diff --git a/physics/module_nst_water_prop.f90 b/physics/module_nst_water_prop.f90
index 6a183da52..57f27f329 100644
--- a/physics/module_nst_water_prop.f90
+++ b/physics/module_nst_water_prop.f90
@@ -42,7 +42,7 @@ module module_nst_water_prop
   ! ------------------------------------------------------
 !>\ingroup gfs_nst_main_mod
 !! This subroutine computes thermal expansion coefficient (alpha)
-!! and saline contraction coefficient (beta). 
+!! and saline contraction coefficient (beta).
   subroutine rhocoef(t, s, rhoref, alpha, beta)
     ! ------------------------------------------------------
 
@@ -124,7 +124,7 @@ end subroutine density
   !======================
   !
 !>\ingroup gfs_nst_main_mod
-!! This subroutine computes the fraction of the solar radiation absorbed 
+!! This subroutine computes the fraction of the solar radiation absorbed
 !! by the depth z following Paulson and Simpson (1981) \cite paulson_and_simpson_1981 .
   elemental subroutine sw_ps_9b(z,fxp)
     !
@@ -159,7 +159,7 @@ end subroutine sw_ps_9b
   !======================
   !
 !>\ingroup gfs_nst_main_mod
-!! This subroutine 
+!! This subroutine
   elemental subroutine sw_ps_9b_aw(z,aw)
     !
     ! d(fw)/d(z) for 9-band
@@ -483,20 +483,16 @@ end subroutine sw_ohlmann_v1
   !
 
 !>\ingroup gfs_nst_main_mod
-function grv(lat)
-  real(kind=kind_phys) :: lat
-  real(kind=kind_phys) :: gamma,c1,c2,c3,c4,pi,phi,x
+function grv(x)
+  real(kind=kind_phys) :: x    !< sin(lat)
+  real(kind=kind_phys) :: gamma,c1,c2,c3,c4
   gamma=9.7803267715
   c1=0.0052790414
   c2=0.0000232718
   c3=0.0000001262
   c4=0.0000000007
-  pi=3.141593
 
-  phi=lat*pi/180
-  x=sin(phi)
-  grv=gamma*(1+(c1*x**2)+(c2*x**4)+(c3*x**6)+(c4*x**8))
-  !print *,'grav=',grv,lat
+  grv=gamma*(1.0+(c1*x**2)+(c2*x**4)+(c3*x**6)+(c4*x**8))
 end function grv
 
 !>\ingroup gfs_nst_main_mod