Fix outgoing lw for history and coupling.

[dabail10]

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PR checklist

• Short (1 sentence) summary of your PR:
  A bug was identified when a grid cell goes from ice free to ice covered. Issue flwout set to zero at ice free points #994
• Developer(s):
  dabail10 (D. Bailey)
• 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.
  https://github.com/CICE-Consortium/Test-Results/wiki/cice_by_hash_forks#6aa677ec49b415298b6368a19e5122f9c9d49f8e
• How much do the PR code changes differ from the unmodified code?
  • bit for bit
  • different at roundoff level
  • more substantial
• 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.
  This is a two-line change in ice_flux.F90 (scale_fluxes) to check for the condition where aice > ), but flwout > -puny. This means the cell was ice free at the beginning of the step, but non-zero at the end. It sets the outgoing longwave to the open ocean value based on the freezing temperature. This is bfb, but will change the history output of flwup and flwup_ai. Test results are coming.

[dabail10]

Here are the test results:

https://github.com/CICE-Consortium/Test-Results/wiki/cice_by_hash_forks#6aa677ec49b415298b6368a19e5122f9c9d49f8e

[anton-seaice]

If its ok, ill defer to Tony and Elizabeth on this. ACCESS don't use this field.

[dabail10]

If its ok, ill defer to Tony and Elizabeth on this. ACCESS don't use this field.

Really? Was does the atmosphere component use for the upward longwave computation?

[anton-seaice]

Its calculated internally in the atmosphere - presumably in the same way CICE is calculating it