Refactor vertical coordinate computation in MPAS dynamical core

[kuanchihwang]

Tag name (required for release branches):

sima0_10_001 (Tentative)

Originator(s):

kuanchihwang

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

MPAS dynamical core uses height, denoted by $\zeta$, as the vertical coordinate system. In CAM-SIMA, the coordinate values are computed in the interface layer of MPAS dynamical core for history and physics initialization.

However, it can be argued that the vertical coordinate system should be considered an implementation detail of MPAS dynamical core, and that it should not concern CAM-SIMA. See Appendix "C.2 Vertical grid" in MPAS user guide for more information.

This PR refactors and relocates vertical coordinate computation to the subdriver layer of MPAS dynamical core. Now, CAM-SIMA just calls the appropriate procedures to get the coordinate values. Unit tests are added to ensure correctness.

This PR also ports a fix from CAM (ESCOMP/CAM#1095) to limit longitude values within the range of $[0, 2 \pi)$ according to MPAS mesh specifications.

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:

None

List all files added and what they do:

None

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

M       src/dynamics/mpas/driver/dyn_mpas_procedures.F90
  * Implement standardized procedures for computing vertical coordinates
M       src/dynamics/mpas/driver/dyn_mpas_subdriver.F90
  * Allow selective queries to mesh dimensions
  * Limit longitude values within the range of [0, 2 * pi)
M       src/dynamics/mpas/dyn_grid_impl.F90
  * Refactor reference height computation in terms of standardized procedures
M       src/dynamics/mpas/tests/unit/test_dyn_mpas_procedures.pf
  * Implement unit tests

Regression tests:

SMS_Ln9.mpasa480_mpasa480.FKESSLER.derecho_gnu.cam-outfrq_kessler_mpas_derecho (Overall: DIFF)
SMS_Ln9.mpasa480_mpasa480.FKESSLER.derecho_intel.cam-outfrq_kessler_mpas_derecho (Overall: DIFF)

Round-off errors due to limiting longitude values within the range of $[0, 2 \pi)$.

SMS_Ln9.ne3pg3_ne3pg3_mg37.FKESSLER.derecho_intel.cam-outfrq_se_cslam_multitape (Overall: NLFAIL)

Known failing test.

[nusbaume]

Thanks @kuanchihwang!