+Add the runtime parameter REMAPPING_ANSWER_DATE

  Added the new runtime parameter REMAPPING_ANSWER_DATE, which takes precedence
over the older parameter REMAPPING_2018_ANSWERS.  There are 11 files with
get_param calls for this new parameter.  Also started logging the value of
DEFAULT_ANSWER_DATE.  All answers are bitwise identical, but there are new
entries in the MOM_parameter_doc.all files.

src/ALE/MOM_ALE.F90

@@ -94,7 +94,7 @@ module MOM_ALE
   integer :: answer_date    !< The vintage of the expressions and order of arithmetic to use for
                             !! remapping. Values below 20190101 result in the use of older, less
                             !! accurate expressions that were in use at the end of 2018.  Higher
-                            !! values result inthe use of more robust and accurate forms of
+                            !! values result in the use of more robust and accurate forms of
                             !! mathematically equivalent expressions.
 
   logical :: debug   !< If true, write verbose checksums for debugging purposes.
@@ -226,19 +226,25 @@ subroutine ALE_init( param_file, GV, US, max_depth, CS)
                  "extrapolated instead of piecewise constant", default=.false.)
   call get_param(param_file, mdl, "DEFAULT_ANSWER_DATE", default_answer_date, &
                  "This sets the default value for the various _ANSWER_DATE parameters.", &
-                 default=99991231, do_not_log=.true.)
+                 default=99991231)
   call get_param(param_file, mdl, "DEFAULT_2018_ANSWERS", default_2018_answers, &
                  "This sets the default value for the various _2018_ANSWERS parameters.", &
                  default=(default_answer_date<20190101))
   call get_param(param_file, mdl, "REMAPPING_2018_ANSWERS", answers_2018, &
                  "If true, use the order of arithmetic and expressions that recover the "//&
                  "answers from the end of 2018.  Otherwise, use updated and more robust "//&
                  "forms of the same expressions.", default=default_2018_answers)
-  if (answers_2018) then
-    CS%answer_date = 20181231
-  else
-    CS%answer_date = 20190101
-  endif
+  ! Revise inconsistent default answer dates for remapping.
+  if (answers_2018 .and. (default_answer_date >= 20190101)) default_answer_date = 20181231
+  if (.not.answers_2018 .and. (default_answer_date < 20190101)) default_answer_date = 20190101
+  call get_param(param_file, mdl, "REMAPPING_ANSWER_DATE", CS%answer_date, &
+                 "The vintage of the expressions and order of arithmetic to use for remapping.  "//&
+                 "Values below 20190101 result in the use of older, less accurate expressions "//&
+                 "that were in use at the end of 2018.  Higher values result in the use of more "//&
+                 "robust and accurate forms of mathematically equivalent expressions.  "//&
+                 "If both REMAPPING_2018_ANSWERS and REMAPPING_ANSWER_DATE are specified, the "//&
+                 "latter takes precedence.", default=default_answer_date)
+
   call initialize_remapping( CS%remapCS, string, &
                              boundary_extrapolation=remap_boundary_extrap, &
                              check_reconstruction=check_reconstruction, &

src/ALE/MOM_regridding.F90

@@ -208,6 +208,7 @@ subroutine initialize_regridding(CS, GV, US, max_depth, param_file, mdl, coord_m
   integer :: default_answer_date  ! The default setting for the various ANSWER_DATE flags.
   logical :: default_2018_answers ! The default setting for the various 2018_ANSWERS flags.
   logical :: remap_answers_2018
+  integer :: remap_answer_date    ! The vintage of the remapping expressions to use.
   real :: filt_len, strat_tol, tmpReal, P_Ref
   real :: maximum_depth ! The maximum depth of the ocean [m] (not in Z).
   real :: dz_fixed_sfc, Rho_avg_depth, nlay_sfc_int
@@ -269,15 +270,25 @@ subroutine initialize_regridding(CS, GV, US, max_depth, param_file, mdl, coord_m
 
     call get_param(param_file, mdl, "DEFAULT_ANSWER_DATE", default_answer_date, &
                  "This sets the default value for the various _ANSWER_DATE parameters.", &
-                 default=99991231, do_not_log=.true.)
+                 default=99991231)
     call get_param(param_file, mdl, "DEFAULT_2018_ANSWERS", default_2018_answers, &
                  "This sets the default value for the various _2018_ANSWERS parameters.", &
                  default=(default_answer_date<20190101))
     call get_param(param_file, mdl, "REMAPPING_2018_ANSWERS", remap_answers_2018, &
                  "If true, use the order of arithmetic and expressions that recover the "//&
                  "answers from the end of 2018.  Otherwise, use updated and more robust "//&
                  "forms of the same expressions.", default=default_2018_answers)
-    call set_regrid_params(CS, remap_answers_2018=remap_answers_2018)
+    ! Revise inconsistent default answer dates for remapping.
+    if (remap_answers_2018 .and. (default_answer_date >= 20190101)) default_answer_date = 20181231
+    if (.not.remap_answers_2018 .and. (default_answer_date < 20190101)) default_answer_date = 20190101
+    call get_param(param_file, mdl, "REMAPPING_ANSWER_DATE", remap_answer_date, &
+                 "The vintage of the expressions and order of arithmetic to use for remapping.  "//&
+                 "Values below 20190101 result in the use of older, less accurate expressions "//&
+                 "that were in use at the end of 2018.  Higher values result in the use of more "//&
+                 "robust and accurate forms of mathematically equivalent expressions.  "//&
+                 "If both REMAPPING_2018_ANSWERS and REMAPPING_ANSWER_DATE are specified, the "//&
+                 "latter takes precedence.", default=default_answer_date)
+    call set_regrid_params(CS, remap_answer_date=remap_answer_date)
   endif
 
   if (main_parameters .and. coord_is_state_dependent) then

src/core/MOM_open_boundary.F90

@@ -625,19 +625,24 @@ subroutine open_boundary_config(G, US, param_file, OBC)
           "round off.", default=.false.,do_not_log=.true.)
     call get_param(param_file, mdl, "DEFAULT_ANSWER_DATE", default_answer_date, &
                  "This sets the default value for the various _ANSWER_DATE parameters.", &
-                 default=99991231, do_not_log=.true.)
+                 default=99991231)
     call get_param(param_file, mdl, "DEFAULT_2018_ANSWERS", default_2018_answers, &
                  "This sets the default value for the various _2018_ANSWERS parameters.", &
                  default=(default_answer_date<20190101))
     call get_param(param_file, mdl, "REMAPPING_2018_ANSWERS", answers_2018, &
                  "If true, use the order of arithmetic and expressions that recover the "//&
                  "answers from the end of 2018.  Otherwise, use updated and more robust "//&
                  "forms of the same expressions.", default=default_2018_answers)
-    if (answers_2018) then
-      OBC%remap_answer_date = 20181231
-    else
-      OBC%remap_answer_date = 20190101
-    endif
+    ! Revise inconsistent default answer dates for remapping.
+    if (answers_2018 .and. (default_answer_date >= 20190101)) default_answer_date = 20181231
+    if (.not.answers_2018 .and. (default_answer_date < 20190101)) default_answer_date = 20190101
+    call get_param(param_file, mdl, "REMAPPING_ANSWER_DATE", OBC%remap_answer_date, &
+                 "The vintage of the expressions and order of arithmetic to use for remapping.  "//&
+                 "Values below 20190101 result in the use of older, less accurate expressions "//&
+                 "that were in use at the end of 2018.  Higher values result in the use of more "//&
+                 "robust and accurate forms of mathematically equivalent expressions.  "//&
+                 "If both REMAPPING_2018_ANSWERS and REMAPPING_ANSWER_DATE are specified, the "//&
+                 "latter takes precedence.", default=default_answer_date)
 
     allocate(OBC%remap_CS)
     call initialize_remapping(OBC%remap_CS, remappingScheme, boundary_extrapolation = .false., &

src/diagnostics/MOM_diagnostics.F90

@@ -1587,19 +1587,24 @@ subroutine MOM_diagnostics_init(MIS, ADp, CDp, Time, G, GV, US, param_file, diag
                  "starting point for iterations.", default=.true.)
   call get_param(param_file, mdl, "DEFAULT_ANSWER_DATE", default_answer_date, &
                  "This sets the default value for the various _ANSWER_DATE parameters.", &
-                 default=99991231, do_not_log=.true.)
+                 default=99991231)
   call get_param(param_file, mdl, "DEFAULT_2018_ANSWERS", default_2018_answers, &
                  "This sets the default value for the various _2018_ANSWERS parameters.", &
                  default=(default_answer_date<20190101))
   call get_param(param_file, mdl, "REMAPPING_2018_ANSWERS", remap_answers_2018, &
                  "If true, use the order of arithmetic and expressions that recover the "//&
                  "answers from the end of 2018.  Otherwise, use updated and more robust "//&
                  "forms of the same expressions.", default=default_2018_answers)
-  if (remap_answers_2018) then
-    remap_answer_date = 20181231
-  else
-    remap_answer_date = 20190101
-  endif
+  ! Revise inconsistent default answer dates for remapping.
+  if (remap_answers_2018 .and. (default_answer_date >= 20190101)) default_answer_date = 20181231
+  if (.not.remap_answers_2018 .and. (default_answer_date < 20190101)) default_answer_date = 20190101
+  call get_param(param_file, mdl, "REMAPPING_ANSWER_DATE", remap_answer_date, &
+                 "The vintage of the expressions and order of arithmetic to use for remapping.  "//&
+                 "Values below 20190101 result in the use of older, less accurate expressions "//&
+                 "that were in use at the end of 2018.  Higher values result in the use of more "//&
+                 "robust and accurate forms of mathematically equivalent expressions.  "//&
+                 "If both REMAPPING_2018_ANSWERS and REMAPPING_ANSWER_DATE are specified, the "//&
+                 "latter takes precedence.", default=default_answer_date)
 
   call get_param(param_file, mdl, "SPLIT", split, default=.true., do_not_log=.true.)
 

src/framework/MOM_diag_mediator.F90

@@ -3181,19 +3181,24 @@ subroutine diag_mediator_init(G, GV, US, nz, param_file, diag_cs, doc_file_dir)
                  default=1)
   call get_param(param_file, mdl, "DEFAULT_ANSWER_DATE", default_answer_date, &
                  "This sets the default value for the various _ANSWER_DATE parameters.", &
-                 default=99991231, do_not_log=.true.)
+                 default=99991231)
   call get_param(param_file, mdl, "DEFAULT_2018_ANSWERS", default_2018_answers, &
                  "This sets the default value for the various _2018_ANSWERS parameters.", &
                  default=(default_answer_date<20190101))
   call get_param(param_file, mdl, "REMAPPING_2018_ANSWERS", remap_answers_2018, &
                  "If true, use the order of arithmetic and expressions that recover the "//&
                  "answers from the end of 2018.  Otherwise, use updated and more robust "//&
                  "forms of the same expressions.", default=default_2018_answers)
-  if (remap_answers_2018) then
-    remap_answer_date = 20181231
-  else
-    remap_answer_date = 20190101
-  endif
+  ! Revise inconsistent default answer dates for remapping.
+  if (remap_answers_2018 .and. (default_answer_date >= 20190101)) default_answer_date = 20181231
+  if (.not.remap_answers_2018 .and. (default_answer_date < 20190101)) default_answer_date = 20190101
+  call get_param(param_file, mdl, "REMAPPING_ANSWER_DATE", remap_answer_date, &
+                 "The vintage of the expressions and order of arithmetic to use for remapping.  "//&
+                 "Values below 20190101 result in the use of older, less accurate expressions "//&
+                 "that were in use at the end of 2018.  Higher values result in the use of more "//&
+                 "robust and accurate forms of mathematically equivalent expressions.  "//&
+                 "If both REMAPPING_2018_ANSWERS and REMAPPING_ANSWER_DATE are specified, the "//&
+                 "latter takes precedence.", default=default_answer_date)
   call get_param(param_file, mdl, 'USE_GRID_SPACE_DIAGNOSTIC_AXES', diag_cs%grid_space_axes, &
                  'If true, use a grid index coordinate convention for diagnostic axes. ',&
                  default=.false.)

src/initialization/MOM_state_initialization.F90

@@ -1198,20 +1198,30 @@ subroutine trim_for_ice(PF, G, GV, US, ALE_CSp, tv, h, just_read)
   call get_param(PF, mdl, "TRIMMING_USES_REMAPPING", use_remapping, &
                  'When trimming the column, also remap T and S.', &
                  default=.false., do_not_log=just_read)
-  remap_answers_2018 = .true.
   if (use_remapping) then
     call get_param(PF, mdl, "DEFAULT_ANSWER_DATE", default_answer_date, &
                  "This sets the default value for the various _ANSWER_DATE parameters.", &
-                 default=99991231, do_not_log=.true.)
+                 default=99991231)
     call get_param(PF, mdl, "DEFAULT_2018_ANSWERS", default_2018_answers, &
                  "This sets the default value for the various _2018_ANSWERS parameters.", &
                  default=(default_answer_date<20190101))
     call get_param(PF, mdl, "REMAPPING_2018_ANSWERS", remap_answers_2018, &
                  "If true, use the order of arithmetic and expressions that recover the "//&
                  "answers from the end of 2018.  Otherwise, use updated and more robust "//&
                  "forms of the same expressions.", default=default_2018_answers)
+    ! Revise inconsistent default answer dates for remapping.
+    if (remap_answers_2018 .and. (default_answer_date >= 20190101)) default_answer_date = 20181231
+    if (.not.remap_answers_2018 .and. (default_answer_date < 20190101)) default_answer_date = 20190101
+    call get_param(PF, mdl, "REMAPPING_ANSWER_DATE", remap_answer_date, &
+                 "The vintage of the expressions and order of arithmetic to use for remapping.  "//&
+                 "Values below 20190101 result in the use of older, less accurate expressions "//&
+                 "that were in use at the end of 2018.  Higher values result in the use of more "//&
+                 "robust and accurate forms of mathematically equivalent expressions.  "//&
+                 "If both REMAPPING_2018_ANSWERS and REMAPPING_ANSWER_DATE are specified, the "//&
+                 "latter takes precedence.", default=default_answer_date)
+  else
+    remap_answer_date = 20181231
   endif
-  remap_answer_date = 20190101 ; if (remap_answers_2018) remap_answer_date = 20181231
 
   if (just_read) return ! All run-time parameters have been read, so return.
 
@@ -2475,6 +2485,7 @@ subroutine MOM_temp_salt_initialize_from_Z(h, tv, depth_tot, G, GV, US, PF, just
   logical :: remap_answers_2018   ! If true, use the order of arithmetic and expressions that
                                   ! recover the remapping answers from 2018.  If false, use more
                                   ! robust forms of the same remapping expressions.
+  integer :: default_remap_ans_date ! The default setting for remap_answer_date
   integer :: remap_answer_date    ! The vintage of the order of arithmetic and expressions to use
                                   ! for remapping.  Values below 20190101 recover the remapping
                                   ! answers from 2018, while higher values use more robust
@@ -2562,7 +2573,7 @@ subroutine MOM_temp_salt_initialize_from_Z(h, tv, depth_tot, G, GV, US, PF, just
                  default=.false., do_not_log=just_read)
   call get_param(PF, mdl, "DEFAULT_ANSWER_DATE", default_answer_date, &
                  "This sets the default value for the various _ANSWER_DATE parameters.", &
-                 default=99991231, do_not_log=.true.)
+                 default=99991231)
   call get_param(PF, mdl, "DEFAULT_2018_ANSWERS", default_2018_answers, &
                  "This sets the default value for the various _2018_ANSWERS parameters.", &
                  default=(default_answer_date<20190101))
@@ -2576,7 +2587,17 @@ subroutine MOM_temp_salt_initialize_from_Z(h, tv, depth_tot, G, GV, US, PF, just
                  "If true, use the order of arithmetic and expressions that recover the "//&
                  "answers from the end of 2018.  Otherwise, use updated and more robust "//&
                  "forms of the same expressions.", default=default_2018_answers)
-    remap_answer_date = 20190101 ; if (remap_answers_2018) remap_answer_date = 20181231
+    ! Revise inconsistent default answer dates for remapping.
+    default_remap_ans_date = default_answer_date
+    if (remap_answers_2018 .and. (default_remap_ans_date >= 20190101)) default_remap_ans_date = 20181231
+    if (.not.remap_answers_2018 .and. (default_remap_ans_date < 20190101)) default_remap_ans_date = 20190101
+    call get_param(PF, mdl, "REMAPPING_ANSWER_DATE", remap_answer_date, &
+                 "The vintage of the expressions and order of arithmetic to use for remapping.  "//&
+                 "Values below 20190101 result in the use of older, less accurate expressions "//&
+                 "that were in use at the end of 2018.  Higher values result in the use of more "//&
+                 "robust and accurate forms of mathematically equivalent expressions.  "//&
+                 "If both REMAPPING_2018_ANSWERS and REMAPPING_ANSWER_DATE are specified, the "//&
+                 "latter takes precedence.", default=default_remap_ans_date)
   endif
   call get_param(PF, mdl, "HOR_REGRID_2018_ANSWERS", hor_regrid_answers_2018, &
                  "If true, use the order of arithmetic for horizonal regridding that recovers "//&

src/initialization/MOM_tracer_initialization_from_Z.F90

@@ -83,6 +83,7 @@ subroutine MOM_initialize_tracer_from_Z(h, tr, G, GV, US, PF, src_file, src_var_
   logical :: remap_answers_2018   ! If true, use the order of arithmetic and expressions that
                                   ! recover the remapping answers from 2018.  If false, use more
                                   ! robust forms of the same remapping expressions.
+  integer :: default_remap_ans_date ! The default setting for remap_answer_date
   integer :: remap_answer_date    ! The vintage of the order of arithmetic and expressions to use
                                   ! for remapping.  Values below 20190101 recover the remapping
                                   ! answers from 2018, while higher values use more robust
@@ -115,7 +116,7 @@ subroutine MOM_initialize_tracer_from_Z(h, tr, G, GV, US, PF, src_file, src_var_
                  default="PLM")
   call get_param(PF, mdl, "DEFAULT_ANSWER_DATE", default_answer_date, &
                  "This sets the default value for the various _ANSWER_DATE parameters.", &
-                 default=99991231, do_not_log=.true.)
+                 default=99991231)
   call get_param(PF, mdl, "DEFAULT_2018_ANSWERS", default_2018_answers, &
                  "This sets the default value for the various _2018_ANSWERS parameters.", &
                  default=(default_answer_date<20190101))
@@ -124,11 +125,17 @@ subroutine MOM_initialize_tracer_from_Z(h, tr, G, GV, US, PF, src_file, src_var_
                  "If true, use the order of arithmetic and expressions that recover the "//&
                  "answers from the end of 2018.  Otherwise, use updated and more robust "//&
                  "forms of the same expressions.", default=default_2018_answers)
-   if (remap_answers_2018) then
-      remap_answer_date = 20181231
-    else
-      remap_answer_date = 20190101
-    endif
+    ! Revise inconsistent default answer dates for remapping.
+    default_remap_ans_date = default_answer_date
+    if (remap_answers_2018 .and. (default_remap_ans_date >= 20190101)) default_remap_ans_date = 20181231
+    if (.not.remap_answers_2018 .and. (default_remap_ans_date < 20190101)) default_remap_ans_date = 20190101
+    call get_param(PF, mdl, "REMAPPING_ANSWER_DATE", remap_answer_date, &
+                 "The vintage of the expressions and order of arithmetic to use for remapping.  "//&
+                 "Values below 20190101 result in the use of older, less accurate expressions "//&
+                 "that were in use at the end of 2018.  Higher values result in the use of more "//&
+                 "robust and accurate forms of mathematically equivalent expressions.  "//&
+                 "If both REMAPPING_2018_ANSWERS and REMAPPING_ANSWER_DATE are specified, the "//&
+                 "latter takes precedence.", default=default_remap_ans_date)
   endif
   call get_param(PF, mdl, "HOR_REGRID_2018_ANSWERS", hor_regrid_answers_2018, &
                  "If true, use the order of arithmetic for horizonal regridding that recovers "//&