diff --git a/.gitmodules b/.gitmodules
index d253f6966..8244d5f8f 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -1,7 +1,7 @@
 [submodule "atmos_cubed_sphere"]
 	path = atmos_cubed_sphere
-	url = https://github.com/NOAA-EMC/GFDL_atmos_cubed_sphere
-	branch = dev/emc
+	url = https://github.com/jswhit2/GFDL_atmos_cubed_sphere
+	branch = iau_drymassfixer
 [submodule "ccpp/framework"]
 	path = ccpp/framework
 	url = https://github.com/NCAR/ccpp-framework
diff --git a/atmos_cubed_sphere b/atmos_cubed_sphere
index a56907a44..0c3016190 160000
--- a/atmos_cubed_sphere
+++ b/atmos_cubed_sphere
@@ -1 +1 @@
-Subproject commit a56907a44461c7151e0ba266e160c8f1a1685882
+Subproject commit 0c3016190c2851d3db54a7878279ec2869579f1b
diff --git a/gfsphysics/GFS_layer/GFS_typedefs.F90 b/gfsphysics/GFS_layer/GFS_typedefs.F90
index 09ab1da2d..8cef85314 100644
--- a/gfsphysics/GFS_layer/GFS_typedefs.F90
+++ b/gfsphysics/GFS_layer/GFS_typedefs.F90
@@ -1074,7 +1074,7 @@ module GFS_typedefs
     real(kind=kind_phys) :: iau_delthrs     ! iau time interval (to scale increments) in hours
     character(len=240)   :: iau_inc_files(7)! list of increment files
     real(kind=kind_phys) :: iaufhrs(7)      ! forecast hours associated with increment files
-    logical :: iau_filter_increments
+    logical :: iau_filter_increments, iau_drymassfixer
 
 #ifdef CCPP
     ! From physcons.F90, updated/set in control_initialize
@@ -3058,6 +3058,7 @@ subroutine control_initialize (Model, nlunit, fn_nml, me, master, &
     character(len=240)    :: iau_inc_files(7) = ''          !< list of increment files
     real(kind=kind_phys)  :: iaufhrs(7)       = -1          !< forecast hours associated with increment files
     logical  :: iau_filter_increments         = .false.     !< filter IAU increments
+    logical  :: iau_drymassfixer              = .false.     !< IAU dry mass fixer
 
 !--- debug flag
     logical              :: debug          = .false.
@@ -3170,6 +3171,7 @@ subroutine control_initialize (Model, nlunit, fn_nml, me, master, &
                                ca_sgs, ca_global,iseed_ca,ca_smooth,isppt_deep,nspinup,     &
                           !--- IAU
                                iau_delthrs,iaufhrs,iau_inc_files,iau_filter_increments,     &
+                               iau_drymassfixer,                                            &
                           !--- debug options
                                debug, pre_rad,                                              &
                           !--- parameter range for critical relative humidity
@@ -3650,6 +3652,7 @@ subroutine control_initialize (Model, nlunit, fn_nml, me, master, &
     Model%iau_inc_files   = iau_inc_files
     Model%iau_delthrs     = iau_delthrs
     Model%iau_filter_increments = iau_filter_increments
+    Model%iau_drymassfixer = iau_drymassfixer
     if(Model%me==0) print *,' model init,iaufhrs=',Model%iaufhrs
 
 !--- tracer handling