Export CO2 value to the land model via coupler

schemes/utilities/co2_diagnostic_export.F90

@@ -0,0 +1,31 @@
+! Export the diagnostic CO2 concentration to the surface coupler.
+module co2_diagnostic_export
+
+  implicit none
+  private
+
+  ! Public interfaces
+  public :: co2_diagnostic_export_run
+contains
+!> \section arg_table_co2_diagnostic_export_run Argument Table
+!! \htmlinclude co2_diagnostic_export_run.html
+subroutine co2_diagnostic_export_run(co2_vmr, co2diag, errmsg, errcode)
+   use ccpp_kinds,       only: kind_phys
+
+   ! Input arguments
+   real(kind_phys),  intent(in)  :: co2_vmr      ! Prescribed CO2 volume mixing ratio [mol mol-1]
+
+   ! Output arguments
+   real(kind_phys),  intent(out) :: co2diag(:)   ! Diagnostic CO2 concentration for coupler [ppmv]
+   character(len=*), intent(out) :: errmsg
+   integer,          intent(out) :: errcode
+
+   errmsg = ''
+   errcode = 0
+
+   ! mol/mol -> ppmv expected by the coupler. (chem_surfvals sets CO2VMR * 1e6)
+   co2diag(:) = co2_vmr * 1.0e6_kind_phys
+
+end subroutine co2_diagnostic_export_run
+
+end module co2_diagnostic_export

schemes/utilities/co2_diagnostic_export.meta

@@ -0,0 +1,31 @@
+[ccpp-table-properties]
+  name = co2_diagnostic_export
+  type = scheme
+
+[ccpp-arg-table]
+  name  = co2_diagnostic_export_run
+  type  = scheme
+[ co2_vmr ]
+  standard_name = prescribed_volume_mixing_ratio_of_co2
+  units = mol mol-1
+  type = real | kind = kind_phys
+  dimensions = ()
+  intent = in
+[ co2diag ]
+  standard_name = diagnostic_volume_mixing_ratio_of_co2_to_coupler
+  units = ppmv
+  type = real | kind = kind_phys
+  dimensions = (horizontal_loop_extent)
+  intent = out
+[ errmsg ]
+  standard_name = ccpp_error_message
+  units = none
+  type = character | kind = len=*
+  dimensions = ()
+  intent = out
+[ errcode ]
+  standard_name = ccpp_error_code
+  units = 1
+  type = integer
+  dimensions = ()
+  intent = out

suites/suite_cam4.xml

@@ -278,6 +278,7 @@
          of the "before_coupler" group. -->
     <scheme>calc_dry_air_ideal_gas_density</scheme>
     <scheme>set_surface_coupling_vars</scheme>
+    <scheme>co2_diagnostic_export</scheme>
 
   </group>
 

suites/suite_cam5.xml

@@ -160,6 +160,8 @@
          of the "before_coupler" group. -->
     <scheme>calc_dry_air_ideal_gas_density</scheme>
     <scheme>set_surface_coupling_vars</scheme>
+    <!-- Write CO2 concentration for surface model (Sa_co2diag) diagnostic CO2 mode -->
+    <scheme>co2_diagnostic_export</scheme>
 
   </group>
 

suites/suite_cam7.xml

@@ -81,7 +81,8 @@
          of the "before_coupler" group. -->
     <!-- UNCOMMENT ONCE ALL OTHER CAM7 SCHEMES ARE PRESENT -->
     <!-- <scheme>calc_dry_air_ideal_gas_density</scheme>
-    <scheme>set_surface_coupling_vars</scheme> -->
+    <scheme>set_surface_coupling_vars</scheme>
+    <scheme>co2_diagnostic_export</scheme> -->
 
   </group>