Wire up Sl_ddvel (gas dry-dep coupling) and cam_in%dstflx (Fall_flxdst) to CMEPS via nuopc

src/cpl/nuopc/atm_import_export.F90

@@ -57,17 +57,25 @@ module atm_import_export
   subroutine read_surface_fields_namelists()
 
     use shr_drydep_mod    , only : shr_drydep_readnl
+    use shr_drydep_mod    , only : shr_drydep_list => drydep_list
     use shr_megan_mod     , only : shr_megan_readnl
     use shr_fire_emis_mod , only : shr_fire_emis_readnl
     use shr_carma_mod     , only : shr_carma_readnl
     use shr_ndep_mod      , only : shr_ndep_readnl
     use shr_lightning_coupling_mod, only : shr_lightning_coupling_readnl
+    use drydep_coupling   , only : drydep_coupling_set_nflds, drydep_coupling_set_list
 
     character(len=*), parameter :: nl_file_name = 'drv_flds_in'
 
     ! read mediator fields options
     call shr_ndep_readnl(nl_file_name, ndep_nflds)
     call shr_drydep_readnl(nl_file_name, drydep_nflds)
+    ! Mirror the dry deposition field count and species names for physics;
+    ! registry fields dimensioned by the count are allocated later, during
+    ! physics initialization. The list order is the Sl_ddvel coupler index
+    ! contract with the land model.
+    call drydep_coupling_set_nflds(drydep_nflds)
+    call drydep_coupling_set_list(shr_drydep_list(1:drydep_nflds))
     call shr_megan_readnl(nl_file_name, megan_nflds)
     call shr_fire_emis_readnl(nl_file_name, emis_nflds)
     call shr_carma_readnl(nl_file_name, carma_fields)
@@ -647,19 +655,6 @@ subroutine import_fields( gcomp, cam_in, restart_init, rc)
        end if
     end if
 
-    ! dry deposition fluxes from land
-    call state_getfldptr(importState, 'Fall_flxdst', fldptr2d=fldptr2d, exists=exists, rc=rc)
-    if (ChkErr(rc,__LINE__,u_FILE_u)) return
-    if (exists) then
-       if ( associated(cam_in%dstflx) ) then
-          do i = 1, columns_on_task
-             do n = 1, size(fldptr2d, dim=1)
-                cam_in%dstflx(i,n) = fldptr2d(n,i) * med2mod_areacor(i)
-             end do
-          end do
-       end if
-    end if
-
     ! MEGAN VOC emis fluxes from land
     call state_getfldptr(importState, 'Fall_voc', fldptr2d=fldptr2d, exists=exists, rc=rc)
     if (ChkErr(rc,__LINE__,u_FILE_u)) return
@@ -693,9 +688,6 @@ subroutine import_fields( gcomp, cam_in, restart_init, rc)
     end if
 #endif
 
-#if 0
-! Ignoring depvel for now as it has a problematic second dimension (number of dry deposited species)
-! and it was determined that it probably will not be used in CAM-SIMA for some time
     ! dry dep velocities
     call state_getfldptr(importState, 'Sl_ddvel', fldptr2d=fldptr2d, exists=exists, rc=rc)
     if (ChkErr(rc,__LINE__,u_FILE_u)) return
@@ -706,7 +698,17 @@ subroutine import_fields( gcomp, cam_in, restart_init, rc)
           end do
        end do
     end if
-#endif
+
+    ! dust emission fluxes from land
+    call state_getfldptr(importState, 'Fall_flxdst', fldptr2d=fldptr2d, exists=exists, rc=rc)
+    if (ChkErr(rc,__LINE__,u_FILE_u)) return
+    if (exists) then
+       do i = 1, columns_on_task
+          do n = 1, size(fldptr2d, dim=1)
+             cam_in%dstflx(i,n) = fldptr2d(n,i) * med2mod_areacor(i)
+          end do
+       end do
+    end if
 
 #if 0
 ! Commented out until water isotopes or carbon cycle fluxes are implemented in CAM-SIMA

src/data/registry.xml

@@ -22,6 +22,7 @@
   <metadata_file>$SRCROOT/src/physics/utils/physics_grid.meta</metadata_file>
   <metadata_file>$SRCROOT/src/physics/utils/radiation_namelist.meta</metadata_file>
   <metadata_file>$SRCROOT/src/physics/utils/cam_constituents.meta</metadata_file>
+  <metadata_file>$SRCROOT/src/physics/utils/drydep_coupling.meta</metadata_file>
   <metadata_file>$SRCROOT/src/physics/utils/tropopause_climo_read.meta</metadata_file>
   <metadata_file>$SRCROOT/src/physics/utils/gravity_wave_drag_ridge_read.meta</metadata_file>
   <metadata_file>$SRCROOT/src/data/air_composition.meta</metadata_file>
@@ -751,14 +752,22 @@
 
     <!-- data_flux_fuel is being intentionally ignored as it will only be needed for the online carbon cycle -->
     <!-- data_flux_ocn is being intentionally ignored as it will only be needed for the online carbon cycle -->
-    <!-- depvel (dry_deposition_velocity_from_coupler) is being intentionally ignored as one of the dimensions is problematic
-         and it was determined that it probably will not be used in CAM-SIMA for some time -->
+
+    <!-- CLM computes and sends Sl_ddvel in cm/s; gas dry deposition
+         consumes it as-is in the Wesely land-type merge. -->
+    <variable local_name="depvel"
+              standard_name="dry_deposition_velocity_from_coupler"
+              units="cm s-1" type="real" kind="kind_phys"
+              allocatable="allocatable">
+      <dimensions>horizontal_dimension number_of_dry_deposition_species</dimensions>
+      <initial_value>0.0_kind_phys</initial_value>
+    </variable>
 
     <variable local_name="dstflx"
               standard_name="surface_upward_dust_fluxes_from_coupler"
               units="kg m-2 s-1" type="real" kind="kind_phys"
               allocatable="allocatable">
-      <dimensions>horizontal_dimension</dimensions>
+      <dimensions>horizontal_dimension dust_size_bin_dimension</dimensions>
       <initial_value>0.0_kind_phys</initial_value>
       <ic_file_input_names>dstflx cam_in_dstflx</ic_file_input_names>
     </variable>
@@ -1349,6 +1358,7 @@
        <data>surface_albedo_due_to_uv_and_vis_diffuse_from_coupler</data>
        <data>surface_albedo_due_to_uv_and_vis_direct_from_coupler</data>
        <data>surface_upward_ccpp_constituent_fluxes_from_coupler</data>
+       <data>dry_deposition_velocity_from_coupler</data>
        <data>surface_upward_dust_fluxes_from_coupler</data>
        <data>co2_flux_from_land_from_coupler</data>
        <data>co2_flux_from_ocean_from_coupler</data>
@@ -1490,6 +1500,18 @@
       <ic_file_input_names>pbuf_VPWP_CLUBB_GW</ic_file_input_names>
     </variable>
 
+    <!-- Aerosol model properties -->
+    <variable local_name="ndust"
+              standard_name="dust_size_bin_dimension"
+              units="count" type="integer" allocatable="parameter">
+      <long_name>number of dust size bins used in aerosol model</long_name>
+      <initial_value>4</initial_value>
+      <!-- this is not runtime configurable, and
+           not even easily compile-time configurable, because the assumption that
+           there are four dust bins is deeply embedded in the microphysics and
+           coupling to the land model (see dstdry1/2/3/4, dstwet1/2/3/4) -->
+    </variable>
+
     <!-- Gravity wave variables - need to be kept in the CAM registry -->
     <variable local_name="kvt"
               standard_name="molecular_kinematic_temperature_conductivity_at_interfaces"

src/physics/utils/drydep_coupling.F90

@@ -0,0 +1,39 @@
+module drydep_coupling
+
+   implicit none
+   private
+
+   public :: drydep_coupling_set_nflds
+   public :: drydep_coupling_set_list
+
+   !> \section arg_table_drydep_coupling  Argument Table
+   !! \htmlinclude drydep_coupling.html
+   ! Number of gas species with land-computed dry deposition velocities
+   ! received through the coupler field Sl_ddvel. The authoritative value
+   ! is owned by shr_drydep_mod (CMEPS) and set by shr_drydep_readnl during
+   ! the NUOPC advertise phase; the cap mirrors it here, before physics
+   ! initialization allocates registry fields dimensioned by it.
+   integer, public, protected :: n_drydep = 0
+
+   ! Species names of the drv_flds_in drydep_list, in list order. The list
+   ! order is the Sl_ddvel coupler index contract with the land model, so
+   ! it cannot be reordered or trimmed atm-side. Mirrored by the cap along
+   ! with the count; consumed by gas_drydep_ccpp at init (no metadata
+   ! entry: character arrays are use-associated, not capgen-passed).
+   character(len=32), allocatable, public, protected :: drydep_list(:)
+
+contains
+
+   subroutine drydep_coupling_set_nflds(n_drydep_in)
+      integer, intent(in) :: n_drydep_in
+
+      n_drydep = n_drydep_in
+   end subroutine drydep_coupling_set_nflds
+
+   subroutine drydep_coupling_set_list(drydep_list_in)
+      character(len=*), intent(in) :: drydep_list_in(:)
+
+      drydep_list = drydep_list_in
+   end subroutine drydep_coupling_set_list
+
+end module drydep_coupling

src/physics/utils/drydep_coupling.meta

@@ -0,0 +1,13 @@
+[ccpp-table-properties]
+  name = drydep_coupling
+  type = module
+
+[ccpp-arg-table]
+  name  = drydep_coupling
+  type  = module
+[ n_drydep ]
+  standard_name = number_of_dry_deposition_species
+  units = count
+  type = integer
+  dimensions = ()
+  protected = True