IAU for MOM6 cycling runs

[Dooruk]

Some changes required to have IAU for the ocean model. This is a more stable and easier way of introducing increments to the ocean state rather than updating restart files.

Updated background_error parameters to conform with the 0.25 degrees setup.

IAU requires a file called MOM_oda_incupd in the experiment directory which is augmented with the MOM_input if IAU switch is turned on. Contents of the file is below. Increment is distributed equally throughout ODA_INCUPD_NHOURS. For now it does not have U,V increments due to some changes required within SOCA and static bump files would need to be updated to consider U,V fields.

! === module MOM_oda_incupd ===
ODA_INCUPD = True   ! [Boolean] default = False
                             ! If true, oda incremental updates will be applied
                             ! everywhere in the domain.
ODA_INCUPD_FILE = "mom6_increment.nc"   ! The name of the file with the T,S,h increments.

ODA_TEMPINC_VAR = "Temp"        ! default = "ptemp_inc"
                                ! The name of the potential temperature inc. variable in
				      	   ! ODA_INCUPD_FILE.
ODA_SALTINC_VAR = "Salt"        ! default = "sal_inc"
                                ! The name of the salinity inc. variable in
                                ! ODA_INCUPD_FILE.
ODA_THK_VAR = "h"               ! default = "h"
                                ! The name of the int. depth inc. variable in
                                ! ODA_INCUPD_FILE.
ODA_INCUPD_UV = false            !
ODA_UINC_VAR = "u"              ! default = "u_inc"
                                ! The name of the zonal vel. inc. variable in
                                ! ODA_INCUPD_UV_FILE.
ODA_VINC_VAR = "v"              ! default = "v_inc"
                                ! The name of the meridional vel. inc. variable in
                                ! ODA_INCUPD_UV_FILE.
ODA_INCUPD_NHOURS = 3.0            ! default=3.0

[danholdaway]

Thanks for adding the ocean IAU, great to have this. Two minor changes but otherwise LGTM

[Dooruk]

All should be good now.

Eventually, this will require some static Swell / JEDI files to be updated, but now that CICE6 updates are on the way (as well as GEOS version change) we can just merge these changes and we can update static files all together. Default for IAU is off so things should run.