Enable MPAS dynamical core to compute relative vorticities at cell points

[kuanchihwang]

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Originator(s):

kuanchihwang

Descriptions (include the issue title, and the keyword ['closes', 'fixes', 'resolves'] followed by the issue number):

This PR ports a new feature from ESCOMP/CAM#1297 to CAM-SIMA. It enables MPAS dynamical core to compute relative vorticities at cell points. Although the feature is currently not used anywhere, it will be when CAM7 physics is implemented in CAM-SIMA.

The formulations are identical to CAM, but the implementation here incorporates object-oriented programming to be consistent with other parts of MPAS dynamical core.

Describe any changes made to the build system:

None

Describe any changes made to the namelist:

None

List any changes to the defaults for the input datasets (e.g., boundary datasets):

None

List all files eliminated and why:

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List all files added and what they do:

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List all existing files that have been modified, and describe the changes:

M       src/dynamics/mpas/driver/dyn_mpas_subdriver.F90
  * Enable MPAS subdriver to compute relative vorticities at cell points

Regression tests:

No changes to any existing tests. All tests pass with respect to the last baseline, sima0_06_000.

[nusbaume]

Thanks again @kuanchihwang! Just had one general comment (but it doesn't require any changes to this particular PR).

[nusbaume]

Just an FYI that we have started trying to provide the Fortran-provided error message from allocate statements as well, e.g.:

character(256) :: errmsg
...
allocate(cell_relative_vorticity(nvertlevels, ncellssolve), stat=ierr, errmsg=errmsg)

Of course this change certainly isn't required for this PR.

[kuanchihwang]

Yes, I have noticed it in recent PR reviews. I will open a dedicated PR to implement this enhancement.