Use global_mass_integral in lateral_bdry_diff

  Use global_mass_integral for the debugging diagnostics of the tracer amounts
before and after diffusion in lateral_boundary_diffusion, and replaced a call to
write(*,*) with a call to MOM_mesg to actually write the message.  The
global_mass_integral uses reproducing sums, and is invariant to layout, while
MOM_mesg is preferable for output because it will allow us to more cleanly
control how output is handled and which processors do the writing.  All
solutions are bitwise identical, although some debugging output will change.

src/tracer/MOM_lateral_boundary_diffusion.F90

@@ -8,16 +8,17 @@ module MOM_lateral_boundary_diffusion
 use MOM_cpu_clock,             only : cpu_clock_id, cpu_clock_begin, cpu_clock_end
 use MOM_cpu_clock,             only : CLOCK_MODULE
 use MOM_checksums,             only : hchksum
-use MOM_domains,               only : pass_var, sum_across_PEs
+use MOM_domains,               only : pass_var
 use MOM_diag_mediator,         only : diag_ctrl, time_type
 use MOM_diag_mediator,         only : post_data, register_diag_field
 use MOM_diag_vkernels,         only : reintegrate_column
-use MOM_error_handler,         only : MOM_error, FATAL, is_root_pe
+use MOM_error_handler,         only : MOM_error, MOM_mesg, FATAL, is_root_pe
 use MOM_file_parser,           only : get_param, log_version, param_file_type
 use MOM_grid,                  only : ocean_grid_type
 use MOM_remapping,             only : remapping_CS, initialize_remapping
 use MOM_remapping,             only : extract_member_remapping_CS, remapping_core_h
 use MOM_remapping,             only : remappingSchemesDoc, remappingDefaultScheme
+use MOM_spatial_means,         only : global_mass_integral
 use MOM_tracer_registry,       only : tracer_registry_type, tracer_type
 use MOM_unit_scaling,          only : unit_scale_type
 use MOM_verticalGrid,          only : verticalGrid_type
@@ -169,13 +170,11 @@ subroutine lateral_boundary_diffusion(G, GV, US, h, Coef_x, Coef_y, dt, Reg, CS)
   real, dimension(SZK_(GV)) :: tracer_1d                    !< 1d-array used to remap tracer change to native grid
   real, dimension(SZI_(G),SZJ_(G),SZK_(GV))  :: tracer_old  !< local copy of the initial tracer concentration,
                                                             !! only used to compute tendencies.
-  real, dimension(SZI_(G),SZJ_(G))           :: tracer_int  !< integrated tracer before LBD is applied
-                                                            !! [conc H L2 ~> conc m3 or conc kg]
-  real, dimension(SZI_(G),SZJ_(G))           :: tracer_end  !< integrated tracer after LBD is applied.
-                                                            !! [conc H L2 ~> conc m3 or conc kg]
-  integer :: i, j, k, m   !< indices to loop over
+  real :: tracer_int_prev !< Globally integrated tracer before LBD is applied, in mks units [conc kg]
+  real :: tracer_int_end  !< Integrated tracer after LBD is applied, in mks units [conc kg]
   real    :: Idt          !< inverse of the time step [T-1 ~> s-1]
-  real    :: tmp1, tmp2   !< temporary variables [conc H L2 ~> conc m3 or conc kg]
+  character(len=256) :: mesg !< Message for error messages.
+  integer :: i, j, k, m   !< indices to loop over
 
   call cpu_clock_begin(id_clock_lbd)
   Idt = 1./dt
@@ -236,22 +235,11 @@ subroutine lateral_boundary_diffusion(G, GV, US, h, Coef_x, Coef_y, dt, Reg, CS)
 
     if (CS%debug) then
       call hchksum(tracer%t, "after LBD "//tracer%name,G%HI)
-      tracer_int(:,:) = 0.0; tracer_end(:,:) = 0.0
-      ! tracer (native grid) before and after LBD
-      do j=G%jsc,G%jec ; do i=G%isc,G%iec
-        do k=1,GV%ke
-          tracer_int(i,j) = tracer_int(i,j) + tracer_old(i,j,k) * &
-                    (h(i,j,k)*(G%mask2dT(i,j)*G%areaT(i,j)))
-          tracer_end(i,j) = tracer_end(i,j) + tracer%t(i,j,k) * &
-                      (h(i,j,k)*(G%mask2dT(i,j)*G%areaT(i,j)))
-        enddo
-      enddo; enddo
-
-      tmp1 = SUM(tracer_int)
-      tmp2 = SUM(tracer_end)
-      call sum_across_PEs(tmp1)
-      call sum_across_PEs(tmp2)
-      if (is_root_pe()) write(*,*)'Total '//tracer%name//' before/after LBD:', tmp1, tmp2
+      ! tracer (native grid) integrated tracer amounts before and after LBD
+      tracer_int_prev = global_mass_integral(h, G, GV, tracer_old)
+      tracer_int_end = global_mass_integral(h, G, GV, tracer%t)
+      write(mesg,*) 'Total '//tracer%name//' before/after LBD:', tracer_int_prev, tracer_int_end
+      call MOM_mesg(mesg)
     endif
 
     ! Post the tracer diagnostics