+*Update parameter defaults for 2024 and 2025, including EQN_OF_STATE

.testing/tc0/MOM_input

@@ -235,7 +235,7 @@ DIAG_AS_CHKSUM = True
 DEBUG = True
 GRID_ROTATION_ANGLE_BUGS = True !   [Boolean] default = True
 USE_GM_WORK_BUG = True          !   [Boolean] default = True
-FIX_UNSPLIT_DT_VISC_BUG = False !   [Boolean] default = False
 USE_LAND_MASK_FOR_HVISC = False !   [Boolean] default = False
 GUST_CONST = 0.02               !   [Pa] default = 0.02
 FIX_USTAR_GUSTLESS_BUG = False  !   [Boolean] default = False
+

.testing/tc1.a/MOM_tc_variant

@@ -1,2 +1,2 @@
 #override SPLIT=False
-#override FIX_UNSPLIT_DT_VISC_BUG = False !   [Boolean] default = False
+#override UNSPLIT_DT_VISC_BUG = True      !   [Boolean] default = False

.testing/tc1.b/MOM_tc_variant

@@ -1,3 +1,3 @@
 #override SPLIT=False
 #override USE_RK2=True
-#override FIX_UNSPLIT_DT_VISC_BUG = False !   [Boolean] default = False
+#override UNSPLIT_DT_VISC_BUG = True      !   [Boolean] default = False

.testing/tc1/MOM_input

@@ -595,3 +595,17 @@ BULKML_CONV_MOMENTUM_BUG = True !   [Boolean] default = True
 PEN_SW_ABSORB_MINTHICK = 0.001  !   [m] default = 0.001
 GUST_CONST = 0.02               !   [Pa] default = 0.02
 FIX_USTAR_GUSTLESS_BUG = False  !   [Boolean] default = False
+
+
+! Explicitly use the defaults from late 2024
+EQN_OF_STATE = "WRIGHT"     ! default = "WRIGHT_FULL"
+HOR_DIFF_ANSWER_DATE = 20240101
+HOR_DIFF_LIMIT_BUG = True
+
+! Explicitly use the defaults from early 2025
+VISC_REM_BUG = True
+DRAG_DIFFUSIVITY_ANSWER_DATE = 20250101
+FRICTWORK_BUG = True
+HOR_DIFF_ANSWER_DATE = 20240101
+HOR_DIFF_LIMIT_BUG = True
+MASS_WEIGHT_IN_PRESSURE_GRADIENT_TOP = False

.testing/tc2/MOM_input

@@ -627,3 +627,16 @@ USE_MLD_ITERATION = False       !   [Boolean] default = False
 PEN_SW_ABSORB_MINTHICK = 0.001  !   [m] default = 0.001
 GUST_CONST = 0.02               !   [Pa] default = 0.02
 FIX_USTAR_GUSTLESS_BUG = False  !   [Boolean] default = False
+
+! Explicitly use the defaults from late 2024
+EQN_OF_STATE = "WRIGHT"     ! default = "WRIGHT_FULL"
+TIDES_ANSWER_DATE = 20230630
+NDIFF_ANSWER_DATE = 20240101
+BACKSCATTER_UNDERBOUND = True
+
+! Explicitly use the defaults from early 2025
+VISC_REM_BUG = True
+DRAG_DIFFUSIVITY_ANSWER_DATE = 20250101
+FRICTWORK_BUG = True
+NDIFF_ANSWER_DATE = 20240101
+MASS_WEIGHT_IN_PRESSURE_GRADIENT_TOP = False

.testing/tc3/MOM_input

@@ -480,3 +480,8 @@ KAPPA_SHEAR_ITER_BUG = True     !   [Boolean] default = True
 KAPPA_SHEAR_ALL_LAYER_TKE_BUG = True !   [Boolean] default = True
 GUST_CONST = 0.02               !   [Pa] default = 0.02
 FIX_USTAR_GUSTLESS_BUG = False  !   [Boolean] default = False
+
+! Explicitly use the defaults from early 2025
+VISC_REM_BUG = True
+DRAG_DIFFUSIVITY_ANSWER_DATE = 20250101
+FRICTWORK_BUG = True

.testing/tc4/MOM_input

@@ -411,9 +411,12 @@ DEBUG = True
 
 INTERPOLATE_RES_FN = True       !   [Boolean] default = True
 GILL_EQUATORIAL_LD = False      !   [Boolean] default = False
-FIX_UNSPLIT_DT_VISC_BUG = False !   [Boolean] default = False
 USE_LAND_MASK_FOR_HVISC = False !   [Boolean] default = False
 KAPPA_SHEAR_ITER_BUG = True     !   [Boolean] default = True
 KAPPA_SHEAR_ALL_LAYER_TKE_BUG = True !   [Boolean] default = True
 USE_MLD_ITERATION = False       !   [Boolean] default = False
 
+! Explicitly use the defaults from early 2025
+VISC_REM_BUG = True
+FRICTWORK_BUG = True
+MASS_WEIGHT_IN_PRESSURE_GRADIENT_TOP = False

config_src/external/GFDL_ocean_BGC/MOM_generic_tracer.F90

@@ -16,7 +16,7 @@ module MOM_generic_tracer
 ! ### These imports should not reach into FMS directly ###
 
 use MOM_ALE_sponge, only : ALE_sponge_CS
-use MOM_coms, only : EFP_type
+use MOM_coms, only : EFP_type, real_to_EFP
 use MOM_diag_mediator, only : diag_ctrl
 use MOM_error_handler, only : MOM_error, FATAL
 use MOM_file_parser, only : param_file_type
@@ -195,8 +195,14 @@ function MOM_generic_tracer_stock(h, stocks, G, GV, CS, names, units, stock_inde
   integer                                           :: MOM_generic_tracer_stock !< Return value, the
                                                                    !! number of stocks calculated here.
 
+  integer :: m
   MOM_generic_tracer_stock = 0
 
+  ! These should never be used, but they are set to avoid compile-time warnings
+  do m=1,size(names) ; names(m) = "" ; enddo
+  do m=1,size(units) ; units(m) = "" ; enddo
+  do m=1,size(stocks) ; stocks(m) = real_to_EFP(0.0) ; enddo
+
 end function MOM_generic_tracer_stock
 
 !> This subroutine finds the global min and max of either of all available
@@ -227,8 +233,24 @@ function MOM_generic_tracer_min_max(ind_start, got_minmax, gmin, gmax, G, CS, na
   integer                                       :: MOM_generic_tracer_min_max !< Return value, the
                                                           !! number of tracers done here.
 
+  integer :: m
+
   MOM_generic_tracer_min_max = 0
 
+  ! These should never be used, but they are set to avoid compile-time warnings.  Note that the minimum values
+  ! are delibarately set to be larger than the maximum values.
+  got_minmax(:) = .false.
+  gmax(:) = -huge(gmax)
+  gmin(:) = huge(gmin)
+  do m=1,size(names) ; names(m) = "" ; enddo
+  do m=1,size(units) ; units(m) = "" ; enddo
+  if (present(xgmin)) xgmin(:) = 0.0
+  if (present(ygmin)) ygmin(:) = 0.0
+  if (present(zgmin)) zgmin(:) = 0.0
+  if (present(xgmax)) xgmax(:) = 0.0
+  if (present(ygmax)) ygmax(:) = 0.0
+  if (present(zgmax)) zgmax(:) = 0.0
+
 end function MOM_generic_tracer_min_max
 
 !> This subroutine calculates the surface state and sets coupler values for
@@ -271,6 +293,8 @@ subroutine MOM_generic_tracer_get(name,member,array, CS)
                                                   ! arbitrary units [A]
   character(len=128), parameter :: sub_name = 'MOM_generic_tracer_get'
 
+  array(:,:,:) = huge(array)
+
 end subroutine MOM_generic_tracer_get
 
 !> This subroutine deallocates the memory owned by this module.

src/ALE/MOM_regridding.F90

@@ -313,7 +313,7 @@ subroutine initialize_regridding(CS, GV, US, max_depth, param_file, mdl, coord_m
                  "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.", &
-                 default=20181231, do_not_log=.not.GV%Boussinesq) ! ### change to default=default_answer_date)
+                 default=default_answer_date, do_not_log=.not.GV%Boussinesq)
     if (.not.GV%Boussinesq) regrid_answer_date = max(regrid_answer_date, 20230701)
     call set_regrid_params(CS, regrid_answer_date=regrid_answer_date)
   endif

src/core/MOM.F90

@@ -314,8 +314,6 @@ module MOM
   logical :: useMEKE                 !< If true, call the MEKE parameterization.
   logical :: use_stochastic_EOS      !< If true, use the stochastic EOS parameterizations.
   logical :: useWaves                !< If true, update Stokes drift
-  logical :: use_diabatic_time_bug   !< If true, uses the wrong calendar time for diabatic processes,
-                                     !! as was done in MOM6 versions prior to February 2018.
   real :: dtbt_reset_period          !< The time interval between dynamic recalculation of the
                                      !! barotropic time step [T ~> s]. If this is negative dtbt is never
                                      !! calculated, and if it is 0, dtbt is calculated every step.
@@ -840,15 +838,9 @@ subroutine step_MOM(forces_in, fluxes_in, sfc_state, Time_start, time_int_in, CS
 
   rel_time = 0.0
   do n=1,n_max
-    if (CS%use_diabatic_time_bug) then
-      ! This wrong form of update was used until Feb 2018, recovered with CS%use_diabatic_time_bug=T.
-      CS%Time = Time_start + real_to_time(US%T_to_s*int(floor(rel_time+0.5*dt+0.5)))
-      rel_time = rel_time + dt
-    else
-      rel_time = rel_time + dt ! The relative time at the end of the step.
-      ! Set the universally visible time to the middle of the time step.
-      CS%Time = Time_start + real_to_time(US%T_to_s*(rel_time - 0.5*dt))
-    endif
+    rel_time = rel_time + dt ! The relative time at the end of the step.
+    ! Set the universally visible time to the middle of the time step.
+    CS%Time = Time_start + real_to_time(US%T_to_s*(rel_time - 0.5*dt))
     ! Set the local time to the end of the time step.
     Time_local = Time_start + real_to_time(US%T_to_s*rel_time)
 
@@ -878,16 +870,12 @@ subroutine step_MOM(forces_in, fluxes_in, sfc_state, Time_start, time_int_in, CS
       endif
 
       end_time_thermo = Time_local
-      if (dtdia > dt .and. .not. CS%use_diabatic_time_bug) then
+      if (dtdia > dt) then
         ! If necessary, temporarily reset CS%Time to the center of the period covered
         ! by the call to step_MOM_thermo, noting that they begin at the same time.
-        ! This step was missing prior to Feb 2018, and is skipped with CS%use_diabatic_time_bug=T.
         CS%Time = CS%Time + real_to_time(0.5*US%T_to_s*(dtdia-dt))
-      endif
-      if (dtdia > dt .or. CS%use_diabatic_time_bug) then
         ! The end-time of the diagnostic interval needs to be set ahead if there
         ! are multiple dynamic time steps worth of thermodynamics applied here.
-        ! This line was not conditional prior to Feb 2018, recovered with CS%use_diabatic_time_bug=T.
         end_time_thermo = Time_local + real_to_time(US%T_to_s*(dtdia-dt))
       endif
 
@@ -903,8 +891,7 @@ subroutine step_MOM(forces_in, fluxes_in, sfc_state, Time_start, time_int_in, CS
       CS%t_dyn_rel_thermo = -dtdia
       if (showCallTree) call callTree_waypoint("finished diabatic_first (step_MOM)")
 
-      if (dtdia > dt .and. .not. CS%use_diabatic_time_bug) & ! Reset CS%Time to its previous value.
-        ! This step was missing prior to Feb 2018, recovered with CS%use_diabatic_time_bug=T.
+      if (dtdia > dt) & ! Reset CS%Time to its previous value.
         CS%Time = Time_start + real_to_time(US%T_to_s*(rel_time - 0.5*dt))
     endif ! end of block "(CS%diabatic_first .and. (CS%t_dyn_rel_adv==0.0))"
 
@@ -1004,8 +991,7 @@ subroutine step_MOM(forces_in, fluxes_in, sfc_state, Time_start, time_int_in, CS
 
       ! If necessary, temporarily reset CS%Time to the center of the period covered
       ! by the call to step_MOM_thermo, noting that they end at the same time.
-      ! This step was missing prior to Feb 2018, and is skipped with CS%use_diabatic_time_bug=T.
-      if (dtdia > dt .and. .not. CS%use_diabatic_time_bug) &
+      if (dtdia > dt) &
         CS%Time = CS%Time - real_to_time(0.5*US%T_to_s*(dtdia-dt))
 
       ! Apply diabatic forcing, do mixing, and regrid.
@@ -1024,8 +1010,7 @@ subroutine step_MOM(forces_in, fluxes_in, sfc_state, Time_start, time_int_in, CS
       endif
 
       ! Reset CS%Time to its previous value.
-      ! This step was missing prior to Feb 2018, and is skipped with CS%use_diabatic_time_bug=T.
-      if (dtdia > dt .and. .not. CS%use_diabatic_time_bug) &
+      if (dtdia > dt) &
         CS%Time = Time_start + real_to_time(US%T_to_s*(rel_time - 0.5*dt))
     endif
 
@@ -2733,11 +2718,6 @@ subroutine initialize_MOM(Time, Time_init, param_file, dirs, CS, &
                default=default_answer_date, do_not_log=non_Bous)
   if (non_Bous) CS%answer_date = 99991231
 
-  call get_param(param_file, "MOM", "USE_DIABATIC_TIME_BUG", CS%use_diabatic_time_bug, &
-                 "If true, uses the wrong calendar time for diabatic processes, as was "//&
-                 "done in MOM6 versions prior to February 2018. This is not recommended.", &
-                 default=.false.)
-
   call get_param(param_file, "MOM", "SAVE_INITIAL_CONDS", save_IC, &
                  "If true, write the initial conditions to a file given "//&
                  "by IC_OUTPUT_FILE.", default=.false.)

src/core/MOM_PressureForce_FV.F90

@@ -2076,16 +2076,19 @@ subroutine PressureForce_FV_init(Time, G, GV, US, param_file, diag, CS, ADp, SAL
                  default=enable_bugs)
   call get_param(param_file, mdl, "TIDES", CS%tides, &
                  "If true, apply tidal momentum forcing.", default=.false.)
-  call get_param(param_file, '', "DEFAULT_ANSWER_DATE", default_answer_date, default=99991231)
-  if (CS%tides) &
+  if (CS%tides) then
+    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)
     call get_param(param_file, mdl, "TIDES_ANSWER_DATE", CS%tides_answer_date, "The vintage of "//&
                   "self-attraction and loading (SAL) and tidal forcing calculations.  Setting "//&
                   "dates before 20230701 recovers old answers (Boussinesq and non-Boussinesq "//&
                   "modes) when SAL is part of the tidal forcing calculation.  The answer "//&
                   "difference is only at bit level and due to a reordered summation.  Setting "//&
                   "dates before 20250201 recovers answers (Boussinesq mode) that interface "//&
                   "heights are modified before pressure force integrals are calculated.", &
-                  default=20230630, do_not_log=(.not.CS%tides))
+                  default=default_answer_date, do_not_log=(.not.CS%tides))
+  endif
   call get_param(param_file, mdl, "CALCULATE_SAL", CS%calculate_SAL, &
                  "If true, calculate self-attraction and loading.", default=CS%tides)
   if (CS%calculate_SAL) &
@@ -2128,7 +2131,7 @@ subroutine PressureForce_FV_init(Time, G, GV, US, param_file, diag, CS, ADp, SAL
                  "If true and MASS_WEIGHT_IN_PRESSURE_GRADIENT is true, use mass weighting when "//&
                  "interpolating T/S for integrals near the top of the water column in FV "//&
                  "pressure gradient calculations. ", &
-                 default=.false.) !### Change Default to MASS_WEIGHT_IN_PRESSURE_GRADIENT?
+                 default=useMassWghtInterp)
   call get_param(param_file, mdl, "MASS_WEIGHT_IN_PGF_NONBOUS_BUG", MassWghtInterp_NonBous_bug, &
                  "If true, use a masking bug in non-Boussinesq calculations with mass weighting "//&
                  "when interpolating T/S for integrals near the bathymetry in FV pressure "//&

src/core/MOM_barotropic.F90

@@ -5526,7 +5526,7 @@ subroutine barotropic_init(u, v, h, Time, G, GV, US, param_file, diag, CS, &
 
   call get_param(param_file, mdl, "ENABLE_BUGS_BY_DEFAULT", enable_bugs, &
                  default=.true., do_not_log=.true.)  ! This is logged from MOM.F90.
-  call get_param(param_file, mdl, "VISC_REM_BUG", visc_rem_bug, default=enable_bugs, do_not_log=.true.)
+  call get_param(param_file, mdl, "VISC_REM_BUG", visc_rem_bug, default=.false., do_not_log=.true.)
   call get_param(param_file, mdl, "VISC_REM_BT_WEIGHT_BUG", CS%wt_uv_bug, &
                  "If true, recover a bug in barotropic solver that uses an unnormalized weight "//&
                  "function for vertical averages of baroclinic velocity and forcing. Default "//&

src/core/MOM_dynamics_split_RK2.F90

@@ -1488,7 +1488,7 @@ subroutine initialize_dyn_split_RK2(u, v, h, tv, uh, vh, eta, Time, G, GV, US, p
                  "If true, visc_rem_[uv] in split mode is incorrectly calculated or accounted "//&
                  "for in two places. This parameter controls the defaults of two individual "//&
                  "flags, VISC_REM_TIMESTEP_BUG in MOM_dynamics_split_RK2(b) and "//&
-                 "VISC_REM_BT_WEIGHT_BUG in MOM_barotropic.", default=enable_bugs)
+                 "VISC_REM_BT_WEIGHT_BUG in MOM_barotropic.", default=.false.)
   call get_param(param_file, mdl, "VISC_REM_TIMESTEP_BUG", CS%visc_rem_dt_bug, &
                  "If true, recover a bug that uses dt_pred rather than dt in "//&
                  "vertvisc_remnant() at the end of predictor stage for the following "//&

src/core/MOM_dynamics_split_RK2b.F90

@@ -1374,7 +1374,7 @@ subroutine initialize_dyn_split_RK2b(u, v, h, tv, uh, vh, eta, Time, G, GV, US,
                  "If true, visc_rem_[uv] in split mode is incorrectly calculated or accounted "//&
                  "for in two places. This parameter controls the defaults of two individual "//&
                  "flags, VISC_REM_TIMESTEP_BUG in MOM_dynamics_split_RK2(b) and "//&
-                 "VISC_REM_BT_WEIGHT_BUG in MOM_barotropic.", default=enable_bugs)
+                 "VISC_REM_BT_WEIGHT_BUG in MOM_barotropic.", default=.false.)
   call get_param(param_file, mdl, "VISC_REM_TIMESTEP_BUG", CS%visc_rem_dt_bug, &
                  "If true, recover a bug that uses dt_pred rather than dt in "//&
                  "vertvisc_remnant() at the end of predictor stage for the following "//&

src/core/MOM_dynamics_unsplit.F90

@@ -634,9 +634,6 @@ subroutine initialize_dyn_unsplit(u, v, h, tv, Time, G, GV, US, param_file, diag
   character(len=48) :: flux_units
   ! This include declares and sets the variable "version".
 # include "version_variable.h"
-  logical :: use_correct_dt_visc
-  logical :: test_value  ! This is used to determine whether a logical parameter is being set explicitly.
-  logical :: explicit_bug, explicit_fix ! These indicate which parameters are set explicitly.
   integer :: isd, ied, jsd, jed, nz, IsdB, IedB, JsdB, JedB
   isd = G%isd ; ied = G%ied ; jsd = G%jsd ; jed = G%jed ; nz = GV%ke
   IsdB = G%IsdB ; IedB = G%IedB ; JsdB = G%JsdB ; JedB = G%JedB
@@ -655,33 +652,6 @@ subroutine initialize_dyn_unsplit(u, v, h, tv, Time, G, GV, US, param_file, diag
   call log_version(param_file, mdl, version, "")
 
   call get_param(param_file, mdl, "UNSPLIT_DT_VISC_BUG", CS%dt_visc_bug, &
-                 "If false, use the correct timestep in the viscous terms applied in the first "//&
-                 "predictor step with the unsplit time stepping scheme, and in the calculation "//&
-                 "of the turbulent mixed layer properties for viscosity with unsplit or "//&
-                 "unsplit_RK2.  If true, an older incorrect value is used.", &
-                 default=.false., do_not_log=.true.)
-  ! This is used to test whether UNSPLIT_DT_VISC_BUG is being actively set.
-  call get_param(param_file, mdl, "UNSPLIT_DT_VISC_BUG", test_value, default=.true., do_not_log=.true.)
-  explicit_bug = CS%dt_visc_bug .eqv. test_value
-  call get_param(param_file, mdl, "FIX_UNSPLIT_DT_VISC_BUG", use_correct_dt_visc, &
-                 "If true, use the correct timestep in the viscous terms applied in the first "//&
-                 "predictor step with the unsplit time stepping scheme, and in the calculation "//&
-                 "of the turbulent mixed layer properties for viscosity with unsplit or "//&
-                 "unsplit_RK2.", default=.true., do_not_log=.true.)
-  call get_param(param_file, mdl, "FIX_UNSPLIT_DT_VISC_BUG", test_value, default=.false., do_not_log=.true.)
-  explicit_fix = use_correct_dt_visc .eqv. test_value
-
-  if (explicit_bug .and. explicit_fix .and. (use_correct_dt_visc .eqv. CS%dt_visc_bug)) then
-    ! UNSPLIT_DT_VISC_BUG is being explicitly set, and should not be changed.
-    call MOM_error(FATAL, "UNSPLIT_DT_VISC_BUG and FIX_UNSPLIT_DT_VISC_BUG are both being set "//&
-                   "with inconsistent values.  FIX_UNSPLIT_DT_VISC_BUG is an obsolete "//&
-                   "parameter and should be removed.")
-  elseif (explicit_fix) then
-    call MOM_error(WARNING, "FIX_UNSPLIT_DT_VISC_BUG is an obsolete parameter.  "//&
-                   "Use UNSPLIT_DT_VISC_BUG instead (noting that it has the opposite sense).")
-    CS%dt_visc_bug = .not.use_correct_dt_visc
-  endif
-  call log_param(param_file, mdl, "UNSPLIT_DT_VISC_BUG", CS%dt_visc_bug, &
                  "If false, use the correct timestep in the viscous terms applied in the first "//&
                  "predictor step with the unsplit time stepping scheme, and in the calculation "//&
                  "of the turbulent mixed layer properties for viscosity with unsplit or "//&