1deg_jra55do_ryf: Address MOM warnings

[micaeljtoliveira]

MOM throws a few warnings (see bellow) when running this configuration. We should check and eventually fix these warnings.

WARNING from PE     0: MEKE_init: Initializing MEKE with a local equilibrium balance.


WARNING from PE     0: KVML is a deprecated parameter. Use KV_ML_INVZ2 instead.


WARNING from PE     0: bkgnd_mixing_init: a nonzero constant background diffusivity (KD) is specified along with HORIZ_VARYING_BACKGROUND


WARNING from PE     0: set_diffusivity_init: SIMPLE_TKE_TO_KD can not be used reliably with USE_REGRIDDING.


WARNING from PE     0: Unused line in MOM_input : CFC_BC_FILE = cfc_atm_20230310.nc


WARNING from PE     0: Unused line in MOM_input : INT_TIDE_DECAY_SCALE = 300.3003003003003

[minghangli-uni]

1. WARNING from PE 0: MEKE_init: Initializing MEKE with a local equilibrium balance.

This warning comes from the beginning of a run. It will disappear after a restart. Or initialise MEKE to 0 with the parameter coldStart. One can refer to MOM6/src/parameterizations/lateral/MOM_MEKE.F90

1426   ! Detect whether this instance of MEKE_init() is at the beginning of a run
1427   ! or after a restart. If at the beginning, we will initialize MEKE to a local
1428   ! equilibrium.
1429   CS%initialize = .not.query_initialized(MEKE%MEKE, "MEKE", restart_CS)
1430   if (coldStart) CS%initialize = .false.
1431   if (CS%initialize) call MOM_error(WARNING, &
1432                        "MEKE_init: Initializing MEKE with a local equilibrium balance.")

2. WARNING from PE 0: KVML is a deprecated parameter. Use KV_ML_INVZ2 instead.

In the current configuration 1deg, KVML and KV_ML_INVZ2 are the same parameter and are discouraged in MOM6. I would say leaving the warning there? Please correct me if I am wrong. The relevant snippet can be found in MOM6/src/parameterizations/vertical/MOM_vert_friction.F90

1921   CS%Kvml_invZ2 = 0.0
1922   if (GV%nkml < 1) then
1923     call get_param(param_file, mdl, "KV_ML_INVZ2", CS%Kvml_invZ2, &
1924                  "An extra kinematic viscosity in a mixed layer of thickness HMIX_FIXED, "//&
1925                  "with the actual viscosity scaling as 1/(z*HMIX_FIXED)^2, where z is the "//&
1926                  "distance from the surface, to allow for finite wind stresses to be "//&
1927                  "transmitted through infinitesimally thin surface layers.  This is an "//&
1928                  "older option for numerical convenience without a strong physical basis, "//&
1929                  "and its use is now discouraged.", &
1930                  units="m2 s-1", default=-1.0, scale=US%m2_s_to_Z2_T, do_not_log=.true.)
1931     if (CS%Kvml_invZ2 < 0.0) then
1932       call get_param(param_file, mdl, "KVML", CS%Kvml_invZ2, &
1933                  "The scale for an extra kinematic viscosity in the mixed layer", &
1934                  units="m2 s-1", default=0.0, scale=US%m2_s_to_Z2_T, do_not_log=.true.)
1935       if (CS%Kvml_invZ2 >= 0.0) &
1936         call MOM_error(WARNING, "KVML is a deprecated parameter. Use KV_ML_INVZ2 instead.")
1937     endif
1938     if (CS%Kvml_invZ2 < 0.0) CS%Kvml_invZ2 = 0.0
1939     call log_param(param_file, mdl, "KV_ML_INVZ2", US%Z2_T_to_m2_s*CS%Kvml_invZ2, &
1940                  "An extra kinematic viscosity in a mixed layer of thickness HMIX_FIXED, "//&
1941                  "with the actual viscosity scaling as 1/(z*HMIX_FIXED)^2, where z is the "//&
1942                  "distance from the surface, to allow for finite wind stresses to be "//&
1943                  "transmitted through infinitesimally thin surface layers.  This is an "//&
1944                  "older option for numerical convenience without a strong physical basis, "//&
1945                  "and its use is now discouraged.", &
1946                  units="m2 s-1", default=0.0)
1947   endif

[aekiss]

I think the MEKE warning can be ignored - equilibrium seems a sensible way to start a new run.
Note that today's meeting decided that for now we should leave MKE as-is or turn it off, but test it later https://forum.access-hive.org.au/t/namelist-configuration-discussion-meeting/1917/9

[access-hive-bot]

This issue has been mentioned on ACCESS Hive Community Forum. There might be relevant details there:

https://forum.access-hive.org.au/t/namelist-configuration-discussion-meeting/1917/9

[aekiss]

I don't understand why there's a KVML warning - KVML and KV_ML_INVZ2 are missing in MOM_input in 1deg_jra55do_ryf and KV_ML_INVZ2 is zero by default.