Update of P3 module

[hmorrison100]

TYPE: enhancement

KEYWORDS: P3, microphysics

SOURCE: Hugh Morrison (NCAR)

DESCRIPTION OF CHANGES:
Very minor changes only.

1. code comments
2. removal of debug check (non-answer-changing)
3. scaling of rain and ice evaporation/sublimation when the mass change from evap/sub is
   limited to prevent over- or under-shoots of saturation (answer changing, but negligible)
4. changed some arguments for the P3 initialization subroutine to optional
   (non-answer-changing).

LIST OF MODIFIED FILES:
phys/module_mp_p3.F

TESTS CONDUCTED:

1. Our standard test suite of cases for P3. Verified that simulation changes from the previous
   version are nonzero but negligible.
2. The modified codes are merged with develop and Release4.1.4 branches to include all the bug fixes we have. Regression test is done successfully as expected.
3. Test cases with mp_physics=50 and mp_physics=51 yield bit-for-bit results.

RELEASE NOTE: This version of P3 is designated as V3.1.14.

[smileMchen]

@hmorrison100
Hugh,
I wonder whether the p3_lookup_table_1.dat and p3_lookup_table_2.dat have been changed? If so, where can I get the new look-up tables?

[hmorrison100]

@hmorrison100
Hugh,
I wonder whether the p3_lookup_table_1.dat and p3_lookup_table_2.dat have been changed? If so, where can I get the new look-up tables?

Hi, the lookup tables haven't changed - they're the same as the last WRF release.

Thanks,
Hugh

[smileMchen]

@hmorrison100 @davegill @dudhia @weiwangncar
The modified P3 code from Hugh's folk is merged with Release4.1.4 to include all the bug fixes we have. Regression test is done successfully as expected.
I think this code is ready to be merged into the develop branch. Please review and approve.

[davegill]

@hmorrison100 @davegill @dudhia @weiwangncar
From the infrastructure perspective, I am OK with this PR.

1. It is to the right repo.
2. No conflicts.
3. The mods are entirely within the developer's scheme.
4. The argument lists are not changed (as above would imply).
5. Mostly clean up
6. I fixed the PR message

Still need Wei and Jimy to sign-off

[davegill]

@smileMchen
Ming,
Please update the PR with regtest info.

[smileMchen]

@davegill
Dave,
I post the message of regression test yesterday. It is done successfully.

[davegill]

@smileMchen

Dave,
I post the message of regression test yesterday. It is done successfully.

Ming,
Please post that information in the PR message.

[davegill]

@smileMchen

Ming,
Please post that information in the PR message.

Ming,
I see where that info is in the PR already - my bad.

[davegill]

@dudhia @weiwangncar @smileMchen
Folks,
I am OK with this PR from a infrastructure perspective.
Need Jimy and Wei for a sign-off

[davegill]

@dudhia @weiwangncar @smileMchen
Folks,
On this PR, we are waiting for a longer run.

[weiwangncar]

Differences in a model run would be beneficial to us to understand the change.