i, j, k
+  integer :: is, ie, js, je, i, j, c
 
   is = G%isc ; ie = G%iec ; js = G%jsc ; je = G%jec
 
-  Drag_u(:,:) = 0.0 ; Drag_v(:,:) = 0.0
-
-  !$OMP do
-  do k=1,CS%nf ; do j=js,je ; do I=is-1,ie
-    Drag_u(I,j) = Drag_u(I,j) + u(I,j,k) * CS%coef_u(I,j,k)
-  enddo ; enddo ; enddo
-
-  !$OMP do
-  do k=1,CS%nf ; do J=js-1,je ; do i=is,ie
-    Drag_v(i,J) = Drag_v(i,J) + v(i,J,k) * CS%coef_v(i,J,k)
-  enddo ; enddo ; enddo
+  drag_u(:,:) = 0.0 ; drag_v(:,:) = 0.0
+
+  if (CS%tensor_drag) then
+    call pass_vector(u(:,:,1:CS%nf), v(:,:,1:CS%nf), G%domain, direction=To_All+SCALAR_PAIR)
+    !$OMP do
+    do j=js,je ; do I=is-1,ie ; do c=1,CS%nf ; if (G%mask2dCu(I,j) * CS%coef_u(I,j,c) > 0.0) then
+      drag_u(I,j) = drag_u(I,j) + (u(I,j,c) * CS%coef_u(I,j,c) + &
+                    0.25 * ((v(i+1,J,c) + v(i,J-1,c)) + (v(i,J,c) + v(i+1,J-1,c))) * CS%coef_uv(I,j,c))
+    endif ; enddo ; enddo ; enddo
+    !$OMP do
+    do J=js-1,je ; do i=is,ie ; do c=1,CS%nf ; if (G%mask2dCv(i,J) * CS%coef_v(i,J,c) > 0.0) then
+      drag_v(i,J) = drag_v(i,J) + (v(i,J,c) * CS%coef_v(i,J,c) + &
+                    0.25 * ((u(I-1,j,c) + u(I,j+1,c)) + (u(I,j,c) + u(I-1,j+1,c))) * CS%coef_vu(i,J,c))
+    endif ; enddo ; enddo ; enddo
+  else ! (.not.CS%tensor_drag)
+    !$OMP do
+    do j=js,je ; do I=is-1,ie ; do c=1,CS%nf ; if (G%mask2dCu(I,j) * CS%coef_u(I,j,c) > 0.0) then
+      drag_u(I,j) = drag_u(I,j) + u(I,j,c) * CS%coef_u(I,j,c)
+    endif ; enddo ; enddo ; enddo
+    !$OMP do
+    do J=js-1,je ; do i=is,ie ; do c=1,CS%nf ; if (G%mask2dCv(i,J) * CS%coef_v(i,J,c) > 0.0) then
+      drag_v(i,J) = drag_v(i,J) + v(i,J,c) * CS%coef_v(i,J,c)
+    endif ; enddo ; enddo ; enddo
+  endif ! (CS%tensor_drag)
 
 end subroutine wave_drag_calc
 
 !> \namespace mom_wave_drag
 !!
-!! By Chengzhu Xu (chengzhu.xu@oregonstate.edu) and Edward D. Zaron, December 2024
+!! By Chengzhu Xu (chengzhu.xu@oregonstate.edu) and Edward D. Zaron
 !!
 !! This module calculates the net effects of the frequency-dependent internal wave drag applied to
 !! the tidal velocities, and returns the sum of products of frequency-dependent drag coefficients
@@ -130,6 +172,9 @@ end subroutine wave_drag_calc
 !! the number of drag coefficients cannot exceed that of the streaming filters, and the names of
 !! drag coefficients should match those of the streaming filters. The frequency-dependent drag
 !! coefficients are read from the same file for the linear drag coefficients in MOM_barotropic.
+!!
+!! Reference: Xu, C., & Zaron, E. D. (2025). Parameterization of frequency-dependent internal wave drag.
+!! Journal of Advances in Modeling Earth Systems, 17, e2025MS005126. https://doi.org/10.1029/2025MS005126
 
 end module MOM_wave_drag
 
diff --git a/src/parameterizations/stochastic/MOM_stochastics.F90 b/src/parameterizations/stochastic/MOM_stochastics.F90
index 66f9dec0ea..cff7ffeadd 100644
--- a/src/parameterizations/stochastic/MOM_stochastics.F90
+++ b/src/parameterizations/stochastic/MOM_stochastics.F90
@@ -53,14 +53,14 @@ module MOM_stochastics
                               !! dissipation rate used to set the amplitude of SKEBS [nondim]
   real    :: skeb_frict_coef  !< If skeb_use_frict is true, then skeb_gm_coef * GM_work is added to the
                               !! dissipation rate used to set the amplitude of SKEBS [nondim]
-  real, allocatable :: skeb_diss(:,:,:) !< Dissipation rate used to set amplitude of SKEBS [L2 T-3 ~> m2 s-2]
+  real, allocatable :: skeb_diss(:,:,:) !< Dissipation rate used to set amplitude of SKEBS [L2 T-3 ~> m2 s-3]
                                         !! Index into this at h points.
   ! stochastic patterns
   real, allocatable :: sppt_wts(:,:)  !< Random pattern for ocean SPPT
-                                      !! tendencies with a number between 0 and 2
-  real, allocatable :: skeb_wts(:,:)  !< Random pattern for ocean SKEB
-  real, allocatable :: epbl1_wts(:,:) !< Random pattern for K.E. generation
-  real, allocatable :: epbl2_wts(:,:) !< Random pattern for K.E. dissipation
+                                      !! tendencies with a number between 0 and 2 [nondim]
+  real, allocatable :: skeb_wts(:,:)  !< Random pattern for ocean SKEB [nondim]
+  real, allocatable :: epbl1_wts(:,:) !< Random pattern for K.E. generation [nondim]
+  real, allocatable :: epbl2_wts(:,:) !< Random pattern for K.E. dissipation [nondim]
   type(time_type), pointer :: Time !< Pointer to model time (needed for sponges)
   type(diag_ctrl), pointer :: diag=>NULL() !< A structure that is used to regulate the
 
diff --git a/src/parameterizations/vertical/MOM_ALE_sponge.F90 b/src/parameterizations/vertical/MOM_ALE_sponge.F90
index ebbba53b37..a0331c6395 100644
--- a/src/parameterizations/vertical/MOM_ALE_sponge.F90
+++ b/src/parameterizations/vertical/MOM_ALE_sponge.F90
@@ -21,7 +21,8 @@ module MOM_ALE_sponge
 use MOM_file_parser,   only : get_param, log_param, log_version, param_file_type
 use MOM_grid,          only : ocean_grid_type
 use MOM_horizontal_regridding, only : horiz_interp_and_extrap_tracer
-use MOM_interpolate,   only : init_external_field, get_external_field_info, time_interp_external_init
+use MOM_interpolate,   only : init_external_field, time_interp_external_init
+use MOM_interpolate,   only : get_external_field_info
 use MOM_interpolate,   only : external_field
 use MOM_io,            only : axis_info
 use MOM_remapping,     only : remapping_cs, remapping_core_h, initialize_remapping
@@ -141,8 +142,9 @@ module MOM_ALE_sponge
                                    !! It is not clear why this needs to be greater than 0.
 
   !>@{ Diagnostic IDs
-  integer, dimension(MAX_FIELDS_) :: id_sp_tendency  !< Diagnostic ids for tracer
-                                               !! tendencies due to sponges
+  integer, dimension(MAX_FIELDS_) :: id_sp_tendency = reshape([-1], [MAX_FIELDS_], [-1]) !< Diagnostic ids for tracer
+                                                                                         !! tendencies due to sponges.
+                                                                                         !! Init all to -1.
   integer :: id_sp_u_tendency                  !< Diagnostic id for zonal momentum tendency due to
                                                !! Rayleigh damping
   integer :: id_sp_v_tendency                  !< Diagnostic id for meridional momentum tendency due to
@@ -187,7 +189,6 @@ subroutine initialize_ALE_sponge_fixed(Iresttime, G, GV, param_file, CS, data_h,
 # include "version_variable.h"
   character(len=64)  :: remapScheme
   logical :: use_sponge
-  logical :: data_h_to_Z
   logical :: bndExtrapolation = .true. ! If true, extrapolate boundaries
   integer :: default_answer_date  ! The default setting for the various ANSWER_DATE flags.
   logical :: om4_remap_via_sub_cells ! If true, use the OM4 remapping algorithm
@@ -670,7 +671,6 @@ subroutine init_ALE_sponge_diags(Time, G, diag, CS, US)
   CS%diag => diag
 
   do m=1,CS%fldno
-    CS%id_sp_tendency(m) = -1
     if ((trim(CS%Ref_val(m)%unit) == 'none') .or. (len_trim(CS%Ref_val(m)%unit) == 0)) then
       tend_unit = "s-1"
     else
diff --git a/src/parameterizations/vertical/MOM_CVMix_KPP.F90 b/src/parameterizations/vertical/MOM_CVMix_KPP.F90
index bf8de60a27..fa44f1b593 100644
--- a/src/parameterizations/vertical/MOM_CVMix_KPP.F90
+++ b/src/parameterizations/vertical/MOM_CVMix_KPP.F90
@@ -1076,7 +1076,6 @@ subroutine KPP_compute_BLD(CS, G, GV, US, h, Temp, Salt, u, v, tv, uStar, buoyFl
                                                                  ! [L T-1 ~> m s-1]
   real :: StokesXI     ! Stokes similarity parameter [nondim]
   real, dimension( GV%ke )     :: StokesXI_1d ,   StokesVt_1d    !  Parameters of TKE production ratio [nondim]
-  real :: Llimit ! Stable boundary Layer Limit =  vonk Lstar [Z ~> m]
   integer :: kbl ! index of cell containing boundary layer depth
 
   if (CS%Stokes_Mixing .and. .not.associated(Waves)) call MOM_error(FATAL, &
diff --git a/src/parameterizations/vertical/MOM_bkgnd_mixing.F90 b/src/parameterizations/vertical/MOM_bkgnd_mixing.F90
index d6c51201a6..af7fe4a94e 100644
--- a/src/parameterizations/vertical/MOM_bkgnd_mixing.F90
+++ b/src/parameterizations/vertical/MOM_bkgnd_mixing.F90
@@ -335,9 +335,6 @@ subroutine calculate_bkgnd_mixing(h, tv, N2_lay, Kd_lay, Kd_int, Kv_bkgnd, j, G,
   real, dimension(SZI_(G),SZK_(GV)) :: dz   !< Height change across layers [Z ~> m]
   real :: depth_c    !< depth of the center of a layer [H ~> m or kg m-2]
   real :: I_Hmix     !< inverse of fixed mixed layer thickness [H-1 ~> m-1 or m2 kg-1]
-  real :: I_2Omega   !< 1/(2 Omega) [T ~> s]
-  real :: N_2Omega   !  The ratio of the stratification to the Earth's rotation rate [nondim]
-  real :: N02_N2     !  The ratio a reference stratification to the actual stratification [nondim]
   real :: I_x30      !< 2/acos(2) = 1/(sin(30 deg) * acosh(1/sin(30 deg))) [nondim]
   real :: deg_to_rad !< factor converting degrees to radians [radians degree-1], pi/180.
   real :: abs_sinlat !< absolute value of sine of latitude [nondim]
diff --git a/src/parameterizations/vertical/MOM_bulk_mixed_layer.F90 b/src/parameterizations/vertical/MOM_bulk_mixed_layer.F90
index 690688dc1e..b54a1b70d7 100644
--- a/src/parameterizations/vertical/MOM_bulk_mixed_layer.F90
+++ b/src/parameterizations/vertical/MOM_bulk_mixed_layer.F90
@@ -278,7 +278,7 @@ subroutine bulkmixedlayer(h_3d, u_3d, v_3d, tv, fluxes, dt, ea, eb, G, GV, US, C
                      ! over a time step from evaporating fresh water [H ~> m or kg m-2]
     Net_heat, & !   The net heating at the surface over a time step [C H ~> degC m or degC kg m-2]
                 ! Any penetrating shortwave radiation is not included in Net_heat.
-    Net_salt, & ! The surface salt flux into the ocean over a time step [S H  ~> ppt m or ppt kg m-2]
+    Net_salt, & ! The surface salt flux into the ocean over a time step [S H ~> ppt m or ppt kg m-2]
     Idecay_len_TKE, &  ! The inverse of a turbulence decay length scale [H-1 ~> m-1 or m2 kg-1].
     p_ref, &    !   Reference pressure for the potential density governing mixed
                 ! layer dynamics, almost always 0 (or 1e5) [R L2 T-2 ~> Pa].
@@ -1118,7 +1118,7 @@ subroutine mixedlayer_convection(h, d_eb, htot, Ttot, Stot, uhtot, vhtot,      &
   real :: T_precip     !   The temperature of the precipitation [C ~> degC].
   real :: C1_3, C1_6   !  1/3 and 1/6 [nondim]
   real :: En_fn, Frac, x1 !  Nondimensional temporary variables [nondim].
-  real :: dr, dr0      ! Temporary variables [R H ~> kg m-2 or kg2 m-5] or [R-1 H ~> m4 kg-1 or m].
+  real :: dr, dr0      ! Temporary variables [R H ~> kg m-2 or kg2 m-5] or [H R-1 ~> m4 kg-1 or m].
   real :: dr_ent, dr_comp ! Temporary variables [R H ~> kg m-2 or kg2 m-5].
   real :: dr_dh        ! The partial derivative of dr_ent with h_ent [R ~> kg m-3].
   real :: h_min, h_max !   The minimum and maximum estimates for h_ent [H ~> m or kg m-2]
diff --git a/src/parameterizations/vertical/MOM_diabatic_driver.F90 b/src/parameterizations/vertical/MOM_diabatic_driver.F90
index 63470312f3..7c9ec42038 100644
--- a/src/parameterizations/vertical/MOM_diabatic_driver.F90
+++ b/src/parameterizations/vertical/MOM_diabatic_driver.F90
@@ -309,7 +309,7 @@ subroutine diabatic(u, v, h, tv, BLD, fluxes, visc, ADp, CDp, dt, Time_end, &
   real, dimension(SZI_(G),SZK_(GV)) :: &
     pressure    ! The pressure at the middle of each layer [R L2 T-2 ~> Pa].
   real :: H_to_RL2_T2  ! A conversion factor from thicknesses in H to pressure [R L2 T-2 H-1 ~> Pa m-1 or Pa m2 kg-1]
-  integer :: i, j, k, m, is, ie, js, je, nz
+  integer :: i, j, k, is, ie, js, je, nz
   logical :: showCallTree ! If true, show the call tree
 
   real, allocatable, dimension(:,:,:)    :: h_in  ! thickness before thermodynamics [H ~> m or kg m-2]
@@ -594,7 +594,6 @@ subroutine diabatic_ALE_legacy(u, v, h, tv, BLD, fluxes, visc, ADp, CDp, dt, Tim
 
   real, dimension(SZI_(G)) :: &
     p_i ,&      ! Pressure at the interface [R L2 T-2 ~> Pa]
-    d_pres, &   ! pressure change across a layer [R L2 T-2 ~> Pa]
     T_i, &      ! Temperature at the interface [C ~> degC]
     S_i, &      ! Salinity at the interface [S ~> ppt]
     drhodS, &   ! Local change in density w.r.t. salinity using model EOS & state [R C-1 ~> kg m-3 ppt-1]
@@ -1312,7 +1311,6 @@ subroutine diabatic_ALE(u, v, h, tv, BLD, fluxes, visc, ADp, CDp, dt, Time_end,
 
   real, dimension(SZI_(G)) :: &
     p_i ,&      ! Pressure at the interface [R L2 T-2 ~> Pa]
-    d_pres, &   ! pressure change across a layer [R L2 T-2 ~> Pa]
     T_i, &      ! Temperature at the interface [C ~> degC]
     S_i, &      ! Salinity at the interface [S ~> ppt]
     drhodS, &   ! Local change in density w.r.t. salinity using model EOS & state [R C-1 ~> kg m-3 ppt-1]
@@ -3241,10 +3239,8 @@ subroutine diabatic_driver_init(Time, G, GV, US, param_file, useALEalgorithm, di
 # include "version_variable.h"
   character(len=40)  :: mdl = "MOM_diabatic_driver" ! This module's name.
   character(len=48)  :: thickness_units
-  character(len=40)  :: var_name
-  character(len=160) :: var_descript
   logical :: physical_OBL_scheme
-  integer :: isd, ied, jsd, jed, IsdB, IedB, JsdB, JedB, nz, nbands, m
+  integer :: isd, ied, jsd, jed, IsdB, IedB, JsdB, JedB, nz, nbands
   isd  = G%isd  ; ied  = G%ied  ; jsd  = G%jsd  ; jed  = G%jed ; nz = GV%ke
   IsdB = G%IsdB ; IedB = G%IedB ; JsdB = G%JsdB ; JedB = G%JedB
 
diff --git a/src/parameterizations/vertical/MOM_energetic_PBL.F90 b/src/parameterizations/vertical/MOM_energetic_PBL.F90
index 7a67cbb5a5..99c0711fd1 100644
--- a/src/parameterizations/vertical/MOM_energetic_PBL.F90
+++ b/src/parameterizations/vertical/MOM_energetic_PBL.F90
@@ -458,7 +458,7 @@ subroutine energetic_PBL(h_3d, u_3d, v_3d, tv, fluxes, visc, dt, Kd_int, G, GV,
     BBL_Vel_Scale, &       ! The velocity scale used in getting the BBL part of Kd [Z T-1 ~> m s-1]
     BBL_Mix_Length         ! The length scale used in getting the BBL part of Kd [Z ~> m]
   real, dimension(SZI_(G),SZJ_(G)) :: &
-    ! The next 7 diagnostics are terms in the mixed layer TKE budget, all in [R Z3 T-3 ~> W m-2 = kg s-3].
+    ! The next 7 diagnostics are terms in the mixed layer TKE budget, all in [R Z3 T-3 ~> W m-2].
     diag_TKE_wind, &   ! The wind source of TKE [R Z3 T-3 ~> W m-2]
     diag_TKE_MKE, &    ! The resolved KE source of TKE [R Z3 T-3 ~> W m-2]
     diag_TKE_conv, &   ! The convective source of TKE [R Z3 T-3 ~> W m-2]
@@ -477,8 +477,7 @@ subroutine energetic_PBL(h_3d, u_3d, v_3d, tv, fluxes, visc, dt, Kd_int, G, GV,
     diag_mstar_LT, &   ! mstar due to Langmuir turbulence [nondim]
     diag_LA, &         ! Langmuir number [nondim]
     diag_LA_mod, &     ! Modified Langmuir number [nondim]
-    diag_ustar, &      ! The surface boundary layer friction velocity [Z T-1 ~> m s-1]
-    diag_bflx          ! The surface boundary layer buoyancy flux  [Z2 T-3 ~> m2 s-3]
+    diag_ustar         ! The surface boundary layer friction velocity [Z T-1 ~> m s-1]
 
   ! The following variables are only used for diagnosing sensitivities to ePBL settings
   real, dimension(SZK_(GV)+1) :: &
@@ -1028,7 +1027,8 @@ subroutine ePBL_column(h, dz, u, v, T0, S0, dSV_dT, dSV_dS, SpV_dt, TKE_forcing,
   real :: dz_neglect ! A vertical distance that is so small it is usually lost
                     ! in roundoff and can be neglected [Z ~> m].
   real :: dMass     ! The mass per unit area within a layer [Z R ~> kg m-2].
-  real :: dPres     ! The hydrostatic pressure change across a layer [R Z2 T-2 ~> Pa = J m-3].
+  real :: dPres     ! The hydrostatic pressure change across a layer [R Z2 T-2 ~> Pa] or
+                    ! equivalently [R Z2 T-2 ~> J m-3].
   real :: dMKE_max  ! The maximum amount of mean kinetic energy that could be
                     ! converted to turbulent kinetic energy if the velocity in
                     ! the layer below an interface were homogenized with all of
@@ -2068,8 +2068,6 @@ subroutine ePBL_BBL_column(h, dz, u, v, T0, S0, dSV_dT, dSV_dS, SpV_dt, absf, &
     c1, &           ! c1 is used by the tridiagonal solver [nondim].
     Te, &           ! Estimated final values of T in the column [C ~> degC].
     Se, &           ! Estimated final values of S in the column [S ~> ppt].
-    dTe, &          ! Running (1-way) estimates of temperature change [C ~> degC].
-    dSe, &          ! Running (1-way) estimates of salinity change [S ~> ppt].
     hp_a, &         ! An effective pivot thickness of the layer including the effects
                     ! of coupling with layers above [H ~> m or kg m-2].  This is the first term
                     ! in the denominator of b1 in a downward-oriented tridiagonal solver.
@@ -2098,8 +2096,8 @@ subroutine ePBL_BBL_column(h, dz, u, v, T0, S0, dSV_dT, dSV_dS, SpV_dt, absf, &
   real :: dz_neglect ! A vertical distance that is so small it is usually lost
                     ! in roundoff and can be neglected [Z ~> m].
   real :: dMass     ! The mass per unit area within a layer [Z R ~> kg m-2].
-  real :: dPres     ! The hydrostatic pressure change across a layer [R Z2 T-2 ~> Pa = J m-3].
-
+  real :: dPres     ! The hydrostatic pressure change across a layer [R Z2 T-2 ~> Pa] or
+                    ! equivalently [R Z2 T-2 ~> J m-3].
   real :: dt_h      ! The timestep divided by the averages of the vertical distances around
                     ! a layer [T Z-1 ~> s m-1].
   real :: dz_top    ! The distance from the surface [Z ~> m].
@@ -2156,7 +2154,6 @@ subroutine ePBL_BBL_column(h, dz, u, v, T0, S0, dSV_dT, dSV_dS, SpV_dt, absf, &
   real :: min_BBLD, max_BBLD ! Iteration bounds on BBLD [Z ~> m], which are adjusted at each step
   real :: dBBLD_min  ! The change in diagnosed mixed layer depth when the guess is min_BLD [Z ~> m]
   real :: dBBLD_max  ! The change in diagnosed mixed layer depth when the guess is max_BLD [Z ~> m]
-  logical :: BBL_converged ! Flag for convergence of BBLD
   integer :: BBL_it        ! Iteration counter
 
   real :: Surface_Scale ! Surface decay scale for vstar [nondim]
@@ -2777,8 +2774,7 @@ subroutine kappa_eqdisc(shape_func, CS, GV, dz, absf, B_flux, u_star, MLD_guess)
 
   ! variables used for optimizing computations:
   real :: sm_h     ! sigma_max multiplied by boundary layer depth [Z ~> m]
-  real :: sm_h_I   ! inverse of sm_h,[Z-1 ~> m-1]
-  real :: sm_h_I2  ! An inverse variable given by 1.0/(h - sm_h), [Z-1 ~> m-1]
+  real :: sm_h_I   ! inverse of sm_h [Z-1 ~> m-1]
   real :: hz_n     ! z depth to avoid calling hz multiple times [Z ~> m]
   real :: z_minus_sm_h  ! depth z minus \sigma_m * MLD_Guess [Z ~> m]
   real :: z_minus_sm_h2 ! (depth z minus \sigma_m * MLD_Guess)^2 [Z2 ~> m2]
diff --git a/src/parameterizations/vertical/MOM_geothermal.F90 b/src/parameterizations/vertical/MOM_geothermal.F90
index ac12bcdb1b..93347b053a 100644
--- a/src/parameterizations/vertical/MOM_geothermal.F90
+++ b/src/parameterizations/vertical/MOM_geothermal.F90
@@ -370,7 +370,8 @@ subroutine geothermal_in_place(h, tv, dt, G, GV, US, CS, BFlx_geothermal, halo)
   real,                                      intent(in)    :: dt !< Time increment [T ~> s].
   type(unit_scale_type),                     intent(in)    :: US !< A dimensional unit scaling type
   type(geothermal_CS),                       intent(in)    :: CS !< Geothermal heating control struct
-  real, dimension(SZI_(G), SZJ_(G)),         intent(out)   :: BFlx_geothermal !< Geothermal Buoyancy Flux [m2 s-3]
+  real, dimension(SZI_(G), SZJ_(G)),         intent(out)   :: BFlx_geothermal !< Geothermal buoyancy flux
+                                                                 !! in [Z2 T-3 ~> m2 s-3]
   integer,                         optional, intent(in)    :: halo !< Halo width over which to work
 
 
@@ -396,7 +397,7 @@ subroutine geothermal_in_place(h, tv, dt, G, GV, US, CS, BFlx_geothermal, halo)
   real :: Idt           ! inverse of the timestep [T-1 ~> s-1]
   real :: H_to_Pres     ! A conversion factor from thicknesses to pressure [R L2 T-2 H-1 ~> Pa m-1 or Pa m2 kg-1]
   real :: I_Cp          ! 1.0 / C_p [C Q-1 ~> kg degC J-1]
-  real :: I_Rho0Squared ! 1.0 / rho_0^2 (Boussinesq only) [ R-2 ~> kg2 m-6]
+  real :: I_Rho0Squared ! 1.0 / rho_0^2 (Boussinesq only) [R-2 ~> m6 kg-2]
   logical :: do_any     ! True if there is more to be done on the current j-row.
   logical :: calc_diags ! True if diagnostic tendencies are needed.
   logical :: nonBous    ! If true, do not make the Boussinesq approximation.
diff --git a/src/parameterizations/vertical/MOM_internal_tide_input.F90 b/src/parameterizations/vertical/MOM_internal_tide_input.F90
index 2384844f6e..4bf0351039 100644
--- a/src/parameterizations/vertical/MOM_internal_tide_input.F90
+++ b/src/parameterizations/vertical/MOM_internal_tide_input.F90
@@ -551,13 +551,13 @@ subroutine int_tide_input_init(Time, G, GV, US, param_file, diag, CS, itide)
 
   do fr=1,num_freq ; do j=js,je ; do i=is,ie
     mask_itidal = 1.0
-    if (G%bathyT(i,j) + G%Z_ref < min_zbot_itides) mask_itidal = 0.0
+    if (G%meanSL(i,j) + G%bathyT(i,j) < min_zbot_itides) mask_itidal = 0.0
 
     CS%tideamp(i,j,fr) = CS%tideamp(i,j,fr) * mask_itidal * G%mask2dT(i,j)
 
     ! Restrict rms topo to a fraction (often 10 percent) of the column depth.
     if (max_frac_rough >= 0.0) &
-      itide%h2(i,j) = min((max_frac_rough*(G%bathyT(i,j)+G%Z_ref))**2, itide%h2(i,j))
+      itide%h2(i,j) = min((max_frac_rough * max(G%meanSL(i,j) + G%bathyT(i,j), 0.0))**2, itide%h2(i,j))
 
     ! Compute the fixed part of internal tidal forcing; units are [R Z4 H-1 T-2 ~> J m-2 or J m kg-1] here.
     CS%TKE_itidal_coef(i,j,fr) = 0.5*US%L_to_Z*kappa_h2_factor * GV%H_to_RZ * &
diff --git a/src/parameterizations/vertical/MOM_kappa_shear.F90 b/src/parameterizations/vertical/MOM_kappa_shear.F90
index da2c261ad9..9dfd509e8c 100644
--- a/src/parameterizations/vertical/MOM_kappa_shear.F90
+++ b/src/parameterizations/vertical/MOM_kappa_shear.F90
@@ -183,7 +183,7 @@ subroutine Calculate_kappa_shear(u_in, v_in, h, tv, p_surf, kappa_io, tke_io, &
     u0xdz, &    ! The initial zonal velocity times dz [H L T-1 ~> m2 s-1 or kg m-1 s-1]
     v0xdz, &    ! The initial meridional velocity times dz [H L T-1 ~> m2 s-1 or kg m-1 s-1]
     T0xdz, &    ! The initial temperature times thickness [C H ~> degC m or degC kg m-2] or if
-                ! temperature is not a state variable, the density times thickness [R H ~> kg m-2 or kg2 m-3]
+                ! temperature is not a state variable, the density times thickness [R H ~> kg m-2 or kg2 m-5]
     S0xdz       ! The initial salinity times dz [S H ~> ppt m or ppt kg m-2].
   real, dimension(SZK_(GV)+1) :: &
     kappa, &    ! The shear-driven diapycnal diffusivity at an interface [H Z T-1 ~> m2 s-1 or Pa s]
diff --git a/src/parameterizations/vertical/MOM_set_diffusivity.F90 b/src/parameterizations/vertical/MOM_set_diffusivity.F90
index caf0555d28..bebc693103 100644
--- a/src/parameterizations/vertical/MOM_set_diffusivity.F90
+++ b/src/parameterizations/vertical/MOM_set_diffusivity.F90
@@ -229,8 +229,7 @@ module MOM_set_diffusivity
 
   real, pointer, dimension(:,:,:) :: TKE_to_Kd => NULL()
                           !< conversion rate (~1.0 / (G_Earth + dRho_lay)) between TKE
-                          !! dissipated within a layer and Kd in that layer
-                          !! [H Z T-1 / H Z2 T-3 = T2 Z-1 ~> s2 m-1]
+                          !! dissipated within a layer and Kd in that layer [T2 Z-1 ~> s2 m-1]
 
 end type diffusivity_diags
 
@@ -307,8 +306,7 @@ subroutine set_diffusivity(u, v, h, u_h, v_h, tv, fluxes, optics, visc, dt, Kd_i
     prof_Froude_2d, & !< vertical profile for Froude drag [Z-1 ~> m-1]
     prof_slope_2d, & !< vertical profile for critical slopes [Z-1 ~> m-1]
     TKE_to_Kd     !< Conversion rate (~1.0 / (G_Earth + dRho_lay)) between
-                  !< TKE dissipated within a layer and Kd in that layer
-                  !< [H Z T-1 / H Z2 T-3 = T2 Z-1 ~> s2 m-1]
+                  !< TKE dissipated within a layer and Kd in that layer [T2 Z-1 ~> s2 m-1]
 
   real, dimension(SZI_(G),SZK_(GV)+1) :: &
     N2_int,   &   !< squared buoyancy frequency associated at interfaces [T-2 ~> s-2]
@@ -888,7 +886,7 @@ subroutine find_TKE_to_Kd(h, tv, dRho_int, N2_lay, j, dt, G, GV, US, CS, &
                                                           !! TKE dissipated within a layer and the
                                                           !! diapycnal diffusivity within that layer,
                                                           !! usually (~Rho_0 / (G_Earth * dRho_lay))
-                                                          !! [H Z T-1 / H Z2 T-3 = T2 Z-1 ~> s2 m-1]
+                                                          !! [T2 Z-1 ~> s2 m-1]
   real, dimension(SZI_(G),SZK_(GV)), intent(out)  :: maxTKE !< The energy required to for a layer to entrain to its
                                                           !! maximum realizable thickness [H Z2 T-3 ~> m3 s-3 or W m-2]
   integer, dimension(SZI_(G)),      intent(out)   :: kb   !< Index of lightest layer denser than the buffer
@@ -1382,7 +1380,7 @@ subroutine add_drag_diffusivity(h, u, v, tv, fluxes, visc, j, TKE_to_Kd, maxTKE,
                                                           !! TKE dissipated within a layer and the
                                                           !! diapycnal diffusivity within that layer,
                                                           !! usually (~Rho_0 / (G_Earth * dRho_lay))
-                                                          !! [H Z T-1 / H Z2 T-3 = T2 Z-1 ~> s2 m-1]
+                                                          !! [T2 Z-1 ~> s2 m-1]
   real, dimension(SZI_(G),SZK_(GV)), intent(in)   :: maxTKE !< The energy required to for a layer to entrain to its
                                                           !! maximum-realizable thickness [H Z2 T-3 ~> m3 s-3 or W m-2]
   integer, dimension(SZI_(G)),      intent(in)    :: kb   !< Index of lightest layer denser than the buffer
@@ -1805,7 +1803,7 @@ subroutine add_MLrad_diffusivity(dz, fluxes, tv, j, Kd_int, G, GV, US, CS, TKE_t
                                                             !! TKE dissipated within  a layer and the
                                                             !! diapycnal diffusivity witin that layer,
                                                             !! usually (~Rho_0 / (G_Earth * dRho_lay))
-                                                            !! [H Z T-1 / H Z2 T-3 = T2 Z-1 ~> s2 m-1]
+                                                            !! [T2 Z-1 ~> s2 m-1]
   real, dimension(SZI_(G),SZK_(GV)), &
                           optional, intent(inout) :: Kd_lay !< The diapycnal diffusivity in layers
                                                             !! [H Z T-1 ~> m2 s-1 or kg m-1 s-1].
diff --git a/src/parameterizations/vertical/MOM_set_viscosity.F90 b/src/parameterizations/vertical/MOM_set_viscosity.F90
index 6466b71dd5..e9e52ed1f0 100644
--- a/src/parameterizations/vertical/MOM_set_viscosity.F90
+++ b/src/parameterizations/vertical/MOM_set_viscosity.F90
@@ -75,6 +75,8 @@ module MOM_set_visc
                             !! actual velocity in the bottommost `HBBL`, depending
                             !! on whether linear_drag is true.
                             !! Runtime parameter `BOTTOMDRAGLAW`.
+  logical :: bottomdragmap  !< If true, apply the spatially varying drag coefficient (cdrag_2d)
+                            !! instead of the spatially uniform drag coefficient (cdrag).
   logical :: body_force_drag !< If true, the bottom stress is imposed as an explicit body force
                             !! applied over a fixed distance from the bottom, rather than as an
                             !! implicit calculation based on an enhanced near-bottom viscosity.
@@ -87,6 +89,12 @@ module MOM_set_visc
   real    :: Chan_drag_max_vol !< The maximum bottom boundary layer volume within which the
                             !! channel drag is applied, normalized by the full cell area,
                             !! or a negative value to apply no maximum [Z ~> m].
+  real    :: channel_break_depth !< When CHANNEL_DRAG is true, the bathymetric depth interpolated
+                            !! to the vorticity point is a combination of the harmonic mean of the
+                            !! adjacent velocity point depths below this depth [Z ~> m] and the
+                            !! arithmetic mean of the adjacent depths above it, to roughly mimic a
+                            !! continental shelf break profile.  The internal version of this depth
+                            !! uses the same offset (G%Z_ref) as the bathymetry.
   logical :: correct_BBL_bounds !< If true, uses the correct bounds on the BBL thickness and
                             !! viscosity so that the bottom layer feels the intended drag.
   logical :: RiNo_mix       !< If true, use Richardson number dependent mixing.
@@ -103,6 +111,10 @@ module MOM_set_visc
   real    :: omega_frac     !<   When setting the decay scale for turbulence, use this
                             !! fraction of the absolute rotation rate blended with the local
                             !! value of f, as sqrt((1-of)*f^2 + of*4*omega^2) [nondim]
+  real    :: tideampfac2    !< A factor to multiply by tideamp to convert to a mean ustar,
+                            !! accounts for conversion of amplitude to mean magnitude over
+                            !! a time average much longer than the tidal periods and for
+                            !! non-commuting conversion of mean tideamp to mean ustar**3 [nondim]
   logical :: concave_trigonometric_L  !< If true, use trigonometric expressions to determine the
                             !! fractional open interface lengths for concave topography.
   integer :: answer_date    !< The vintage of the order of arithmetic and expressions in the set
@@ -117,6 +129,8 @@ module MOM_set_visc
   type(diag_ctrl), pointer :: diag => NULL() !< A structure that is used to
                             !! regulate the timing of diagnostic output.
   ! Allocatable data arrays
+  real, allocatable, dimension(:,:) :: cdrag_u !< The spatially varying quadratic drag coefficient [nondim]
+  real, allocatable, dimension(:,:) :: cdrag_v !< The spatially varying quadratic drag coefficient [nondim]
   real, allocatable, dimension(:,:) :: tideamp !< RMS tidal amplitude at h points [Z T-1 ~> m s-1]
   ! Diagnostic arrays
   real, allocatable, dimension(:,:) :: bbl_u !< BBL mean U current [L T-1 ~> m s-1]
@@ -207,6 +221,7 @@ subroutine set_viscous_BBL(u, v, h, tv, visc, G, GV, US, CS, pbv)
   real :: ustarsq          ! 400 times the square of ustar, times
                            ! Rho0 divided by G_Earth and the conversion
                            ! from m to thickness units [H R ~> kg m-2 or kg2 m-5].
+  real :: cdrag            ! The drag coefficient [nondim].
   real :: cdrag_sqrt       ! Square root of the drag coefficient [nondim].
   real :: cdrag_sqrt_H     ! Square root of the drag coefficient, times a unit conversion factor
                            ! from lateral lengths to layer thicknesses [H L-1 ~> nondim or kg m-3].
@@ -242,7 +257,7 @@ subroutine set_viscous_BBL(u, v, h, tv, visc, G, GV, US, CS, pbv)
                            ! magnitudes [H L T-1 ~> m2 s-1 or kg m-1 s-1].
   real :: Thtot            ! Running sum of thickness times temperature [C H ~> degC m or degC kg m-2].
   real :: Shtot            ! Running sum of thickness times salinity [S H ~> ppt m or ppt kg m-2].
-  real :: SpV_htot         ! Running sum of thickness times specific volume [R-1 H ~> m4 kg-1 or m]
+  real :: SpV_htot         ! Running sum of thickness times specific volume [H R-1 ~> m4 kg-1 or m]
   real :: hweight          ! The thickness of a layer that is within Hbbl
                            ! of the bottom [H ~> m or kg m-2].
   real :: dzweight         ! The counterpart of hweight in height units [Z ~> m].
@@ -255,8 +270,11 @@ subroutine set_viscous_BBL(u, v, h, tv, visc, G, GV, US, CS, pbv)
   real :: p_ref(SZI_(G))   !   The pressure used to calculate the coordinate
                            ! density [R L2 T-2 ~> Pa] (usually set to 2e7 Pa = 2000 dbar).
 
-  real :: D_vel            ! The bottom depth at a velocity point [Z ~> m].
-  real :: Dp, Dm           ! The depths at the edges of a velocity cell [Z ~> m].
+  real :: D_vel            ! The bottom depth relative to the shelfbreak depth at a velocity point [Z ~> m].
+  real :: Dp, Dm           ! The bottom depths at the edges of a velocity cell relative to the
+                           ! shelfbreak depth [Z ~> m].
+  real :: D_vel_p, D_vel_m ! The bottom depths in adjacent velocity points relative to the
+                           ! shelfbreak depth [Z ~> m].
   real :: crv              ! crv is the curvature of the bottom depth across a
                            ! cell, times the cell width squared [Z ~> m].
   real :: slope            ! The absolute value of the bottom depth slope across
@@ -301,6 +319,7 @@ subroutine set_viscous_BBL(u, v, h, tv, visc, G, GV, US, CS, pbv)
   real :: h_bbl_fr         ! The fraction of the bottom boundary layer in a layer [nondim].
   real :: h_sum            ! The sum of the thicknesses of the layers below the one being
                            ! worked on [H ~> m or kg m-2].
+  real :: tideampfac2_x_0p5 ! tideampfac2 multiplied by the c-grid averaging factor of 0.5
   real, parameter :: C1_3 = 1.0/3.0, C1_6 = 1.0/6.0, C1_12 = 1.0/12.0 ! Rational constants [nondim]
   real :: tmp              ! A temporary variable, sometimes in [Z ~> m]
   logical :: use_BBL_EOS, do_i(SZIB_(G))
@@ -316,6 +335,7 @@ subroutine set_viscous_BBL(u, v, h, tv, visc, G, GV, US, CS, pbv)
   dz_neglect = GV%dZ_subroundoff
 
   Rho0x400_G = 400.0*(GV%H_to_RZ / GV%g_Earth_Z_T2)
+  tideampfac2_x_0p5 = CS%tideampfac2*0.5
 
   if (.not.CS%initialized) call MOM_error(FATAL,"MOM_set_viscosity(BBL): "//&
          "Module must be initialized before it is used.")
@@ -340,11 +360,13 @@ subroutine set_viscous_BBL(u, v, h, tv, visc, G, GV, US, CS, pbv)
   use_BBL_EOS = associated(tv%eqn_of_state) .and. CS%BBL_use_EOS
   OBC => CS%OBC
 
-  cdrag_sqrt = sqrt(CS%cdrag)
-  cdrag_sqrt_H = cdrag_sqrt * US%L_to_m * GV%m_to_H
-  cdrag_sqrt_H_RL = cdrag_sqrt * US%L_to_Z * GV%RZ_to_H
-  cdrag_L_to_H = CS%cdrag * US%L_to_m * GV%m_to_H
-  cdrag_RL_to_H = CS%cdrag * US%L_to_Z * GV%RZ_to_H
+  if (.not.CS%bottomdragmap) then
+    cdrag_sqrt = sqrt(CS%cdrag)
+    cdrag_sqrt_H = cdrag_sqrt * US%L_to_m * GV%m_to_H
+    cdrag_sqrt_H_RL = cdrag_sqrt * US%L_to_Z * GV%RZ_to_H
+    cdrag_L_to_H = CS%cdrag * US%L_to_m * GV%m_to_H
+    cdrag_RL_to_H = CS%cdrag * US%L_to_Z * GV%RZ_to_H
+  endif
   BBL_thick_max = G%Rad_Earth_L * US%L_to_Z
   K2 = max(nkmb+1, 2)
 
@@ -366,23 +388,23 @@ subroutine set_viscous_BBL(u, v, h, tv, visc, G, GV, US, CS, pbv)
 
   !$OMP parallel do default(shared)
   do J=js-1,je ; do i=is-1,ie+1
-    D_v(i,J) = 0.5*(G%bathyT(i,j) + G%bathyT(i,j+1)) + G%Z_ref
+    D_v(i,J) = 0.5*(G%bathyT(i,j) + G%bathyT(i,j+1))
     mask_v(i,J) = G%mask2dCv(i,J)
   enddo ; enddo
   !$OMP parallel do default(shared)
   do j=js-1,je+1 ; do I=is-1,ie
-    D_u(I,j) = 0.5*(G%bathyT(i,j) + G%bathyT(i+1,j)) + G%Z_ref
+    D_u(I,j) = 0.5*(G%bathyT(i,j) + G%bathyT(i+1,j))
     mask_u(I,j) = G%mask2dCu(I,j)
   enddo ; enddo
 
-  if (associated(OBC)) then
+  if (associated(OBC) .and. CS%Channel_drag) then
     ! Use a one-sided projection of bottom depths at OBC points.
     if (OBC%v_N_OBCs_on_PE) then
       Js_OBC = max(js-1, OBC%Js_v_N_obc) ; Je_OBC = min(je, OBC%Je_v_N_obc)
       is_OBC = max(is-1, OBC%is_v_N_obc) ; ie_OBC = min(ie+1, OBC%ie_v_N_obc)
       !$OMP parallel do default(shared)
       do J=Js_OBC,Je_OBC ; do i=is_OBC,ie_OBC
-        if (OBC%segnum_v(i,J) > 0) D_v(i,J) = G%bathyT(i,j) + G%Z_ref !  OBC_DIRECTION_N
+        if (OBC%segnum_v(i,J) > 0) D_v(i,J) = G%bathyT(i,j) !  OBC_DIRECTION_N
       enddo ; enddo
     endif
     if (OBC%v_S_OBCs_on_PE) then
@@ -390,7 +412,7 @@ subroutine set_viscous_BBL(u, v, h, tv, visc, G, GV, US, CS, pbv)
       is_OBC = max(is-1, OBC%is_v_S_obc) ; ie_OBC = min(ie+1, OBC%ie_v_S_obc)
       !$OMP parallel do default(shared)
       do J=Js_OBC,Je_OBC ; do i=is_OBC,ie_OBC
-        if (OBC%segnum_v(i,J) < 0) D_v(i,J) = G%bathyT(i,j+1) + G%Z_ref !  OBC_DIRECTION_S
+        if (OBC%segnum_v(i,J) < 0) D_v(i,J) = G%bathyT(i,j+1) !  OBC_DIRECTION_S
       enddo ; enddo
     endif
     if (OBC%u_E_OBCs_on_PE) then
@@ -398,7 +420,7 @@ subroutine set_viscous_BBL(u, v, h, tv, visc, G, GV, US, CS, pbv)
       Is_OBC = max(is-1, OBC%Is_u_E_obc) ; Ie_OBC = min(ie, OBC%Ie_u_E_obc)
       !$OMP parallel do default(shared)
       do j=js_OBC,je_OBC ; do I=Is_OBC,Ie_OBC
-        if (OBC%segnum_u(I,j) > 0) D_u(I,j) = G%bathyT(i,j) + G%Z_ref !  OBC_DIRECTION_E
+        if (OBC%segnum_u(I,j) > 0) D_u(I,j) = G%bathyT(i,j) !  OBC_DIRECTION_E
       enddo ; enddo
     endif
     if (OBC%u_W_OBCs_on_PE) then
@@ -406,12 +428,12 @@ subroutine set_viscous_BBL(u, v, h, tv, visc, G, GV, US, CS, pbv)
       Is_OBC = max(is-1, OBC%Is_u_W_obc) ; Ie_OBC = min(ie, OBC%Ie_u_W_obc)
       !$OMP parallel do default(shared)
       do j=js_OBC,je_OBC ; do I=Is_OBC,Ie_OBC
-        if (OBC%segnum_u(I,j) < 0) D_u(I,j) = G%bathyT(i+1,j) + G%Z_ref !  OBC_DIRECTION_W
+        if (OBC%segnum_u(I,j) < 0) D_u(I,j) = G%bathyT(i+1,j) !  OBC_DIRECTION_W
       enddo ; enddo
     endif
   endif
 
-  if (associated(OBC)) then ; do n=1,OBC%number_of_segments
+  if (associated(OBC) .and. CS%Channel_drag) then ; do n=1,OBC%number_of_segments
     ! Now project bottom depths across cell-corner points in the OBCs.  The two
     ! projections have to occur in sequence and can not be combined easily.
     if (.not. OBC%segment(n)%on_pe) cycle
@@ -608,10 +630,10 @@ subroutine set_viscous_BBL(u, v, h, tv, visc, G, GV, US, CS, pbv)
     ! Set the "back ground" friction velocity scale to either the tidal amplitude or place-holder constant
     if (CS%BBL_use_tidal_bg) then
       do i=is,ie ; if (do_i(i)) then ; if (m==1) then
-        u2_bg(I) = 0.5*( G%mask2dT(i,j)*(CS%tideamp(i,j)*CS%tideamp(i,j))+ &
+        u2_bg(I) = tideampfac2_x_0p5 * ( G%mask2dT(i,j)*(CS%tideamp(i,j)*CS%tideamp(i,j))+ &
                          G%mask2dT(i+1,j)*(CS%tideamp(i+1,j)*CS%tideamp(i+1,j)) )
       else
-        u2_bg(i) = 0.5*( G%mask2dT(i,j)*(CS%tideamp(i,j)*CS%tideamp(i,j))+ &
+        u2_bg(i) = tideampfac2_x_0p5 * ( G%mask2dT(i,j)*(CS%tideamp(i,j)*CS%tideamp(i,j))+ &
                          G%mask2dT(i,j+1)*(CS%tideamp(i,j+1)*CS%tideamp(i,j+1)) )
       endif ; endif ; enddo
     else
@@ -629,6 +651,16 @@ subroutine set_viscous_BBL(u, v, h, tv, visc, G, GV, US, CS, pbv)
         dztot_vel = 0.0 ; dzwtot = 0.0
         Thtot = 0.0 ; Shtot = 0.0 ; SpV_htot = 0.0
 
+        if (CS%bottomdragmap) then
+          if (m==1) then
+            cdrag_sqrt = sqrt(CS%cdrag_u(i,j))
+          else
+            cdrag_sqrt = sqrt(CS%cdrag_v(i,j))
+          endif
+          cdrag_sqrt_H = cdrag_sqrt * US%L_to_m * GV%m_to_H
+          cdrag_sqrt_H_RL = cdrag_sqrt * US%L_to_Z * GV%RZ_to_H
+        endif
+
         do k=nz,1,-1
 
           if (htot_vel>=CS%Hbbl) exit ! terminate the k loop
@@ -692,7 +724,17 @@ subroutine set_viscous_BBL(u, v, h, tv, visc, G, GV, US, CS, pbv)
 
       endif ; enddo
     else
-      do i=is,ie ; ustar(i) = cdrag_sqrt_H*CS%drag_bg_vel ; enddo
+      do i=is,ie
+        if (CS%bottomdragmap) then
+          if (m==1) then
+            cdrag_sqrt = sqrt(CS%cdrag_u(i,j))
+          else
+            cdrag_sqrt = sqrt(CS%cdrag_v(i,j))
+          endif
+          cdrag_sqrt_H = cdrag_sqrt * US%L_to_m * GV%m_to_H
+        endif
+        ustar(i) = cdrag_sqrt_H * CS%drag_bg_vel
+      enddo
     endif ! Not linear_drag
 
     if (use_BBL_EOS) then
@@ -723,6 +765,16 @@ subroutine set_viscous_BBL(u, v, h, tv, visc, G, GV, US, CS, pbv)
       htot = 0.0
       dztot = 0.0
 
+      if (CS%bottomdragmap) then
+        if (m==1) then
+          cdrag = CS%cdrag_u(i,j)
+        else
+          cdrag = CS%cdrag_v(i,j)
+        endif
+        cdrag_L_to_H = cdrag * US%L_to_m * GV%m_to_H
+        cdrag_RL_to_H = cdrag * US%L_to_Z * GV%RZ_to_H
+      endif
+
       ! Calculate the thickness of a stratification limited BBL ignoring rotation:
       !   h_N = Ci u* / N          (limit of KW99 eq. 2.20 for |f|->0)
       ! For layer mode, N^2 = g'/h. Since (Ci u*)^2 = (h_N N)^2 = h_N g' then
@@ -882,19 +934,29 @@ subroutine set_viscous_BBL(u, v, h, tv, visc, G, GV, US, CS, pbv)
           vol_below(K) = vol_below(K+1) + dz_vel(i,k)
         enddo
 
-        !### The harmonic mean edge depths here are not invariant to offsets!
+        ! Find the bathymetry at adjacent points relative to the shelf break.  For now this
+        ! shelf break depth is set with a global constant, but it could vary in space.
         if (m==1) then
-          D_vel = D_u(I,j)
-          tmp = G%mask2dCu(I,j+1) * D_u(I,j+1)
-          Dp = 2.0 * D_vel * tmp / (D_vel + tmp)
-          tmp = G%mask2dCu(I,j-1) * D_u(I,j-1)
-          Dm = 2.0 * D_vel * tmp / (D_vel + tmp)
+          D_vel = D_u(I,j) - CS%channel_break_depth
+          D_vel_p = G%mask2dCu(I,j+1) * (D_u(I,j+1) - CS%channel_break_depth)
+          D_vel_m = G%mask2dCu(I,j-1) * (D_u(I,j-1) - CS%channel_break_depth)
         else
-          D_vel = D_v(i,J)
-          tmp = G%mask2dCv(i+1,J) * D_v(i+1,J)
-          Dp = 2.0 * D_vel * tmp / (D_vel + tmp)
-          tmp = G%mask2dCv(i-1,J) * D_v(i-1,J)
-          Dm = 2.0 * D_vel * tmp / (D_vel + tmp)
+          D_vel = D_v(i,J) - CS%channel_break_depth
+          D_vel_p = G%mask2dCv(i+1,J) * (D_v(i+1,J) - CS%channel_break_depth)
+          D_vel_m = G%mask2dCv(i-1,J) * (D_v(i-1,J) - CS%channel_break_depth)
+        endif
+        ! This profile uses a harmonic mean bottom depth below some reference value to
+        ! roughly mimic the topographic shape at and beneath a continental shelf break.
+        ! Above this a simple arithmetic mean is used.
+        if ((D_vel > 0.0) .and. (D_vel_p > 0.0)) then
+          Dp = 2.0 * D_vel * D_vel_p / (D_vel + D_vel_p)
+        else  ! This is above the shelf-break, noting that D is positive downward.
+          Dp = 0.5 * (min(D_vel, 0.0) + min(D_vel_p, 0.0))
+        endif
+        if ((D_vel > 0.0) .and. (D_vel_m > 0.0)) then
+          Dm = 2.0 * D_vel * D_vel_m / (D_vel + D_vel_m)
+        else  ! This is above the shelf-break, noting that D is positive downward.
+          Dm = 0.5 * (min(D_vel, 0.0) + min(D_vel_m, 0.0))
         endif
         if (Dm > Dp) then ; tmp = Dp ; Dp = Dm ; Dm = tmp ; endif
         crv = 3.0*(Dp + Dm - 2.0*D_vel)
@@ -1940,7 +2002,7 @@ subroutine set_viscous_ML(u, v, h, tv, forces, visc, dt, G, GV, US, CS)
                 ! surface mixed layer [H C ~> m degC or kg degC m-2].
     Shtot, &    !   The integrated salt of layers that are within the
                 ! surface mixed layer [H S ~> m ppt or kg ppt m-2].
-    SpV_htot, & !   Running sum of thickness times specific volume [R-1 H ~> m4 kg-1 or m]
+    SpV_htot, & !   Running sum of thickness times specific volume [H R-1 ~> m4 kg-1 or m]
     Rhtot, &    !   The integrated density of layers that are within the surface mixed layer
                 ! [H R ~> kg m-2 or kg2 m-5].  Rhtot is only used if no
                 ! equation of state is used.
@@ -2330,7 +2392,7 @@ subroutine set_viscous_ML(u, v, h, tv, forces, visc, dt, G, GV, US, CS)
         ustarsq = Rho0x400_G * ustar(i)**2
         htot(i) = 0.0 ; dztot(i) = 0.0
         if (use_EOS) then
-          Thtot(i) = 0.0 ; Shtot(i) = 0.0
+          Thtot(i) = 0.0 ; Shtot(i) = 0.0 ; oldfn = 0.0
           do k=1,nz-1
             if (h_at_vel(i,k) <= 0.0) cycle
             T_Lay = 0.5 * (tv%T(i,j,k) + tv%T(i+1,j,k))
@@ -2609,7 +2671,7 @@ subroutine set_viscous_ML(u, v, h, tv, forces, visc, dt, G, GV, US, CS)
         htot(i) = 0.0
         dztot(i) = 0.0
         if (use_EOS) then
-          Thtot(i) = 0.0 ; Shtot(i) = 0.0
+          Thtot(i) = 0.0 ; Shtot(i) = 0.0 ; oldfn = 0.0
           do k=1,nz-1
             if (h_at_vel(i,k) <= 0.0) cycle
             T_Lay = 0.5 * (tv%T(i,j,k) + tv%T(i,j+1,k))
@@ -2899,8 +2961,15 @@ subroutine set_visc_init(Time, G, GV, US, param_file, diag, visc, CS, restart_CS
                              ! is used in place of the absolute value of the local Coriolis
                              ! parameter in the denominator of some expressions [nondim]
   real    :: Chan_max_thick_dflt ! The default value for CHANNEL_DRAG_MAX_THICK [Z ~> m]
-
-  integer :: i, j, k, is, ie, js, je
+  real    :: tideamp_factor  ! A factor to multiply by tideamp when converting to mean tidal magnitude [nondim]
+  real    :: shelfbreak_depth ! When CHANNEL_DRAG is true, the bathymetric depth interpolated
+                             ! to the vorticity point is a combination of the harmonic mean of the
+                             ! adjacent velocity point depths below this depth [Z ~> m] and the
+                             ! arithmetic mean of the adjacent depths above it, to roughly mimic a
+                             ! continental shelf break profile.
+  real, allocatable, dimension(:,:) :: cdrag_h !< The spatially varying quadratic drag coefficient [nondim]
+
+  integer :: i, j, is, ie, js, je
   integer :: isd, ied, jsd, jed, IsdB, IedB, JsdB, JedB, nz
   integer :: default_answer_date  ! The default setting for the various ANSWER_DATE flags.
   logical :: adiabatic, use_omega, MLE_use_PBL_MLD
@@ -2909,8 +2978,8 @@ subroutine set_visc_init(Time, G, GV, US, param_file, diag, visc, CS, restart_CS
                              ! isopycnal or stacked shallow water mode.
   logical :: use_temperature ! If true, temperature and salinity are used as state variables.
   logical :: use_EOS         ! If true, density calculated from T & S using an equation of state.
-  character(len=200) :: filename, tideamp_file ! Input file names or paths
-  character(len=80)  :: tideamp_var ! Input file variable names
+  character(len=200) :: filename, cdrag_file, tideamp_file ! Input file names or paths
+  character(len=80)  :: cdrag_var, tideamp_var ! Input file variable names
   ! This include declares and sets the variable "version".
 # include "version_variable.h"
   character(len=40)  :: mdl = "MOM_set_visc"  ! This module's name.
@@ -2952,8 +3021,18 @@ subroutine set_visc_init(Time, G, GV, US, param_file, diag, visc, CS, restart_CS
                  default=.false., do_not_log=.not.CS%bottomdraglaw)
   call get_param(param_file, mdl, "CHANNEL_DRAG", CS%Channel_drag, &
                  "If true, the bottom drag is exerted directly on each "//&
-                 "layer proportional to the fraction of the bottom it "//&
-                 "overlies.", default=.false.)
+                 "layer proportional to the fraction of the bottom it overlies.", &
+                 default=.false.)
+  call get_param(param_file, mdl, "CHANNEL_DRAG_SHELFBREAK_DEPTH", shelfbreak_depth, &
+                 "When CHANNEL_DRAG is true, the bathymetric depth interpolated to the "//&
+                 "vorticity point is a combination of the harmonic mean of the adjacent "//&
+                 "velocity point depths below this depth and the arithmetic mean of the "//&
+                 "depths above it, to roughly mimic a continental shelf break profile.  "//&
+                 "Setting this to exceed MAXIMUM_DEPTH leads to linear interpolation of "//&
+                 "the topography between velocity points.", &
+                 default=0.0, units="m", scale=US%m_to_Z, do_not_log=.not.CS%Channel_drag)
+  CS%channel_break_depth = shelfbreak_depth - G%Z_ref
+
   call get_param(param_file, mdl, "LINEAR_DRAG", CS%linear_drag, &
                  "If LINEAR_DRAG and BOTTOMDRAGLAW are defined the drag "//&
                  "law is cdrag*DRAG_BG_VEL*u.", default=.false.)
@@ -3026,6 +3105,16 @@ subroutine set_visc_init(Time, G, GV, US, param_file, diag, visc, CS, restart_CS
                  "CDRAG is the drag coefficient relating the magnitude of "//&
                  "the velocity field to the bottom stress. CDRAG is only "//&
                  "used if BOTTOMDRAGLAW is defined.", units="nondim", default=0.003)
+    call get_param(param_file, mdl, "CDRAG_MAP", CS%bottomdragmap, &
+                 "If true, apply a spatially varying scaling factor to CDRAG, "//&
+                 "specified by CDRAG_VAR in CDRAG_FILE.", default=.false.)
+    call get_param(param_file, mdl, "CDRAG_FILE", cdrag_file, &
+                 "The name of the file with the spatially varying bottom drag "//&
+                 "scaling factor.", default="", do_not_log=.not.CS%bottomdragmap)
+    call get_param(param_file, mdl, "CDRAG_VAR", cdrag_var, &
+                 "The name of the variable in CDRAG_FILE with the spatially "//&
+                 "varying bottom drag scaling factor at h points.", &
+                 default="", do_not_log=.not.CS%bottomdragmap)
     call get_param(param_file, mdl, "BBL_USE_TIDAL_BG", CS%BBL_use_tidal_bg, &
                  "Flag to use the tidal RMS amplitude in place of constant "//&
                  "background velocity for computing u* in the BBL. "//&
@@ -3043,6 +3132,17 @@ subroutine set_visc_init(Time, G, GV, US, param_file, diag, visc, CS, restart_CS
       ! nor dimensional testing in this mode. If we ever detect a dimensional sensitivity to
       ! this parameter, in this mode, then it means it is being used inappropriately.
       CS%drag_bg_vel = 1.e30
+      call get_param(param_file, mdl, "TIDEAMP_FACTOR", tideamp_factor, &
+                   "A parameter to multiply by tideamp when converting to ustar. "//&
+                   "It accounts for converting the amplitude to a mean magintude (approx 1/sqrt(2)) "//&
+                   "and possibly also for non-commuting averaging operators when converting to ustar**3. "//&
+                   "It is ignored if negative and uncapped so it can be greater than 1 if desired.",&
+                   units="nondim", default=-1.0)
+      if (tideamp_factor < 0.0) then
+        CS%tideampfac2 = 1.0
+      else
+        CS%tideampfac2 = tideamp_factor*tideamp_factor
+      endif
     else
       call get_param(param_file, mdl, "DRAG_BG_VEL", CS%drag_bg_vel, &
                    "DRAG_BG_VEL is either the assumed bottom velocity (with "//&
@@ -3171,6 +3271,27 @@ subroutine set_visc_init(Time, G, GV, US, param_file, diag, visc, CS, restart_CS
     if (CS%id_bbl_v>0) then
       allocate(CS%bbl_v(isd:ied,JsdB:JedB), source=0.0)
     endif
+    if (CS%bottomdragmap) then
+      if (len_trim(cdrag_file)==0 .or. len_trim(cdrag_var)==0) then
+        call MOM_error(FATAL,"CDRAG_FILE and CDRAG_VAR are required when using CDRAG_MAP.")
+      endif
+      allocate(cdrag_h(isd:ied,jsd:jed), source=0.0)
+      allocate(CS%cdrag_u(IsdB:IedB,jsd:jed), source=0.0)
+      allocate(CS%cdrag_v(isd:ied,JsdB:JedB), source=0.0)
+      filename = trim(CS%inputdir) // trim(cdrag_file)
+      call log_param(param_file, mdl, "INPUTDIR/CDRAG_FILE", filename)
+      call MOM_read_data(filename, cdrag_var, cdrag_h, G%domain, scale=CS%cdrag)
+      call pass_var(cdrag_h, G%domain)
+      do j=js,je ; do I=is-1,ie ; if (G%mask2dCu(I,j) > 0) then
+        CS%cdrag_u(I,j) = (G%mask2dT(i,j) * cdrag_h(i,j) + G%mask2dT(i+1,j) * cdrag_h(i+1,j)) / &
+                          (G%mask2dT(i,j) + G%mask2dT(i+1,j))
+      endif ; enddo ; enddo
+      do J=js-1,je ; do i=is,ie ; if (G%mask2dCv(i,J) > 0) then
+        CS%cdrag_v(i,J) = (G%mask2dT(i,j) * cdrag_h(i,j) + G%mask2dT(i,j+1) * cdrag_h(i,j+1)) / &
+                          (G%mask2dT(i,j) + G%mask2dT(i,j+1))
+      endif ; enddo ; enddo
+      deallocate(cdrag_h)
+    endif
     if (CS%BBL_use_tidal_bg) then
       allocate(CS%tideamp(isd:ied,jsd:jed), source=0.0)
       filename = trim(CS%inputdir) // trim(tideamp_file)
diff --git a/src/parameterizations/vertical/MOM_tidal_mixing.F90 b/src/parameterizations/vertical/MOM_tidal_mixing.F90
index 9a972e6e06..714a4efd50 100644
--- a/src/parameterizations/vertical/MOM_tidal_mixing.F90
+++ b/src/parameterizations/vertical/MOM_tidal_mixing.F90
@@ -507,16 +507,16 @@ logical function tidal_mixing_init(Time, G, GV, US, param_file, int_tide_CSp, di
                  units="nondim", default=0.1)
 
     do j=js,je ; do i=is,ie
-      if (G%bathyT(i,j)+G%Z_ref < CS%min_zbot_itides) CS%mask_itidal(i,j) = 0.0
+      if (max(G%meanSL(i,j) + G%bathyT(i,j), 0.0) < CS%min_zbot_itides) CS%mask_itidal(i,j) = 0.0
       CS%tideamp(i,j) = CS%tideamp(i,j) * CS%mask_itidal(i,j) * G%mask2dT(i,j)
 
       ! Restrict rms topo to a fraction (often 10 percent) of the column depth.
       if ((CS%tidal_answer_date < 20190101) .and. (max_frac_rough >= 0.0)) then
-        hamp = min(max_frac_rough*(G%bathyT(i,j)+G%Z_ref), sqrt(CS%h2(i,j)))
+        hamp = min(max_frac_rough * max(G%meanSL(i,j) + G%bathyT(i,j), 0.0), sqrt(CS%h2(i,j)))
         CS%h2(i,j) = hamp*hamp
       else
         if (max_frac_rough >= 0.0) &
-          CS%h2(i,j) = min((max_frac_rough*(G%bathyT(i,j)+G%Z_ref))**2, CS%h2(i,j))
+          CS%h2(i,j) = min((max_frac_rough * max(G%meanSL(i,j) + G%bathyT(i,j), 0.0))**2, CS%h2(i,j))
       endif
 
       utide = CS%tideamp(i,j)
@@ -713,7 +713,7 @@ subroutine calculate_tidal_mixing(dz, j, N2_bot, Rho_bot, N2_lay, N2_int, TKE_to
                                                             !! dissipated within a layer and the
                                                             !! diapycnal diffusivity within that layer,
                                                             !! usually (~Rho_0 / (G_Earth * dRho_lay))
-                                                            !! [H Z T-1 / H Z2 T-3 = T2 Z-1 ~> s2 m-1]
+                                                            !! [T2 Z-1 ~> s2 m-1]
   real, dimension(SZI_(G),SZK_(GV)), intent(in)   :: max_TKE !< The energy required for a layer to
                                                             !! entrain to its maximum realizable
                                                             !! thickness [H Z2 T-3 ~> m3 s-3 or W m-2]
@@ -1009,7 +1009,7 @@ subroutine add_int_tide_diffusivity(dz, j, N2_bot, Rho_bot, N2_lay, TKE_to_Kd, m
                                                              !! dissipated within a layer and the
                                                              !! diapycnal diffusivity within that layer,
                                                              !! usually (~Rho_0 / (G_Earth * dRho_lay))
-                                                             !! [H Z T-1 / H Z2 T-3 = T2 Z-1 ~> s2 m-1]
+                                                             !! [T2 Z-1 ~> s2 m-1]
   real, dimension(SZI_(G),SZK_(GV)), intent(in)    :: max_TKE !< The energy required for a layer
                                                              !! to entrain to its maximum realizable
                                                              !! thickness [H Z2 T-3 ~> m3 s-3 or W m-2]
diff --git a/src/parameterizations/vertical/MOM_vert_friction.F90 b/src/parameterizations/vertical/MOM_vert_friction.F90
index b4e75c56d2..e3161a8210 100644
--- a/src/parameterizations/vertical/MOM_vert_friction.F90
+++ b/src/parameterizations/vertical/MOM_vert_friction.F90
@@ -247,7 +247,7 @@ subroutine vertFPmix(ui, vi, uold, vold, hbl_h, h, forces, dt, lpost, Cemp_NL, G
   real :: Gat1, Gsig, dGdsig !< Shape parameters [nondim]
   real :: du, dv       !< Intermediate velocity differences [L T-1 ~> m s-1]
   real :: depth        !< Cumulative of thicknesses [H ~> m]
-  integer :: b, kbld, kp1, k, nz !< band and vertical indices
+  integer :: b, kp1, k, nz !< band and vertical indices
   integer :: i, j, is, ie, js, je, Isq, Ieq, Jsq, Jeq !< horizontal indices
 
   is = G%isc ; ie = G%iec; js = G%jsc; je = G%jec
@@ -1359,7 +1359,7 @@ subroutine vertvisc_coef(u, v, h, dz, forces, visc, tv, dt, G, GV, US, CS, OBC,
   logical :: do_any_shelf
   integer :: zi_dir
     ! A ternary logical indicating which thickness to use for finding z_clear.
-  integer :: i, j, k, is, ie, js, je, Isq, Ieq, Jsq, Jeq, nz, ij
+  integer :: i, j, k, is, ie, js, je, Isq, Ieq, Jsq, Jeq, nz
 
   is = G%isc ; ie = G%iec ; js = G%jsc ; je = G%jec
   Isq = G%IscB ; Ieq = G%IecB ; Jsq = G%JscB ; Jeq = G%JecB ; nz = GV%ke
diff --git a/src/tracer/MARBL_tracers.F90 b/src/tracer/MARBL_tracers.F90
index 847a174d36..ec9b2fc874 100644
--- a/src/tracer/MARBL_tracers.F90
+++ b/src/tracer/MARBL_tracers.F90
@@ -1308,7 +1308,7 @@ subroutine MARBL_tracers_column_physics(h_old, h_new, ea, eb, fluxes, dt, G, GV,
   real, dimension(SZI_(G),SZJ_(G)) :: flux_from_salt_flux ! Surface tracer flux from salt flux
                                                           ! [conc Z T-1 ~> conc m s-1].
   real, dimension(SZI_(G),SZJ_(G)) :: ref_mask ! Mask for 2D MARBL diags using ref_depth [1]
-  real, dimension(SZI_(G),SZJ_(G)) :: riv_flux_loc ! Local copy of CS%RIV_FLUXES*dt [mmol m-2 ~> conc H]
+  real, dimension(SZI_(G),SZJ_(G)) :: riv_flux_loc ! Local copy of CS%RIV_FLUXES*dt [conc H ~> mmol m-2]
   real, dimension(SZI_(G),SZJ_(G),SZK_(G)) :: h_work ! Used so that h can be modified [H ~> m or kg m-2]
   real, dimension(SZI_(G),SZJ_(G),SZK_(G)) :: bot_flux_to_tend  ! Conversion factor for bottom tlux -> tend
                                                                 ! [Z-1 ~> m-1]
diff --git a/src/tracer/MOM_CFC_cap.F90 b/src/tracer/MOM_CFC_cap.F90
index f9aa421f86..362497e869 100644
--- a/src/tracer/MOM_CFC_cap.F90
+++ b/src/tracer/MOM_CFC_cap.F90
@@ -516,7 +516,7 @@ subroutine CFC_cap_set_forcing(sfc_state, fluxes, day_start, day_interval, G, US
   !     Gas exchange/piston velocity parameter
   !---------------------------------------------------------------------
   ! From a = 0.251 cm/hr s^2/m^2 in Wannikhof 2014
-  !        = 6.97e-7 [m/s s^2/m^2] [Z T-1 T2 L-2] = [Z T L-2 ~> s / m]
+  !        = 6.97e-7 [m/s s^2/m^2] [Z T-1 T2 L-2] = [Z T L-2 ~> s m-1]
   kw_coeff = (US%m_to_Z*US%s_to_T*US%L_to_m**2) * 6.97e-7
 
   ! set unit conversion factors
@@ -719,7 +719,7 @@ end function CFC_cap_unit_tests
 logical function compare_values(verbose, test_name, calc, ans, limit)
   logical,             intent(in) :: verbose   !< If true, write results to stdout
   character(len=80),   intent(in) :: test_name !< Brief description of the unit test
-  real,                intent(in) :: calc      !< computed value in abitrary units [A]
+  real,                intent(in) :: calc      !< computed value in arbitrary units [A]
   real,                intent(in) :: ans       !< correct value [A]
   real,                intent(in) :: limit     !< value above which test fails [A]
 
diff --git a/src/tracer/MOM_tracer_advect.F90 b/src/tracer/MOM_tracer_advect.F90
index 6ca6614791..27db3f5caa 100644
--- a/src/tracer/MOM_tracer_advect.F90
+++ b/src/tracer/MOM_tracer_advect.F90
@@ -223,15 +223,15 @@ subroutine advect_tracer(h_end, uhtr, vhtr, OBC, dt, G, GV, US, CS, Reg, x_first
   !$OMP end parallel
 
   isv = is ; iev = ie ; jsv = js ; jev = je
+  nsten_halo = min(is - isd, ied - ie, js - jsd, jed - je) / stencil
 
   do itt=1,max_iter
 
     if (isv > is-stencil) then
       call do_group_pass(CS%pass_uhr_vhr_t_hprev, G%Domain, clock=id_clock_pass)
 
-      nsten_halo = min(is-isd,ied-ie,js-jsd,jed-je)/stencil
-      isv = is-nsten_halo*stencil ; jsv = js-nsten_halo*stencil
-      iev = ie+nsten_halo*stencil ; jev = je+nsten_halo*stencil
+      isv = is - nsten_halo * stencil ; jsv = js - nsten_halo * stencil
+      iev = ie + nsten_halo * stencil ; jev = je + nsten_halo * stencil
       ! Reevaluate domore_u & domore_v unless the valid range is the same size as
       ! before.  Also, do this if there is Strang splitting.
       if ((nsten_halo > 1) .or. (itt==1)) then
@@ -680,13 +680,12 @@ subroutine advect_x(Tr, hprev, uhr, uh_neglect, OBC, domore_u, ntr, Idt, &
 
     ! Update do_i so that nothing changes outside of the OBC (problem for interior OBCs only)
     if (associated(OBC)) then
-      if ((.not.OBC%exterior_OBC_bug) .and. (OBC%OBC_pe)) then
-        if (OBC%specified_u_BCs_exist_globally .or. OBC%open_u_BCs_exist_globally) then
-          do i=is,ie-1
-            if (OBC%segnum_u(I,j) > 0) do_i(i+1,j) = .false.  ! OBC_DIRECTION_E
-            if (OBC%segnum_u(I,j) < 0) do_i(i,j) = .false.    ! OBC_DIRECTION_W
-          enddo
-        endif
+      if ((.not.OBC%exterior_OBC_bug) .and. (OBC%OBC_pe) .and. &
+          (OBC%specified_u_BCs_exist_globally .or. OBC%open_u_BCs_exist_globally)) then
+        ! OBC_DIRECTION_E / OBC_DIRECTION_W on the west / east edge
+        do i=is,ie ; if ((OBC%segnum_u(I-1,j) > 0) .or. (OBC%segnum_u(I,j) < 0)) &
+          do_i(i,j) = .false.
+        enddo
       endif
     endif
 
@@ -1093,13 +1092,12 @@ subroutine advect_y(Tr, hprev, vhr, vh_neglect, OBC, domore_v, ntr, Idt, &
 
     ! Update do_i so that nothing changes outside of the OBC (problem for interior OBCs only)
     if (associated(OBC)) then
-      if ((OBC%exterior_OBC_bug .eqv. .false.) .and. (OBC%OBC_pe)) then
-        if (OBC%specified_v_BCs_exist_globally .or. OBC%open_v_BCs_exist_globally) then
-          do i=is,ie
-            if (OBC%segnum_v(i,J-1) > 0) do_i(i,j) = .false.  ! OBC_DIRECTION_N
-            if (OBC%segnum_v(i,J) < 0) do_i(i,j) = .false.  ! OBC_DIRECTION_S
-          enddo
-        endif
+      if ((.not.OBC%exterior_OBC_bug) .and. (OBC%OBC_pe) .and. &
+          (OBC%specified_v_BCs_exist_globally .or. OBC%open_v_BCs_exist_globally)) then
+        ! OBC_DIRECTION_N / OBC_DIRECTION_S on the south / north edge
+        do i=is,ie ; if ((OBC%segnum_v(i,J-1) > 0) .or. (OBC%segnum_v(i,J) < 0)) &
+          do_i(i,j) = .false.
+        enddo
       endif
     endif
 
diff --git a/src/tracer/MOM_tracer_flow_control.F90 b/src/tracer/MOM_tracer_flow_control.F90
index 2fce6325ad..efad2c4dcf 100644
--- a/src/tracer/MOM_tracer_flow_control.F90
+++ b/src/tracer/MOM_tracer_flow_control.F90
@@ -345,7 +345,7 @@ subroutine tracer_flow_control_init(restart, day, G, GV, US, h, param_file, diag
     call initialize_MARBL_tracers(restart, day, G, GV, US, h, param_file, diag, OBC, CS%MARBL_tracers_CSp, &
                                 sponge_CSp)
   if (CS%use_regional_dyes) &
-    call initialize_dye_tracer(restart, day, G, GV, h, diag, OBC, CS%dye_tracer_CSp, sponge_CSp, tv)
+    call initialize_dye_tracer(restart, day, G, GV, US, h, diag, OBC, CS%dye_tracer_CSp, sponge_CSp, tv)
   if (CS%use_oil) &
     call initialize_oil_tracer(restart, day, G, GV, US, h, diag, OBC, CS%oil_tracer_CSp, sponge_CSp)
   if (CS%use_advection_test_tracer) &
diff --git a/src/tracer/MOM_tracer_hor_diff.F90 b/src/tracer/MOM_tracer_hor_diff.F90
index 9a10826627..3e23483088 100644
--- a/src/tracer/MOM_tracer_hor_diff.F90
+++ b/src/tracer/MOM_tracer_hor_diff.F90
@@ -381,7 +381,7 @@ subroutine tracer_hordiff(h, dt, MEKE, VarMix, visc, G, GV, US, CS, Reg, tv, do_
     call cpu_clock_end(id_clock_sync)
     num_itts = max(1, ceiling(max_CFL - 4.0*EPSILON(max_CFL)))
     I_numitts = 1.0 / (real(num_itts))
-    if (CS%id_CFL > 0) call post_data(CS%id_CFL, CFL, CS%diag, mask=G%mask2dT)
+    if (CS%id_CFL > 0) call post_data(CS%id_CFL, CFL, CS%diag)
   elseif (CS%max_diff_CFL > 0.0) then
     num_itts = max(1, ceiling(CS%max_diff_CFL - 4.0*EPSILON(CS%max_diff_CFL)))
     I_numitts = 1.0 / (real(num_itts))
@@ -641,7 +641,6 @@ subroutine tracer_hordiff(h, dt, MEKE, VarMix, visc, G, GV, US, CS, Reg, tv, do_
         enddo
       enddo
     endif
-    !call post_data(CS%id_KhTr_u, Kh_u, CS%diag, is_static=.false., mask=G%mask2dCu)
     call post_data(CS%id_KhTr_u, Kh_u, CS%diag)
   endif
   if (CS%id_KhTr_v > 0) then
@@ -657,7 +656,6 @@ subroutine tracer_hordiff(h, dt, MEKE, VarMix, visc, G, GV, US, CS, Reg, tv, do_
         enddo
       enddo
     endif
-    !call post_data(CS%id_KhTr_v, Kh_v, CS%diag, is_static=.false., mask=G%mask2dCv)
     call post_data(CS%id_KhTr_v, Kh_v, CS%diag)
   endif
   if (CS%id_KhTr_h > 0) then
@@ -681,7 +679,6 @@ subroutine tracer_hordiff(h, dt, MEKE, VarMix, visc, G, GV, US, CS, Reg, tv, do_
         enddo
       endif
     enddo ; enddo
-    !call post_data(CS%id_KhTr_h, Kh_h, CS%diag, is_static=.false., mask=G%mask2dT)
     call post_data(CS%id_KhTr_h, Kh_h, CS%diag)
   endif
 
diff --git a/src/tracer/dye_example.F90 b/src/tracer/dye_example.F90
index c1146e19f9..bbd37ad26e 100644
--- a/src/tracer/dye_example.F90
+++ b/src/tracer/dye_example.F90
@@ -5,7 +5,7 @@ module regional_dyes
 
 use MOM_coms,               only : EFP_type
 use MOM_coupler_types,      only : set_coupler_type_data, atmos_ocn_coupler_flux
-use MOM_diag_mediator,      only : diag_ctrl
+use MOM_diag_mediator,      only : diag_ctrl, post_data, register_diag_field
 use MOM_error_handler,      only : MOM_error, FATAL, WARNING
 use MOM_file_parser,        only : get_param, log_param, log_version, param_file_type
 use MOM_forcing_type,       only : forcing
@@ -59,6 +59,8 @@ module regional_dyes
   integer, allocatable, dimension(:) :: ind_tr !< Indices returned by atmos_ocn_coupler_flux if it is used and the
                                                !! surface tracer concentrations are to be provided to the coupler.
 
+  integer, allocatable, dimension(:) :: id_tr_dia_diff !< Diagnostic IDs for vertical tracer fluxes (positive up)
+
   type(diag_ctrl), pointer :: diag => NULL() !< A structure that is used to
                                    !! regulate the timing of diagnostic output.
   type(MOM_restart_CS), pointer :: restart_CSp => NULL() !< A pointer to the restart control structure
@@ -116,6 +118,8 @@ function register_dye_tracer(HI, GV, US, param_file, CS, tr_Reg, restart_CS)
            CS%dye_source_maxdepth(CS%ntr))
   allocate(CS%ind_tr(CS%ntr))
   allocate(CS%tr_desc(CS%ntr))
+  allocate(CS%id_tr_dia_diff(CS%ntr))
+  CS%id_tr_dia_diff(:) = -1
 
   CS%dye_source_minlon(:) = -1.e30
   call get_param(param_file, mdl, "DYE_SOURCE_MINLON", CS%dye_source_minlon, &
@@ -204,12 +208,13 @@ end function register_dye_tracer
 
 !> This subroutine initializes the CS%ntr tracer fields in tr(:,:,:,:)
 !! and it sets up the tracer output.
-subroutine initialize_dye_tracer(restart, day, G, GV, h, diag, OBC, CS, sponge_CSp, tv)
+subroutine initialize_dye_tracer(restart, day, G, GV, US, h, diag, OBC, CS, sponge_CSp, tv)
   logical,                            intent(in) :: restart !< .true. if the fields have already been
                                                             !! read from a restart file.
   type(time_type), target,            intent(in) :: day  !< Time of the start of the run.
   type(ocean_grid_type),              intent(in) :: G    !< The ocean's grid structure
   type(verticalGrid_type),            intent(in) :: GV   !< The ocean's vertical grid structure
+  type(unit_scale_type),              intent(in) :: US   !< A dimensional unit scaling type
   real, dimension(SZI_(G),SZJ_(G),SZK_(GV)), intent(in) :: h !< Layer thicknesses [H ~> m or kg m-2]
   type(diag_ctrl), target,            intent(in) :: diag !< Structure used to regulate diagnostic output.
   type(ocean_OBC_type),               pointer    :: OBC  !< This open boundary condition type specifies
@@ -222,6 +227,7 @@ subroutine initialize_dye_tracer(restart, day, G, GV, h, diag, OBC, CS, sponge_C
   type(thermo_var_ptrs),              intent(in) :: tv   !< A structure pointing to various thermodynamic variables
 
   ! Local variables
+  character(len=64)  :: var_name, longname
   real    :: dz(SZI_(G),SZK_(GV)) ! Height change across layers [Z ~> m]
   real    :: z_bot    ! Height of the bottom of the layer relative to the sea surface [Z ~> m]
   real    :: z_center ! Height of the center of the layer relative to the sea surface [Z ~> m]
@@ -232,6 +238,14 @@ subroutine initialize_dye_tracer(restart, day, G, GV, h, diag, OBC, CS, sponge_C
 
   CS%diag => diag
 
+  ! Register vertical flux diagnostic
+  do m = 1, CS%ntr
+    write(var_name,'(A,I3.3,A)') "dye",m,"_dia_diff"
+    write(longname,'(A,I3.3,A)') "Vertical diffusive flux of dye ",m," (positive up)"
+    CS%id_tr_dia_diff(m) = register_diag_field('ocean_model', trim(var_name), &
+        diag%axesTi, day, trim(longname), 'conc H s-1', conversion=GV%H_to_MKS*US%s_to_T)
+  enddo
+
   ! Establish location of source
   do j=G%jsc,G%jec
     call thickness_to_dz(h, tv, dz, j, G, GV)
@@ -292,9 +306,12 @@ subroutine dye_tracer_column_physics(h_old, h_new, ea, eb, fluxes, dt, G, GV, US
 
   ! Local variables
   real, dimension(SZI_(G),SZJ_(G),SZK_(GV)) :: h_work ! Used so that h can be modified [H ~> m or kg m-2]
+  real, dimension(SZI_(G),SZJ_(G),SZK_(GV)+1) :: vert_flux ! Vertical tracer flux positive upward
+                                              !! [conc H T-1 ~> conc m s-1]
   real    :: dz(SZI_(G),SZK_(GV)) ! Height change across layers [Z ~> m]
   real    :: z_bot    ! Height of the bottom of the layer relative to the sea surface [Z ~> m]
   real    :: z_center ! Height of the center of the layer relative to the sea surface [Z ~> m]
+  real    :: Idt      ! Inverse of timestep [T-1 ~> s-1]
   integer :: i, j, k, is, ie, js, je, nz, m
 
   is = G%isc ; ie = G%iec ; js = G%jsc ; je = G%jec ; nz = GV%ke
@@ -302,6 +319,8 @@ subroutine dye_tracer_column_physics(h_old, h_new, ea, eb, fluxes, dt, G, GV, US
   if (.not.associated(CS)) return
   if (CS%ntr < 1) return
 
+  Idt = 1.0 / dt
+
   if (present(evap_CFL_limit) .and. present(minimum_forcing_depth)) then
     do m=1,CS%ntr
       do k=1,nz ; do j=js,je ; do i=is,ie
@@ -310,10 +329,34 @@ subroutine dye_tracer_column_physics(h_old, h_new, ea, eb, fluxes, dt, G, GV, US
       call applyTracerBoundaryFluxesInOut(G, GV, CS%tr(:,:,:,m), dt, fluxes, h_work, &
                                           evap_CFL_limit, minimum_forcing_depth)
       call tracer_vertdiff(h_work, ea, eb, dt, CS%tr(:,:,:,m), G, GV)
+
+      ! Calculate net vertical flux from entrainment
+      ! Net flux = upward component - downward component
+      ! Upward (from below): eb(k) * tr(k+1), Downward (from above): ea(k+1) * tr(k)
+      do K=2,nz ; do j=js,je ; do i=is,ie
+        vert_flux(i,j,K) = (eb(i,j,k-1) * CS%tr(i,j,k,m) - ea(i,j,k) * CS%tr(i,j,k-1,m)) * Idt
+      enddo ; enddo ; enddo
+      do j=js,je ; do i=is,ie ; vert_flux(i,j,1) = 0.0 ; vert_flux(i,j,nz+1) = 0.0 ; enddo ; enddo
+
+      ! Post diagnostic
+      if (CS%id_tr_dia_diff(m) > 0) &
+        call post_data(CS%id_tr_dia_diff(m), vert_flux, CS%diag)
     enddo
   else
     do m=1,CS%ntr
       call tracer_vertdiff(h_old, ea, eb, dt, CS%tr(:,:,:,m), G, GV)
+
+      ! Calculate net vertical flux from entrainment
+      ! Net flux = upward component - downward component
+      ! Upward (from below): eb(k) * tr(k+1), Downward (from above): ea(k+1) * tr(k)
+      do K=2,nz ; do j=js,je ; do i=is,ie
+        vert_flux(i,j,K) = (eb(i,j,k-1) * CS%tr(i,j,k,m) - ea(i,j,k) * CS%tr(i,j,k-1,m)) * Idt
+      enddo ; enddo ; enddo
+      do j=js,je ; do i=is,ie ; vert_flux(i,j,1) = 0.0 ; vert_flux(i,j,nz+1) = 0.0 ; enddo ; enddo
+
+      ! Post diagnostic
+      if (CS%id_tr_dia_diff(m) > 0) &
+        call post_data(CS%id_tr_dia_diff(m), vert_flux, CS%diag)
     enddo
   endif
 
diff --git a/src/user/MOM_controlled_forcing.F90 b/src/user/MOM_controlled_forcing.F90
index cd7389b961..2335ec73ba 100644
--- a/src/user/MOM_controlled_forcing.F90
+++ b/src/user/MOM_controlled_forcing.F90
@@ -296,7 +296,7 @@ subroutine apply_ctrl_forcing(SST_anom, SSS_anom, SSS_mean, virt_heat, virt_prec
     m_u2 = periodic_int(m_st - 3.0, CS%num_cycle)
     m_u3 = periodic_int(m_st - 2.0, CS%num_cycle)
 
-    ! These loops restore the units of the CS%avg variables to [degC] or [ppt]
+    ! These loops restore the units of the CS%avg variables to [C ~> degC] or [S ~> ppt]
     if (CS%avg_time(m_u1) > 0.0) then
       do j=js,je ; do i=is,ie
         CS%avg_SST_anom(i,j,m_u1) = CS%avg_SST_anom(i,j,m_u1) / CS%avg_time(m_u1)
diff --git a/src/user/SCM_CVMix_tests.F90 b/src/user/SCM_CVMix_tests.F90
index def4c59568..39ae327faa 100644
--- a/src/user/SCM_CVMix_tests.F90
+++ b/src/user/SCM_CVMix_tests.F90
@@ -251,7 +251,7 @@ subroutine SCM_CVMix_tests_buoyancy_forcing(sfc_state, fluxes, day, G, US, CS)
   IsdB = G%IsdB ; IedB = G%IedB ; JsdB = G%JsdB ; JedB = G%JedB
 
   if (CS%UseHeatFlux) then
-    ! Note CVMix test inputs give Heat flux in [Z C T-1 ~> m K/s]
+    ! Note CVMix test inputs give Heat flux in [Z C T-1 ~> m K s-1]
     ! therefore must convert to [Q R Z T-1 ~> W m-2] by multiplying
     ! by Rho0*Cp
     do J=Jsq,Jeq ; do i=is,ie