Merge branch 'initsnow' into release-v8.4.0 (PR #1438)

This merge fixes an issue in snow initialization over areas covered by seaice
in MPAS-A.

Snow water equivalent (as well as snow depth and snow cover) in the initial
conditions 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 merge corrects snow initialization, making it physically reasonable over
areas covered by seaice in winter.

* initsnow:
  Fix snow initialization over seaice points in MPAS-A

Author: mgduda

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

@@ -4539,9 +4539,6 @@ 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