1 of 8

CCPP Physics

08/02/2023

2 of 8

Agenda

  • Code management for schemes that various hosts want to use and develop
    • Current focus: Tiedtke convection
  • What we heard in the last meeting about 3D physics
    • Presented by Jimy Dudhia (slides)

2

3 of 8

Code Mgmt for Distro Dev

The Tiedtke example

3

Disclaimer: this is a best effort in collecting the info. Please chime in if something is incorrect

4 of 8

Current Status of Tiedtke (1989+) Convection - 1

  • There has been a Tiedtke convection scheme in CCPP for years
    • Contributed by Chunxi Zhang, then at OU
    • Current PoCs: Jongil Han and Qingfu Liu (EMC)
    • Used for UFS research and NRL/NEPTUNE pre-implementation tests
    • It has not been maintained/updated in years, not part of any RT
      • It is in working order since experiments have been conducted recently
    • Origin of the code is unclear
      • I (Ligia) thought it was coded from a paper
      • Jim/Matus let us know it was coded from the extensive ECMWF documentation
      • Recent investigation shows the code is similar to Open IFS
      • Someone said it came from a community Reg Climate model via Chunxi then at U Hawaii

4

There is also Tiedtke scheme used by Lisa Bengtsson. She obtained code directly from Open IFS

5 of 8

Current Status of Tiedtke (1989+) Convection - 2

  • There has been a Tiedtke scheme in WRF since 2010 (MPAS only recently)
    • 2014: Updated to new Tiedtke “Based on the document for the Integrated Forecasting System (IFS) Cy40r1, European Centre for Medium-Range Weather Forecasts (ECMWF 2014)
      • Implemented in the WRF Model by Zhang and Wang (2017)
    • 2016: WRF update from U. Hawaii
    • There are scale-aware updates in MPAS v8 by Wei Wang (NCAR MMM) (Wang 2022)
  • Matus Martini (NRL) wants the MPAS updates in CCPP for NEPTUNE
    • Submitted issue and PR
  • EMC and HRD (HAFS) also interested

5

6 of 8

​

Meanwhile, also happening

  • NCAR MMM has a “Shared Physics Repo” (private repo)
    • CCPP-compliant physics for WRF, MPAS, and CM1
    • MMM has put the MPAS v8 code in this repo
    • DTC has experimental work in which this repo is used as a submodule to the authoritative CCPP
  • Jimy compared Wei’s code vs Matus code and noted differences
    • Jimy asked to wait to review/commit the PR until Wei returns in September

6

7 of 8

​

Goals and Way Forward

  • Goals
    • End up with one Tiedtke convection code
      • Code can be wherever. Host can pull from various repos (submodules etc.)
    • Enable EMC, NRL, NCAR to conduct the runs they need
    • Keep code used in experiments in the authoritative repo
      • Allows tracking and provenance of experiments
      • Foster collaborations
  • Way Forward
    • Option 1: Proceed with review and merge of Matus’ PR
      • Pros: Follows process, involves official PoCs, EMC interested in updates too
      • Cons: Possibly get second round of updates later after Wei returns
    • Option 2: Delay PR review until Wei is back
      • Pros: Benefits from Wei’s review
      • Potential cons
        • Slow scientific and technical progress
        • Experiments are being conducted with code that is not available for others to review/track

7

8 of 8

​

A Few Other Things

  • Is there a restriction from ECMWF wrt using the Tiedtke scheme for operational use?
  • Matus’ PR is directed to the CCPP Physics main repo
    • This seems appropriate for a NRL contribution
    • It will later be synced to the UFS Fork for that community to use

8