Update LBM flux names and fix posting of 2d diags

The 2d diagnostics associated with the lateral boundary mixing were
occuring outside the `if (CS%id_lbm_dfx_2d)` statements and were
thus leading to segfaults if the diagnostic was not requested.

Additionally the array variable names were refactored to be consistent
with the `id_` names and the diagnostic names.

src/tracer/MOM_lateral_boundary_mixing.F90

@@ -222,16 +222,16 @@ subroutine lateral_boundary_mixing(G, GV, US, h, Coef_x, Coef_y, dt, Reg, CS)
       do k=1,GV%ke; do j=G%jsc,G%jec; do I=G%isc-1,G%iec
         uwork_2d(I,j) = uwork_2d(I,j) + uFlx(I,j,k)
       enddo; enddo; enddo
+      call post_data(tracer%id_lbm_dfx_2d, uwork_2d, CS%diag)
     endif
-    call post_data(tracer%id_lbm_dfx_2d, uwork_2d, CS%diag)
 
     if (tracer%id_lbm_dfy_2d>0) then
       vwork_2d(:,:) = 0.
       do k=1,GV%ke; do J=G%jsc-1,G%jec; do i=G%isc,G%iec
         vwork_2d(i,J) = vwork_2d(i,J) + vFlx(i,J,k)
       enddo; enddo; enddo
+      call post_data(tracer%id_lbm_dfy_2d, vwork_2d, CS%diag)
     endif
-    call post_data(tracer%id_lbm_dfy_2d, vwork_2d, CS%diag)
   enddo
 
 end subroutine lateral_boundary_mixing

src/tracer/MOM_tracer_registry.F90

@@ -56,13 +56,13 @@ module MOM_tracer_registry
                                                               !! [conc H m2 s-1 ~> conc m3 s-1 or conc kg s-1]
   real, dimension(:,:,:), pointer :: df_y           => NULL() !< diagnostic array for y-diffusive tracer flux
                                                               !! [conc H m2 s-1 ~> conc m3 s-1 or conc kg s-1]
-  real, dimension(:,:,:), pointer :: lbm_df_x       => NULL() !< diagnostic array for x-diffusive tracer flux
+  real, dimension(:,:,:), pointer :: lbm_dfx       => NULL() !< diagnostic array for x-diffusive tracer flux
                                                               !! [conc H m2 s-1 ~> conc m3 s-1 or conc kg s-1]
-  real, dimension(:,:,:), pointer :: lbm_df_y       => NULL() !< diagnostic array for y-diffusive tracer flux
+  real, dimension(:,:,:), pointer :: lbm_dfy       => NULL() !< diagnostic array for y-diffusive tracer flux
                                                               !! [conc H m2 s-1 ~> conc m3 s-1 or conc kg s-1]
-  real, dimension(:,:), pointer :: lbm_df_x_2d       => NULL() !< diagnostic array for x-diffusive tracer flux
+  real, dimension(:,:), pointer :: lbm_dfx_2d       => NULL() !< diagnostic array for x-diffusive tracer flux
                                                               !! [conc H m2 s-1 ~> conc m3 s-1 or conc kg s-1]
-  real, dimension(:,:), pointer :: lbm_df_y_2d       => NULL() !< diagnostic array for y-diffusive tracer flux
+  real, dimension(:,:), pointer :: lbm_dfy_2d       => NULL() !< diagnostic array for y-diffusive tracer flux
                                                               !! [conc H m2 s-1 ~> conc m3 s-1 or conc kg s-1]
   real, dimension(:,:), pointer :: lbm_bulk_df_x       => NULL() !< diagnostic array for x-diffusive tracer flux
                                                               !! [conc H m2 s-1 ~> conc m3 s-1 or conc kg s-1]
@@ -458,10 +458,10 @@ subroutine register_tracer_diagnostics(Reg, h, Time, diag, G, GV, use_ALE)
     if (Tr%id_ady > 0) call safe_alloc_ptr(Tr%ad_y,isd,ied,JsdB,JedB,nz)
     if (Tr%id_dfx > 0) call safe_alloc_ptr(Tr%df_x,IsdB,IedB,jsd,jed,nz)
     if (Tr%id_dfy > 0) call safe_alloc_ptr(Tr%df_y,isd,ied,JsdB,JedB,nz)
-    if (Tr%id_lbm_dfx > 0) call safe_alloc_ptr(Tr%lbm_df_x,IsdB,IedB,jsd,jed,nz)
-    if (Tr%id_lbm_dfy > 0) call safe_alloc_ptr(Tr%lbm_df_y,isd,ied,JsdB,JedB,nz)
-    if (Tr%id_lbm_dfx_2d > 0) call safe_alloc_ptr(Tr%lbm_df_x_2d,IsdB,IedB,jsd,jed)
-    if (Tr%id_lbm_dfy_2d > 0) call safe_alloc_ptr(Tr%lbm_df_y_2d,isd,ied,JsdB,JedB)
+    if (Tr%id_lbm_dfx > 0) call safe_alloc_ptr(Tr%lbm_dfx,IsdB,IedB,jsd,jed,nz)
+    if (Tr%id_lbm_dfy > 0) call safe_alloc_ptr(Tr%lbm_dfy,isd,ied,JsdB,JedB,nz)
+    if (Tr%id_lbm_dfx_2d > 0) call safe_alloc_ptr(Tr%lbm_dfx_2d,IsdB,IedB,jsd,jed)
+    if (Tr%id_lbm_dfy_2d > 0) call safe_alloc_ptr(Tr%lbm_dfy_2d,isd,ied,JsdB,JedB)
 
     Tr%id_adx_2d = register_diag_field("ocean_model", trim(shortnm)//"_adx_2d", &
         diag%axesCu1, Time, &