+Add MASS_WEIGHT_IN_PRESSURE_GRADIENT_TOP

Add MASS_WEIGHT_IN_PRESSURE_GRADIENT_TOP option for the top boundary, using top interface height, analogously to what is done near the bathymetry when MASS_WEIGHT_IN_PRESSURE_GRADIENT. The information from the is parameter is encoded in the MassWghtInterp value passed to the various int_density_... and int_spec_vol_... routines, so the routine interfaces do not change. For now this new bit of information about whether to do mass weighting near the surface under ice shelves is only used in int_density_dz_generic_plm. By default this new option is set to false and no answers are changed.
NOAA-GFDL · Sep 17, 2024 · 70a48e3 · 70a48e3
1 parent 5fc90eb
commit 70a48e3
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Showing 2 changed files with 41 additions and 5 deletions.
diff --git a/src/core/MOM_PressureForce_FV.F90 b/src/core/MOM_PressureForce_FV.F90
@@ -1028,6 +1028,7 @@ subroutine PressureForce_FV_init(Time, G, GV, US, param_file, diag, CS, SAL_CSp,
                            ! temperature variance [nondim]
   integer :: default_answer_date ! Global answer date
   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
   ! This include declares and sets the variable "version".
 # include "version_variable.h"
@@ -1072,9 +1073,14 @@ subroutine PressureForce_FV_init(Time, G, GV, US, param_file, diag, CS, SAL_CSp,
                  "If True, use the ALE algorithm (regridding/remapping). "//&
                  "If False, use the layered isopycnal algorithm.", default=.false. )
   call get_param(param_file, mdl, "MASS_WEIGHT_IN_PRESSURE_GRADIENT", useMassWghtInterp, &
-                 "If true, use mass weighting when interpolating T/S for "//&
-                 "integrals near the bathymetry in FV pressure gradient "//&
-                 "calculations.", default=.false.)
+                 "If true, use mass weighting when interpolating T/S for integrals "//&
+                 "near the bathymetry in FV pressure gradient calculations.", &
+                 default=.false.)
+  call get_param(param_file, mdl, "MASS_WEIGHT_IN_PRESSURE_GRADIENT_TOP", MassWghtInterpTop, &
+                 "If true and MASS_WEIGHT_IN_PRESSURE_GRADIENT is true, use mass weighting when "//&
+                 "interpolating T/S for integrals near the top of the water column in FV "//&
+                 "pressure gradient calculations. ", &
+                 default=.false.) !### Change Default to MASS_WEIGHT_IN_PRESSURE_GRADIENT?
   call get_param(param_file, mdl, "MASS_WEIGHT_IN_PGF_NONBOUS_BUG", MassWghtInterp_NonBous_bug, &
                  "If true, use a masking bug in non-Boussinesq calculations with mass weighting "//&
                  "when interpolating T/S for integrals near the bathymetry in FV pressure "//&
@@ -1083,8 +1089,11 @@ subroutine PressureForce_FV_init(Time, G, GV, US, param_file, diag, CS, SAL_CSp,
   CS%MassWghtInterp = 0
   if (useMassWghtInterp) &
     CS%MassWghtInterp = ibset(CS%MassWghtInterp, 0) ! Same as CS%MassWghtInterp + 1
+  if (MassWghtInterpTop) &
+    CS%MassWghtInterp = ibset(CS%MassWghtInterp, 1) ! Same as CS%MassWghtInterp + 2
   if ((.not.GV%Boussinesq) .and. MassWghtInterp_NonBous_bug) &
     CS%MassWghtInterp = ibset(CS%MassWghtInterp, 3) ! Same as CS%MassWghtInterp + 8
+
   call get_param(param_file, mdl, "USE_INACCURATE_PGF_RHO_ANOM", CS%use_inaccurate_pgf_rho_anom, &
                  "If true, use a form of the PGF that uses the reference density "//&
                  "in an inaccurate way. This is not recommended.", default=.false.)

diff --git a/src/core/MOM_density_integrals.F90 b/src/core/MOM_density_integrals.F90
@@ -471,10 +471,12 @@ subroutine int_density_dz_generic_plm(k, tv, T_t, T_b, S_t, S_b, e, rho_ref, &
   real :: dz_x(5,HI%iscB:HI%iecB) ! Layer thicknesses along an x-line of subgrid locations [Z ~> m]
   real :: dz_y(5,HI%isc:HI%iec)   ! Layer thicknesses along a y-line of subgrid locations [Z ~> m]
   real :: massWeightToggle          ! A non-dimensional toggle factor (0 or 1) [nondim]
+  real :: TopWeightToggle           ! A non-dimensional toggle factor (0 or 1) [nondim]
   real :: Ttl, Tbl, Ttr, Tbr        ! Temperatures at the velocity cell corners [C ~> degC]
   real :: Stl, Sbl, Str, Sbr        ! Salinities at the velocity cell corners [S ~> ppt]
   real :: z0pres(HI%isd:HI%ied,HI%jsd:HI%jed) ! The height at which the pressure is zero [Z ~> m]
   real :: hWght                     ! A topographically limited thickness weight [Z ~> m]
+  real :: hWghtTop                  ! An ice draft limited thickness weight [Z ~> m]
   real :: hL, hR                    ! Thicknesses to the left and right [Z ~> m]
   real :: iDenom                    ! The denominator of the thickness weight expressions [Z-2 ~> m-2]
   logical :: use_rho_ref ! Pass rho_ref to the equation of state for more accurate calculation
@@ -496,8 +498,11 @@ subroutine int_density_dz_generic_plm(k, tv, T_t, T_b, S_t, S_b, e, rho_ref, &
   else
     z0pres(:,:) = 0.0
   endif
-  massWeightToggle = 0.
-  if (present(MassWghtInterp)) then ; if (BTEST(MassWghtInterp, 0)) massWeightToggle = 1. ; endif
+  massWeightToggle = 0. ; TopWeightToggle = 0.
+  if (present(MassWghtInterp)) then
+    if (BTEST(MassWghtInterp, 0)) massWeightToggle = 1.
+    if (BTEST(MassWghtInterp, 1)) TopWeightToggle = 1.
+  endif
   use_rho_ref = .true.
   if (present(use_inaccurate_form)) use_rho_ref = .not. use_inaccurate_form
 
@@ -592,6 +597,17 @@ subroutine int_density_dz_generic_plm(k, tv, T_t, T_b, S_t, S_b, e, rho_ref, &
       ! this distance by the layer thickness to replicate other models.
       hWght = massWeightToggle * &
               max(0., -bathyT(i,j)-e(i+1,j,K), -bathyT(i+1,j)-e(i,j,K))
+      ! CY: The below code just uses top interface, which may be bad in high res open ocean
+      ! We want something like if (pa(i+1,k+1)<pa(i,1)) or (pa(i+1,1) <pa(i,k+1)) then...
+      ! but pressures are not passed through to this submodule, and tv just has surface press.
+      !if ((p(i+1,j,k+1)<p(i,j,1)).or.(tv%p(i+1,j,k+1)<tv%p(i,j,1))) then
+      hWghtTop = TopWeightToggle * &
+              max(0., e(i+1,j,K+1)-e(i,j,1), e(i,j,K+1)-e(i+1,j,1))
+      !else ! pressure criteria not activated
+      !  hWghtTop = 0.
+      !endif
+      ! Set it to be max of the bottom and top hWghts:
+      hWght = max(hWght, hWghtTop)
       if (hWght > 0.) then
         hL = (e(i,j,K) - e(i,j,K+1)) + dz_subroundoff
         hR = (e(i+1,j,K) - e(i+1,j,K+1)) + dz_subroundoff
@@ -688,6 +704,17 @@ subroutine int_density_dz_generic_plm(k, tv, T_t, T_b, S_t, S_b, e, rho_ref, &
     ! this distance by the layer thickness to replicate other models.
       hWght = massWeightToggle * &
               max(0., -bathyT(i,j)-e(i,j+1,K), -bathyT(i,j+1)-e(i,j,K))
+      ! CY: The below code just uses top interface, which may be bad in high res open ocean
+      ! We want something like if (pa(j+1,k+1)<pa(j,1)) or (pa(j+1,1) <pa(i,j,k+1)) then...
+      ! but pressures are not passed through to this submodule, and tv just has surface press.
+      !if ((p(i,j+1,k+1)<p(i,j,1)).or.(tv%p(i,j+1,k+1)<tv%p(i,j,1))) then
+      hWghtTop = TopWeightToggle * &
+              max(0., e(i,j+1,K+1)-e(i,j,1), e(i,j,K+1)-e(i,j+1,1))
+      !else ! pressure criteria not activated
+      !  hWghtTop = 0.
+      !endif
+      ! Set it to be max of the bottom and top hWghts:
+      hWght = max(hWght, hWghtTop)
       if (hWght > 0.) then
         hL = (e(i,j,K) - e(i,j,K+1)) + dz_subroundoff
         hR = (e(i,j+1,K) - e(i,j+1,K+1)) + dz_subroundoff