Access alternative congelation ice formulation in icepack

[eclare108213]

• Short (1 sentence) summary of your PR:
  Provides namelist and brief documentation for new, alternative congelation ice formulation in Icepack,
  https://github.com/CICE-Consortium/Icepack/pull/494/files
• Developer(s):
  @eclare108213
• Suggest PR reviewers from list in the column to the right.
• Please copy the PR test results link or provide a summary of testing completed below.

base_suite comparison of the new code using default settings with the original code prior to modifications:

391 measured results of 391 total results
377 of 391 tests PASSED
2 of 391 tests PENDING
4 of 391 tests MISSING data
8 of 391 tests FAILED

The 8 failed tests are expected on chicoma (due to large processor counts; missing forcing data), and there are always 2 tests left in pending status when all have finished. The tests with missing data are the new ones for testing the congel_freeze='one-step' option.

QC testing was done comparing the 'two-step' and new 'one-step' option and this passed, see additional information below.

• How much do the PR code changes differ from the unmodified code?
  • bit for bit when congel_freeze = 'two-step' (default)
  • different at roundoff level
  • more substantial when congel_freeze = 'one-step'
• Does this PR create or have dependencies on Icepack or any other models?
  • Yes
  • No
• Does this PR update the Icepack submodule? If so, the Icepack submodule must point to a hash on Icepack's main branch.
  • Yes
  • No
• Does this PR add any new test cases?
  • Yes
  • No
• Is the documentation being updated? ("Documentation" includes information on the wiki or in the .rst files from doc/source/, which are used to create the online technical docs at https://readthedocs.org/projects/cice-consortium-cice/. A test build of the technical docs will be performed as part of the PR testing.)
  • Yes
  • No, does the documentation need to be updated at a later time?
    • Yes
    • No
• Please document the changes in detail, including why the changes are made. This will become part of the PR commit log.

Add support for 'one-step' congelation ice formation in addition to current default 'two-step' option. Added a new namelist, congel_freeze to control the congelation option. This CICE update requires an update to Icepack to support the new congel_freeze option. The default setting for congel_freeze is set to 'two-step' for backwards compatibility. The new 'one-step' option will be evaluated and may become the default option in the future.

Testing indicates the default setting is bit-for-bit identical with the current main.

[apcraig]

I ran a QC test and it passed. This is what I did. Using derecho, intel, and 128 cores. I checked out the current main branch of Icepack and CICE and then merged in the icongel and congel branches. I then setup two qc cases, one with "one-step", the other with "two-step". The congel_freeze namelist was the only difference. I attach the images. "qc1" is one-step, "qc2" is two-step.

./cice.t-test.py $WORKDIR/CICE_RUNS/derecho_intel_smoke_gx1_128x1_medium_qc.qc1s $WORKDIR/CICE_RUNS/derecho_intel_smoke_gx1_128x1_medium_qc.qc2s
INFO:__main__:Running QC test on the following directories:
INFO:__main__:  /glade/derecho/scratch/tcraig/CICE_RUNS/derecho_intel_smoke_gx1_128x1_medium_qc.qc1s
INFO:__main__:  /glade/derecho/scratch/tcraig/CICE_RUNS/derecho_intel_smoke_gx1_128x1_medium_qc.qc2s
INFO:__main__:Number of files: 1825
INFO:__main__:2 Stage Test Passed
INFO:__main__:Quadratic Skill Test Passed for Northern Hemisphere
INFO:__main__:Quadratic Skill Test Passed for Southern Hemisphere
INFO:__main__:Creating map of the data (ice_thickness_derecho_intel_smoke_gx1_128x1_medium_qc.qc1.png)
INFO:__main__:Creating map of the data (ice_thickness_derecho_intel_smoke_gx1_128x1_medium_qc.qc2.png)
INFO:__main__:Creating map of the data (ice_thickness_derecho_intel_smoke_gx1_128x1_medium_qc.qc1_minus_derecho_intel_smoke_gx1_128x1_medium_qc.qc2.png)
INFO:__main__:
INFO:__main__:Quality Control Test PASSED

[apcraig]

The two-step is the old implementation. One-step is the new and improved implementation. Do we want to make congel_freeze='one-step' the default?

[dabail10]

Let me test it in coupled first.

[apcraig]

Should we merge this week with old 'two-step' default then update the default next week or after if we gain confidence?

[dabail10]

What happened with the gh-actions? I am happy to merge this with two-step as the default.

[apcraig]

What happened with the gh-actions? I am happy to merge this with two-step as the default.

We need to merge the Icepack PR first, then update this PR which depends on it. Then GH actions should be OK. I will merge take care of those steps now and we can decide if we want to move away from two-step as the default later.

[apcraig]

I just updated the Icepack version on this branch/PR. This should be ready to merge, will do some additional checks and wait for GH actions to run.

[apcraig]

I updated the PR documentation and this PR should be ready to merge. @eclare108213, @dabail10, let me know if there are any concerns. Otherwise I'll merge before the weekend.

[anton-seaice]

Thanks for this @eclare108213 and @apcraig - I agree we shouldn't change the default.

[eclare108213]

I also agree, we should leave the default as 'two-step' until at least one of the modeling centers has a chance to evaluate the change in a coupled system. This PR is ready to merge. Thanks @apcraig for your help!