Merge branch 'proteanplanet/ocn/remove-dsshdx-filter' (PR #6067)

Removes sea surface height gradient filtering as a stealth option in E3SM This removes sea surface height gradient filtering from MPAS-Ocean coupling with MPAS-SeaIce, which is a stealth option in E3SM. This option was used in E3SM Version 1 to provide a temporary solution to "tiger stripes" in sea ice concentration associated with non-linear feedbacks between multiple bugs in the sea ice and ocean codes. The "tiger stripes" were reduced by time filtering sea surface height gradient passed from the ocean to the sea ice model through the coupler. The time filtering option was switched off in Version 2 of E3SM, but the code remained as a stealth option. This PR completely removes this stealth option for Version 3. The option should not be used in future. [NML] [BFB]
E3SM-Project · Dec 19, 2023 · d080e69 · d080e69
2 parents 524b754 + fbef231
commit d080e69
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Showing 6 changed files with 12 additions and 62 deletions.
diff --git a/components/mpas-ocean/bld/build-namelist b/components/mpas-ocean/bld/build-namelist
@@ -698,7 +698,6 @@ add_default($nl, 'config_flux_attenuation_coefficient_runoff');
 # Namelist group: coupling #
 ############################
 
-add_default($nl, 'config_ssh_grad_relax_timescale');
 if (($OCN_ICEBERG eq 'true') && ($OCN_FORCING eq 'active_atm')) {
 	add_default($nl, 'config_remove_AIS_coupler_runoff', 'val'=>".true.");
 } else {

diff --git a/components/mpas-ocean/bld/build-namelist-section b/components/mpas-ocean/bld/build-namelist-section
@@ -227,7 +227,6 @@ add_default($nl, 'config_flux_attenuation_coefficient_runoff');
 # Namelist group: coupling #
 ############################
 
-add_default($nl, 'config_ssh_grad_relax_timescale');
 add_default($nl, 'config_remove_AIS_coupler_runoff');
 
 ######################################

diff --git a/components/mpas-ocean/bld/namelist_files/namelist_defaults_mpaso.xml b/components/mpas-ocean/bld/namelist_files/namelist_defaults_mpaso.xml
@@ -289,7 +289,6 @@
 <config_flux_attenuation_coefficient_runoff>10.0</config_flux_attenuation_coefficient_runoff>
 
 <!-- coupling -->
-<config_ssh_grad_relax_timescale>0.0</config_ssh_grad_relax_timescale>
 <config_remove_AIS_coupler_runoff>.false.</config_remove_AIS_coupler_runoff>
 
 <!-- shortwaveRadiation -->

diff --git a/components/mpas-ocean/bld/namelist_files/namelist_definition_mpaso.xml b/components/mpas-ocean/bld/namelist_files/namelist_definition_mpaso.xml
@@ -1175,14 +1175,6 @@ Default: Defined in namelist_defaults.xml
 
 <!-- coupling -->
 
-<entry id="config_ssh_grad_relax_timescale" type="real"
-	category="coupling" group="coupling">
-Timescale for relaxation of the ssh gradient for coupling. A value of 0.0 (default) removes any relaxation and gives instantaneous response.
-
-Valid values: Any positive real number.
-Default: Defined in namelist_defaults.xml
-</entry>
-
 <entry id="config_remove_AIS_coupler_runoff" type="logical"
 	category="coupling" group="coupling">
 If true, solid and liquid runoff from the Antarctic Ice Sheet (below 60S latitude) coming from the coupled is zeroed in the coupler import routines.  To be used with data iceberg fluxes coming from the sea ice model.

diff --git a/components/mpas-ocean/driver/ocn_comp_mct.F b/components/mpas-ocean/driver/ocn_comp_mct.F
@@ -207,9 +207,8 @@ subroutine ocn_init_mct( EClock, cdata_o, x2o_o, o2x_o, NLFilename )!{{{
     logical, pointer :: config_use_surface_salinity_monthly_restoring
     character (len=StrKIND), pointer :: config_land_ice_flux_mode
 
-    ! Added for coupling interval initialization
+    ! ssh coupling interval initialization
     integer, pointer :: index_avgZonalSSHGradient, index_avgMeridionalSSHGradient
-    real (kind=RKIND), dimension(:),   pointer :: filteredSSHGradientZonal, filteredSSHGradientMeridional
     real (kind=RKIND), dimension(:,:), pointer :: avgSSHGradient
 
     interface
@@ -752,10 +751,6 @@ end subroutine xml_stream_get_attributes
           call mpas_pool_get_dimension(forcingPool, 'index_avgSSHGradientZonal', index_avgZonalSSHGradient)
           call mpas_pool_get_dimension(forcingPool, 'index_avgSSHGradientMeridional', index_avgMeridionalSSHGradient)
           call mpas_pool_get_array(forcingPool, 'avgSSHGradient', avgSSHGradient)
-          call mpas_pool_get_array(forcingPool, 'filteredSSHGradientZonal', filteredSSHGradientZonal)
-          call mpas_pool_get_array(forcingPool, 'filteredSSHGradientMeridional', filteredSSHGradientMeridional)
-          filteredSSHGradientZonal      = avgSSHGradient(index_avgZonalSSHGradient,     :)
-          filteredSSHGradientMeridional = avgSSHGradient(index_avgMeridionalSSHGradient, :)
           block_ptr => block_ptr % next
        end do
     endif
@@ -889,10 +884,7 @@ subroutine ocn_run_mct( EClock, cdata_o, x2o_o, o2x_o)!{{{
 
       ! Added for coupling interval initialization
       integer, pointer :: index_avgZonalSSHGradient, index_avgMeridionalSSHGradient
-      real (kind=RKIND), dimension(:),   pointer :: filteredSSHGradientZonal, filteredSSHGradientMeridional
       real (kind=RKIND), dimension(:,:), pointer :: avgSSHGradient
-      real (kind=RKIND), pointer :: config_ssh_grad_relax_timescale
-      real (kind=RKIND) :: timeFilterFactor
 
       iam = domain % dminfo % my_proc_id
 
@@ -1104,29 +1096,13 @@ subroutine ocn_run_mct( EClock, cdata_o, x2o_o, o2x_o)!{{{
          if (debugOn) call mpas_log_write('Completed timestep '//trim(timeStamp))
       end do
 
-      ! update coupled variables that get calculated on coupling intervals
-      ! NOTE: could be moved to subroutine
-      ! time filter ssh gradient
+      ! update coupled variables that are calculated on coupling intervals
       block_ptr => domain_ptr % blocklist
       do while(associated(block_ptr))
          call mpas_pool_get_subpool(block_ptr % structs, 'forcing', forcingPool)
          call mpas_pool_get_dimension(forcingPool, 'index_avgSSHGradientZonal', index_avgZonalSSHGradient)
          call mpas_pool_get_dimension(forcingPool, 'index_avgSSHGradientMeridional', index_avgMeridionalSSHGradient)
          call mpas_pool_get_array(forcingPool, 'avgSSHGradient', avgSSHGradient)
-         call mpas_pool_get_array(forcingPool, 'filteredSSHGradientZonal', filteredSSHGradientZonal)
-         call mpas_pool_get_array(forcingPool, 'filteredSSHGradientMeridional', filteredSSHGradientMeridional)
-         call mpas_pool_get_config(domain % configs, 'config_ssh_grad_relax_timescale', &
-                                                      config_ssh_grad_relax_timescale)
-         if (config_ssh_grad_relax_timescale < real(ocn_cpl_dt,RKIND)) then
-            filteredSSHGradientZonal = avgSSHGradient(index_avgZonalSSHGradient, :)
-            filteredSSHGradientMeridional = avgSSHGradient(index_avgMeridionalSSHGradient, :)
-         else
-            timeFilterFactor = real(ocn_cpl_dt,RKIND) / config_ssh_grad_relax_timescale
-            filteredSSHGradientZonal = filteredSSHGradientZonal * (1.0_RKIND - timeFilterFactor) + &
-                 avgSSHGradient(index_avgZonalSSHGradient, :) * timeFilterFactor
-            filteredSSHGradientMeridional = filteredSSHGradientMeridional * (1.0_RKIND - timeFilterFactor) + &
-                 avgSSHGradient(index_avgMeridionalSSHGradient, :) * timeFilterFactor
-         endif
          block_ptr => block_ptr % next
       end do
 
@@ -2545,7 +2521,8 @@ subroutine ocn_export_mct(o2x_o, errorCode)   !{{{
 
    integer :: i, n
    integer, pointer :: nCellsSolve, index_temperatureSurfaceValue, index_salinitySurfaceValue, &
-                       index_avgZonalSurfaceVelocity, index_avgMeridionalSurfaceVelocity
+                       index_avgZonalSurfaceVelocity, index_avgMeridionalSurfaceVelocity, &
+                       index_avgZonalSSHGradient, index_avgMeridionalSSHGradient
 
    type (block_type), pointer :: block_ptr
 
@@ -2561,7 +2538,6 @@ subroutine ocn_export_mct(o2x_o, errorCode)   !{{{
    integer, dimension(:), pointer :: landIceMask
 
    real (kind=RKIND), dimension(:), pointer :: seaIceEnergy, accumulatedFrazilIceMass, frazilSurfacePressure, &
-                                               filteredSSHGradientZonal, filteredSSHGradientMeridional, &
                                                avgTotalFreshWaterTemperatureFlux, &
                                                avgCO2_gas_flux, DMSFlux, surfaceUpwardCO2Flux, &
                                                avgOceanSurfaceDIC, &
@@ -2578,7 +2554,7 @@ subroutine ocn_export_mct(o2x_o, errorCode)   !{{{
                                                ssh
 
    real (kind=RKIND), dimension(:,:), pointer :: avgTracersSurfaceValue, avgSurfaceVelocity, &
-                                                 avgOceanSurfacePhytoC, &
+                                                 avgSSHGradient, avgOceanSurfacePhytoC, &
                                                  avgOceanSurfaceDOC, layerThickness
 
    real (kind=RKIND) :: surfaceFreezingTemp
@@ -2625,16 +2601,18 @@ subroutine ocn_export_mct(o2x_o, errorCode)   !{{{
      call mpas_pool_get_dimension(forcingPool, 'index_avgSalinitySurfaceValue', index_salinitySurfaceValue)
      call mpas_pool_get_dimension(forcingPool, 'index_avgSurfaceVelocityZonal', index_avgZonalSurfaceVelocity)
      call mpas_pool_get_dimension(forcingPool, 'index_avgSurfaceVelocityMeridional', index_avgMeridionalSurfaceVelocity)
+     call mpas_pool_get_dimension(forcingPool, 'index_avgSSHGradientZonal', index_avgZonalSSHGradient)
+     call mpas_pool_get_dimension(forcingPool, 'index_avgSSHGradientMeridional', index_avgMeridionalSSHGradient)
 
      call mpas_pool_get_array(statePool, 'ssh', ssh, 1)
      call mpas_pool_get_array(statePool, 'layerThickness', layerThickness, 1)
 
      call mpas_pool_get_array(forcingPool, 'landIceMask', landIceMask)
      call mpas_pool_get_array(forcingPool, 'avgTracersSurfaceValue', avgTracersSurfaceValue)
      call mpas_pool_get_array(forcingPool, 'avgSurfaceVelocity', avgSurfaceVelocity)
-     call mpas_pool_get_array(forcingPool, 'filteredSSHGradientZonal', filteredSSHGradientZonal)
-     call mpas_pool_get_array(forcingPool, 'filteredSSHGradientMeridional', filteredSSHGradientMeridional)
+     call mpas_pool_get_array(forcingPool, 'avgSSHGradient', avgSSHGradient)
      call mpas_pool_get_array(forcingPool, 'avgTotalFreshWaterTemperatureFlux', avgTotalFreshWaterTemperatureFlux)
+
      if ( frazilIceActive ) then
         call mpas_pool_get_array(forcingPool, 'seaIceEnergy', seaIceEnergy)
         call mpas_pool_get_array(forcingPool, 'frazilSurfacePressure', frazilSurfacePressure)
@@ -2687,15 +2665,11 @@ subroutine ocn_export_mct(o2x_o, errorCode)   !{{{
        o2x_o % rAttr(index_o2x_So_v, n) = avgSurfaceVelocity(index_avgMeridionalSurfaceVelocity, i)
 
        o2x_o % rAttr(index_o2x_So_ssh, n)  = ssh(i)
-       o2x_o % rAttr(index_o2x_So_dhdx, n) = filteredSSHGradientZonal(i)
-       o2x_o % rAttr(index_o2x_So_dhdy, n) = filteredSSHGradientMeridional(i)
+       o2x_o % rAttr(index_o2x_So_dhdx, n) = avgSSHGradient(index_avgZonalSSHGradient, i)
+       o2x_o % rAttr(index_o2x_So_dhdy, n) = avgSSHGradient(index_avgMeridionalSSHGradient, i)
 
        o2x_o % rAttr(index_o2x_Faoo_h2otemp, n) = avgTotalFreshWaterTemperatureFlux(i) * rho_sw * cp_sw
 
-       if (ocn_rof_two_way) then
-         o2x_o % rAttr(index_o2x_So_ssh, n)       = ssh(i)
-       end if
-
        if ( frazilIceActive ) then
           ! negative when frazil ice can be melted
           keepFrazil = .true.

diff --git a/components/mpas-ocean/src/Registry.xml b/components/mpas-ocean/src/Registry.xml
@@ -755,10 +755,6 @@
 		/>
 	</nml_record>
 	<nml_record name="coupling" mode="init;forward">
-		<nml_option name="config_ssh_grad_relax_timescale" type="real" default_value="0.0" units="seconds"
-					description="Timescale for relaxation of the ssh gradient for coupling. A value of 0.0 (default) removes any relaxation and gives instantaneous response."
-					possible_values="Any positive real number."
-		/>
 		<nml_option name="config_remove_AIS_coupler_runoff" type="logical" default_value=".false."
 					description="If true, solid and liquid runoff from the Antarctic Ice Sheet (below 60S latitude) coming from the coupled is zeroed in the coupler import routines.  To be used with data iceberg fluxes coming from the sea ice model."
 					possible_values=".true. or .false."
@@ -1930,8 +1926,7 @@
 			<var name="accumulatedLandIceHeat"/>
 			<var name="accumulatedLandIceFrazilMass"/>
 			<var name="frazilSurfacePressure"/>
-			<var name="filteredSSHGradientZonal"/>
-			<var name="filteredSSHGradientMeridional"/>
+			<var_array name="avgSSHGradient"/>
 			<var name="forcingGroupNames"/>
 			<var name="forcingGroupRestartTimes"/>
             <var name="gotmVertViscTopOfCell"/>
@@ -3679,14 +3674,6 @@
 				 description="Time averaged meridional gradient of SSH"
 			/>
 		</var_array>
-		<var name="filteredSSHGradientZonal" type="real" dimensions="nCells Time" units="1"
-			description="Time filtered zonal gradient of SSH"
-			packages="forwardMode;analysisMode"
-		/>
-		<var name="filteredSSHGradientMeridional" type="real" dimensions="nCells Time" units="1"
-			description="Time filtered meridional gradient of SSH"
-			packages="forwardMode;analysisMode"
-		/>
 		<var name="avgTotalFreshWaterTemperatureFlux" type="real" dimensions="nCells Time" units="C m s^-1"
 			 description="Sum of heat fluxes associated with water fluxes cell centers sent to coupler. Positive into the ocean."
 		/>