Fix snow initialization over seaice points in MPAS-A

This commit fixes an issue in snow initialization over the Arctic Ocean and
other areas covered by seaice.

Snow water equivalent (as well as snow depth and snow cover) in the initial
conditions of MPAS was set to zero over sea ice areas. This leads to a
significant warm bias of skintemp during model integration. When MPAS is
initialized in winter, the simulated conditions over polar regions become
physically unrealistic.

This commit corrects snow initialization, making it physically reasonable over
Arctic Ocean and other areas covered by seaice in winter.

Author: smileMchen

src/core_atmosphere/physics/mpas_atmphys_initialize_real.F

@@ -606,6 +606,7 @@ subroutine physics_init_seaice(mesh, input, dims, configs)
  real(kind=RKIND),pointer:: tsk_seaice_threshold
  real(kind=RKIND),dimension(:),pointer  :: vegfra
  real(kind=RKIND),dimension(:),pointer  :: seaice,snoalb,xice
+ real(kind=RKIND),dimension(:),pointer  :: snow, snowh, snowc
  real(kind=RKIND),dimension(:),pointer  :: skintemp,tmn,xland
  real(kind=RKIND),dimension(:,:),pointer:: tslb,smois,sh2o,smcrel
 
@@ -637,6 +638,9 @@ subroutine physics_init_seaice(mesh, input, dims, configs)
 
  call mpas_pool_get_array(input, 'seaice', seaice)
  call mpas_pool_get_array(input, 'xice', xice)
+ call mpas_pool_get_array(input, 'snowc', snowc)
+ call mpas_pool_get_array(input, 'snowh', snowh)
+ call mpas_pool_get_array(input, 'snow', snow)
  call mpas_pool_get_array(input, 'vegfra', vegfra)
 
  call mpas_pool_get_array(input, 'skintemp', skintemp)
@@ -699,6 +703,11 @@ subroutine physics_init_seaice(mesh, input, dims, configs)
           call mpas_log_write('$i $r $r $r', intArgs=(/iCell/), &
                                              realArgs=(/real(landmask(iCell),kind=RKIND),xland(iCell),xice(iCell)/))
        xice(iCell) = 0._RKIND
+       if(landmask(iCell) .eq. 0) then
+          snowc(iCell) = 0._RKIND  ! snow = 0 over water points
+          snowh(iCell) = 0._RKIND
+          snow(iCell) = 0._RKIND
+       endif
     endif
 
  enddo

src/core_init_atmosphere/mpas_init_atm_cases.F

@@ -4122,9 +4122,6 @@ subroutine init_atm_case_gfs(block, mesh, nCells, nEdges, nVertLevels, fg, state
                interp_list(2) = W_AVERAGE4
                interp_list(3) = 0
 
-               masked = 0
-               fillval = 0.0
-
                nInterpPoints = nCells
                latPoints => latCell
                lonPoints => lonCell