Optionally rotate wind/stress from to computational grid (from true north)

[mhrib]

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PR checklist

• [x ] Short (1 sentence) summary of your PR:
  Optional rotate wind vectors to computational grid (default)
• Developer(s):
  Mads Hvid Ribergaard, DMI
• 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.
  Able to merge. These branches can be automatically merged.
• How much do the PR code changes differ from the unmodified code?
  • [x ] bit for bit
  • different at roundoff level
  • more substantial
• Does this PR create or have dependencies on Icepack or any other models?
  • Yes
  • [x ] No
• Does this PR add any new test cases?
  • Yes
  • [ x] 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.)
  • [x ] Yes
  • No, does the documentation need to be updated at a later time?
    • Yes
    • No
• [x ] Please provide any additional information or relevant details below:

A completely other change within this pull request:

• Also printout seconds, if a reading error occur reading "hycom"-forcing within ice_forcing.F90

[apcraig]

How much testing has been done? Are we confident it's all bit-for-bit?

[eclare108213]

This is much easier to understand at a glance, thank you.

[mhrib]

@apcraig w.r.t. bit-for-bit. Depending on rotate_wind option (true/false) it will skip the rotation of wind/stress. So it assumes, that the provided forcing is rotated correctly and exactly like the default inline rotation.

[apcraig]

@mhrib I understand what the code is supposed to do. I just want to confirm that you have compiled and run this code, and that the default setting produces bit-for-bit results. That information was not included in the PR information yet. Thanks.

[mhrib]

@mhrib I understand what the code is supposed to do. I just want to confirm that you have compiled and run this code, and that the default setting produces bit-for-bit results. That information was not included in the PR information yet. Thanks.

@apcraig Sorry, I did not perform the test (which I always should do!). Now tested with intel compiler on GX3 grid (4x4) running for one day (24 steps) using the same ice_in file without rotate_wind defined (ie. set to default value = .true.): md5sum's on restart-files are equal.
fde1877b90dcc38e160d3ee1a520217c restart/iced.1998-01-02-00000.nc_new
fde1877b90dcc38e160d3ee1a520217c restart/iced.1998-01-02-00000.nc_org

[apcraig]

Thanks @mhrib, I also ran a full test suite last night and everything looks good. https://github.com/CICE-Consortium/Test-Results/wiki/cice_by_hash#3fedc78b1b012f8bd6c0fde7c1b41e79b9db63a9