Minor cleanup related to pressure rescaling

  Minor refactoring of variables related to pressure rescaling and some cleanup
of comments.  All answers are bitwise identical.

src/core/MOM_dynamics_split_RK2.F90

@@ -305,7 +305,8 @@ subroutine step_MOM_dyn_split_RK2(u, v, h, tv, visc, Time_local, dt, forces, p_s
     ! u_old_rad_OBC and v_old_rad_OBC are the starting velocities, which are
     ! saved for use in the Flather open boundary condition code [L T-1 ~> m s-1].
 
-  real :: Pa_to_eta ! A factor that converts pressures to the units of eta.
+  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(:,:) :: &
     p_surf => NULL(), eta_PF_start => NULL(), &
     taux_bot => NULL(), tauy_bot => NULL(), &
@@ -412,11 +413,10 @@ subroutine step_MOM_dyn_split_RK2(u, v, h, tv, visc, Time_local, dt, forces, p_s
   call PressureForce(h, tv, CS%PFu, CS%PFv, G, GV, US, CS%PressureForce_CSp, &
                      CS%ALE_CSp, p_surf, CS%pbce, CS%eta_PF)
   if (dyn_p_surf) then
-    Pa_to_eta = US%RL2_T2_to_Pa / GV%H_to_Pa
+    pres_to_eta = 1.0 / (GV%g_Earth * GV%H_to_RZ)
     !$OMP parallel do default(shared)
     do j=Jsq,Jeq+1 ; do i=Isq,Ieq+1
-      eta_PF_start(i,j) = CS%eta_PF(i,j) - Pa_to_eta * &
-                          (p_surf_begin(i,j) - p_surf_end(i,j))
+      eta_PF_start(i,j) = CS%eta_PF(i,j) - pres_to_eta * (p_surf_begin(i,j) - p_surf_end(i,j))
     enddo ; enddo
   endif
   call cpu_clock_end(id_clock_pres)

src/parameterizations/vertical/MOM_energetic_PBL.F90

@@ -658,7 +658,7 @@ subroutine ePBL_column(h, u, v, T0, S0, dSV_dT, dSV_dS, TKE_forcing, B_flux, abs
   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 :: 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 ~> kg m-1 s-2 = Pa = J m-3].
+  real :: dPres     ! The hydrostatic pressure change across a layer [R Z2 T-2 ~> Pa = 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
@@ -805,7 +805,7 @@ subroutine ePBL_column(h, u, v, T0, S0, dSV_dT, dSV_dS, TKE_forcing, B_flux, abs
   pres_Z(1) = 0.0
   do k=1,nz
     dMass = GV%H_to_RZ * h(k)
-    dPres = US%L_to_Z**2 * GV%g_Earth * dMass  ! Equivalent to GV%H_to_Pa * h(k) with rescaling
+    dPres = US%L_to_Z**2 * GV%g_Earth * dMass
     dT_to_dPE(k) = (dMass * (pres_Z(K) + 0.5*dPres)) * dSV_dT(k)
     dS_to_dPE(k) = (dMass * (pres_Z(K) + 0.5*dPres)) * dSV_dS(k)
     dT_to_dColHt(k) = dMass * dSV_dT(k)