Add regression tests to generate/check baselines for individual physics schemes

[jimmielin]

What is the feature/what would you like to discuss?

Currently the SIMA regression tests (Derecho/GNU) run individual scheme SDFs, but they only compare against existing CAM snapshots. Some of these tests, e.g., CAM4 schemes (Hack, RK) also have user namelist mods as the snapshots are generated from QPC4.

During the review of #377, @cacraigucar proposed adding another set of tests (without namelist mods) that create baselines (instead of using the ncdata_check functionality) that can be compared when SIMA is tagged to capture any changes that affect individual physics schemes.

@cacraigucar originally wrote:

Perhaps we need two tests

1. A test which compares directly with CAM and uses these custom settings
2. A test which does not use the custom settings, but is used to maintain BFB testing of RK over future commits, using the values supplied by CAM-SIMA.

and also:

I would suggest that the baseline which gets stored from this tests depend on the settings in that structure. That way if the field gets changed, then the test will have a baseline difference indicating that this routine has been impacted. I've not checked the other values below, but I believe that all of them specified in physconst should not be listed (changed or unchanged)

During the Monday hackathon we agreed to add these tests for the CAM4 physics schemes (Hack, RK, HB ...) after the CAM4 physics schemes are close to being finalized.

I'll self-assign this issue to me so these tests can be added when I'm close to being ready...

Is there anyone in particular you want to be part of this conversation?

@cacraigucar @nusbaume @peverwhee @mwaxmonsky

Will this change (regression test) answers?

Yes

Will you be implementing this enhancement yourself?

Yes