WDM scheme minor bug fixes

[dudhia]

TYPE: bug fix

KEYWORDS: WDM5, WDM6, WDM7

SOURCE: Kyo-Sun Lim (Kyungpook National University) and Sooya Bae (KIAPS).

DESCRIPTION OF CHANGES:
Error correction based on Lei et al. (JGR, 2020)

1. Melting of snow/graupel :
   -Problem: melting processes of snow/graupel mass and number concentration do not occur
   at the same time.
   -Correction: melting of snow/graupel changes the snow/graupel/rain mass and rain number
   concentration at the same time.
   -Effect: Generation of rain number concentrations would decrease.
2. Regeneration of CCN number concentration due to the cloud water evaporation:
   -Problem: Cloud water number concentration does not add into the CCN number concentration.
   -Correction: Adding the cloud water number concentration into the CCN number concentration.

• Effect: CCN number concentration would increase.

ISSUE: none

LIST OF MODIFIED FILES:
module_mp_wdm5.F
module_mp_wdm6.F
module_mp_wdm7.F

TESTS CONDUCTED:
Passed Jenkins
WDM6 tested versus master. Diffs small for surface fields including rainfall after 12 hrs of June 2001 test case (shown).

RELEASE NOTE: Melting of snow/graupel now changes the snow/graupel/rain mass and rain number concentration at the same time in all WDM schemes, provided by Kyo-Sun Lim (Kyunpook National University, South Korea).

[weiwangncar]

@dudhia Can we see some differences in a model run?

[dudhia]

I asked if they have any images.

…

On Thu, Jan 23, 2020 at 11:48 AM weiwangncar ***@***.***> wrote: @dudhia <https://github.com/dudhia> Can we see some differences in a model run? — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#1057?email_source=notifications&email_token=AEIZ77FD5AZWWUQOMKWCE3DQ7HRAVA5CNFSM4KKMIIVKYY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOEJYNMDY#issuecomment-577820175>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AEIZ77H3JJD65FV2TUOJ46TQ7HRAVANCNFSM4KKMIIVA> .

[davegill]

@dudhia
Jimy,
Would you add their affiliations

[davegill]

@dudhia
Jimy,
Please update the "regression test" comment in the commit message.

[dudhia]

Not sure where Sunny works now. Sooya was at KIAPS, not sure now.

[davegill]

@weiwangncar @dudhia
Folks,
The fixes seem simple and consistent. Before my approval, we are still waiting on:

1. Inclusion of requested imagery for PR message.
2. Proper affiliations of contributors. Maybe Hong knows?

[weiwangncar]

@dudhia I guess to most users, what impact these changes have to surface precipitation would be of some interest. Do we know? Can we get a statement from the contributors?