diff --git a/ndsl/constants.py b/ndsl/constants.py
index b7e91b18..946502df 100644
--- a/ndsl/constants.py
+++ b/ndsl/constants.py
@@ -126,6 +126,8 @@ class ConstantVersions(Enum):
     raise RuntimeError("Constant selector failed, bad code.")
 
 SECONDS_PER_DAY = Float(86400.0)
+SBC = 5.670400e-8
+"""Stefan-Boltzmann constant (W/m^2/K^4)"""
 DZ_MIN = Float(2.0)
 CV_AIR = CP_AIR - RDGAS  # Heat capacity of dry air at constant volume
 RDG = -RDGAS / GRAV
diff --git a/ndsl/namelist.py b/ndsl/namelist.py
index 304d9160..8df5c207 100644
--- a/ndsl/namelist.py
+++ b/ndsl/namelist.py
@@ -490,6 +490,8 @@ class Namelist:
     nf_omega: int = NamelistDefaults.nf_omega
     fv_sg_adj: int = NamelistDefaults.fv_sg_adj
     n_sponge: int = NamelistDefaults.n_sponge
+    daily_mean: bool = False
+    """Flag to replace cosz with daily mean value in physics"""
 
     @classmethod
     def from_f90nml(cls, namelist: f90nml.Namelist):