Only use MARBL for Chl when using base_bio tracers

If MARBL is not configured to provide the base biotic tracers, then it will not
be able to provide chlorophyll. In that case, if CHL_FROM_FILE=False, MOM6
needs to get chlorophyll from the generic tracers.

src/tracer/MARBL_tracers.F90

@@ -540,7 +540,7 @@ end subroutine configure_MARBL_tracers
 
 !> This subroutine is used to register tracer fields and subroutines
 !! to be used with MOM.
-function register_MARBL_tracers(HI, GV, US, param_file, CS, tr_Reg, restart_CS)
+function register_MARBL_tracers(HI, GV, US, param_file, CS, tr_Reg, restart_CS, MARBL_computes_chl)
   type(hor_index_type),       intent(in) :: HI   !< A horizontal index type structure.
   type(verticalGrid_type),    intent(in) :: GV   !< The ocean's vertical grid structure
   type(unit_scale_type),      intent(in) :: US   !< A dimensional unit scaling type
@@ -550,6 +550,8 @@ function register_MARBL_tracers(HI, GV, US, param_file, CS, tr_Reg, restart_CS)
   type(tracer_registry_type), pointer    :: tr_Reg !< A pointer that is set to point to the control
                                                  !! structure for the tracer advection and diffusion module.
   type(MOM_restart_CS), target, intent(inout) :: restart_CS !< MOM restart control struct
+  logical,                      intent(out)   :: MARBL_computes_chl  !< If MARBL is computing chlorophyll, MOM
+                                                                     !! may use it to compute SW penetration
 
 ! Local variables
 ! This include declares and sets the variable "version".
@@ -581,6 +583,7 @@ function register_MARBL_tracers(HI, GV, US, param_file, CS, tr_Reg, restart_CS)
   allocate(CS)
 
   call configure_MARBL_tracers(GV, US, param_file, CS)
+  MARBL_computes_chl = CS%base_bio_on
 
   ! Read all relevant parameters and write them to the model log.
   call log_version(param_file, mdl, version, "")

src/tracer/MOM_tracer_flow_control.F90

@@ -100,6 +100,7 @@ module MOM_tracer_flow_control
   logical :: use_boundary_impulse_tracer = .false. !< If true, use the boundary impulse tracer package
   logical :: use_dyed_obc_tracer = .false.         !< If true, use the dyed OBC tracer package
   logical :: use_nw2_tracers = .false.             !< If true, use the NW2 tracer package
+  logical :: get_chl_from_MARBL = .false.          !< If true, use the MARBL-provided Chl for shortwave penetration
   !>@{ Pointers to the control strucures for the tracer packages
   type(USER_tracer_example_CS), pointer :: USER_tracer_example_CSp => NULL()
   type(DOME_tracer_CS), pointer :: DOME_tracer_CSp => NULL()
@@ -254,7 +255,7 @@ subroutine call_tracer_register(G, GV, US, param_file, CS, tr_Reg, restart_CS)
                               tr_Reg, restart_CS)
   if (CS%use_MARBL_tracers) CS%use_MARBL_tracers = &
     register_MARBL_tracers(G%HI, GV, US, param_file,  CS%MARBL_tracers_CSp, &
-                        tr_Reg, restart_CS)
+                        tr_Reg, restart_CS, CS%get_chl_from_MARBL)
   if (CS%use_regional_dyes) CS%use_regional_dyes = &
     register_dye_tracer(G%HI, GV, US, param_file, CS%dye_tracer_CSp, &
                         tr_Reg, restart_CS)
@@ -401,10 +402,10 @@ subroutine get_chl_from_model(Chl_array, G, GV, CS)
   type(tracer_flow_control_CS), pointer     :: CS        !< The control structure returned by a
                                                          !! previous call to call_tracer_register.
 
-  if (CS%use_MOM_generic_tracer) then
-    call MOM_generic_tracer_get('chl', 'field', Chl_array, CS%MOM_generic_tracer_CSp)
-  elseif (CS%use_MARBL_tracers) then
+  if (CS%get_chl_from_MARBL) then
     call MARBL_tracers_get('Chl', G, GV, Chl_array, CS%MARBL_tracers_CSp)
+  elseif (CS%use_MOM_generic_tracer) then
+    call MOM_generic_tracer_get('chl', 'field', Chl_array, CS%MOM_generic_tracer_CSp)
   else
     call MOM_error(FATAL, "get_chl_from_model was called in a configuration "// &
              "that is unable to provide a sensible model-based value.\n"// &