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How to run ACCESS-OM3 ice shelf configurations

Please see https://github.com/claireyung/mom6-panAn-iceshelf-tools/wiki for notes

Also refer to previous notes on the ACCESS-rOM3 panantarctic with no ice shelves here: https://github.com/claireyung/access-om3-configs/blob/8km_jra_ryf_obc2-sapphirerapid-Charrassin-newparams-rerun-Wright-spinup-accessom2IC-yr9/panantarctic_instructions.md

Important: requires small timestep at the start, may need more walltime, but with default number of cores should fit within normalsr 10 hr limit

Also important: Code changes are required, see https://github.com/ACCESS-NRI/MOM6/issues/29 and branch https://github.com/ACCESS-NRI/MOM6/tree/ice-shelf-dev

Also important: If changing files, think carefully about masks and coverage. See Claire's notes/contact her if you have questions. Otherwise you might allow the ocean to talk to the atmos in the ice shelf cavities, or have sea ice grow there...

Instructions for starting from rest

Step 1: run for 1 month from rest

  • In MOM_input set DT = 150, DT_THERM = 150
  • In input.nml set input_filename = 'n'
  • Change coupling timestep at corner of nuopc.runseq to also be 150
  • To save ICs, use SAVE_INITIAL_CONDS = True in MOM_input
  • do payu setup, payu sweep, payu run etc

Step 2: run for February

  • Comment out input.nml input_filename = 'n'
  • Change DT, DT_THERM and coupling timestep to be 400 (should work - otherwise try something in between eg 300)
  • You can also set DT_THERM to be larger, e.g. 800
  • Turn off IC saving with SAVE_INITIAL_CONDS = False in MOM_input
  • run - now you can use payu run -n XX
  • decrease walltime to 4 hours in config.yaml

Instructions for starting from a restart

  • Use payu checkout --restart path/to/restart (this should already be in the config.yaml)
  • Jan 1 1901 restart from this run is saved here: /g/data/ol01/cy8964/access-om3/restart/ice_shelf_panan-nancheck3-150925files-v2-notidalmix/restart012
  • E.g. 
    payu checkout dev-MC_4km_jra_ryf+regionalpanan+isf+draft --restart /g/data/ol01/cy8964/access-om3/restart/ice_shelf_panan-nancheck3-150925files-v2-notidalmix/restart012
  • Run - ensure DT is 400 (ish), input.nml has input_filename = 'n' commented out, CLOCK time in nuopc.runconfig is months

Other tips

  • If it crashes, drop the timestep - can check MOM CFL issues in work/log/ocn.log
  • Might find a resub script helpful - usually it takes about 5 segfaults straight after initialisation until it finally wants to run :( e.g. https://github.com/claireyung/access-om3-configs/blob/8km_jra_ryf_obc2-sapphirerapid-Charrassin-newparams-rerun-Wright-spinup-accessom2IC-yr9/resub.sh and add error: resub.sh run: rm -f resubmit.count to userscripts section of config.yaml