How to generate restarts for MOM6 coupled model ?

1 Atmosphere and Sea Ice Restart

Identify atmosphere and sea ice restarts, for e.g., /nfs3m/archive/sfa_cache04/users/g06/ehackert/GEOS5.0/eh025/restarts/Y2021/restarts.e20210630_00z.tar

If the file is archived, demigrate it:

dmget <path_to_file>/restarts.e20210630_00z.tar &

Once it is available, do following:

1. untar it.
2. Strip prefix

rename eh025. '' eh025.*

and suffix in names of restart files:

rename .e20210630_00z.Icarus-3_3_p2.a180x1080_o1440x1080.newtile_CF0180x6C_DE0360xPE0180.nc4 '' *.e20210630_00z.Icarus-3_3_p2.a180x1080_o1440x1080.newtile_CF0180x6C_DE0360xPE0180.nc4

2 cap_restart

Create a cap_restart that records the date of the restarts in the format (in one line):

yyyymmdd hhmmss

3 Run the Remap Script

Run GEOSgcm/install/bin/remap_restarts.py from your build, or use following sample template.

#
# This template file can be filled with questionary or manually
#
#

input:
  air:
    drymass: 1
    hydrostatic: 0
  shared:
    MERRA-2: false
    agrid: C180
    bcs_dir: /discover/nobackup/projects/gmao/ssd/aogcm/atmosphere_bcs/Icarus/MOM5//CF0180x6C_TM1440xTM1080/
    expid: ''
    ogrid: 1440X1080
    rst_dir: /discover/nobackup/sakella/restarts/restarts_S2S_19Nov2022/
    yyyymmddhh: '2021063021'
  surface:
    zoom: '2'
    wemin: '26'
    # it supports three models: catch, catchcnclm40, catchcnclm45
    catch_model: catch
    # if catch_tilefile is null, it searches bcs_dir
    catch_tilefile:
output:
  shared:
    agrid: C180
    bcs_dir: /discover/nobackup/projects/gmao/ssd/aogcm/atmosphere_bcs/Icarus-NLv3/MOM6//CF0180x6C_TM1440xTM1080_newtopo/
    expid: test1
    ogrid: 1440X1080
    out_dir: /discover/nobackup/sakella/restarts/restarts_S2S_19Nov2022/output/
  air:
    # remap upper air or not
    remap: true
    nlevel: '72'
  surface:
    split_saltwater: true
    surflay: 50.0
    wemin: '13'
    # remap lake, saltwater, landicet
    remap_water: true
    # remap catch(cn)
    remap_catch: true
    # if catch_tilefile is null, it searches bcs_dir
    catch_tilefile:
  analysis:
    bkg: false
    aqua: true
    lcv: true

slurm:
  account: g0613
  qos: debug
  constraint: sky

Be sure to:

• Set modules: source .../GEOSgcm/@env/g5_modules
• Use the ⬆️ template as .../GEOSgcm/install/bin/remap_restarts.py -c remap_params.yaml

4 Copy the Restart Files in the Experiment Directory

Once all (atmosphere and sea ice) restarts have been generated, copy them to the experiment location and run. If MOM6 ocean is starting from climatology, use this. Otherwise provide restarts and again, follow instructions provided here to properly configure.