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The official repository for the Weather Research and Forecasting (WRF) model
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Syncing MYNN-EDMF + bug fix #1996

Closed joeolson42 closed 5 months ago

joeolson42 commented 5 months ago

Syncing MYNN-EDMF + bug fixes

TYPE: bug fix, enhancement

KEYWORDS: subgrid clouds, mass flux, local diffusion

SOURCE: Joseph Olson and Laura Fowler

DESCRIPTION OF CHANGES: Problems:

  1. bug fix for momentum transport - minor impact
  2. underdiffusive in very stable conditions, especially high latitudes. This reveals itself as a cold bias at high latitudes in RRFS and the TKE is too often hitting the lower limit.
  3. cosmetic issue with cloud fractions in unsaturated grid cells with nonzero mixing ratios
  4. uninitialized scalars in unused subroutine planned for deletion

Solutions (1-1 mapping with problems listed above):

  1. added the missing rho to the mass flux components in the u and v tridiagonal vectors.
  2. reverted the blending of the mixing lengths to same as HRRRv4 and tweaked some parameters to slightly increase the diffusion, mostly isolated to very stable conditions.
  3. relaxed some limits and combined the ice and snow cloud fraction check together.
  4. replaced uninitialized variables with variables that are initialized (changed names). Still plan to remove this subroutine after the downdrafts are fully revised (very close).

LIST OF MODIFIED FILES: list of changed files (use git diff --name-status master to get formatted list) phys/module_bl_mynn.F

TESTS CONDUCTED:

Do mods fix problem? (1) Yes, (2) alleviated, (3) Yes, (4) Yes. Single case studies were performed. Full retrospective tests are ongoing. All physics changes hav a small impact. Are the Jenkins tests all passing? RELEASE NOTE: This commit is just a minor update, probably not worthy of mention in the release notes. If anything is interesting, it can be added to the release note for PR-1938.

weiwangncar commented 5 months ago

The regression test results:

Test Type              | Expected  | Received |  Failed
= = = = = = = = = = = = = = = = = = = = = = = =  = = = =
Number of Tests        : 23           24
Number of Builds       : 60           57
Number of Simulations  : 158           150        0
Number of Comparisons  : 95           86        0

Failed Simulations are: 
None
Which comparisons are not bit-for-bit: 
None