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E3SM-Project / E3SM

Energy Exascale Earth System Model source code. NOTE: use "maint" branches for your work. Head of master is not validated.
https://docs.e3sm.org/E3SM
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Major MMF2/PAM updates #6354

Open whannah1 opened 4 weeks ago

whannah1 commented 4 weeks ago

This brings in several updates and fixes for the PAM CRM used in the MMF2 compsets to improve stability and throughput. Some of these required updates to the PAM submodule, but the most important change was the addition of adaptive sub-cycling in the PAM driver. This change allowed the CRM time step to be increased to 10 seconds, which dramatically improved the throughput while also making the model much more resilient to numerically unstable conditions due to unrealistically strong velocities (still not sure why these occur in the first place).

other notable changes for PAM and/or the driver:

Fixes #6363

[non-BFB] only for MMF2

github-actions[bot] commented 4 weeks ago

PR Preview Action v1.4.7 :---: :rocket: Deployed preview to https://E3SM-Project.github.io/E3SM/pr-preview/pr-6354/ on branch gh-pages at 2024-04-25 19:48 UTC

whannah1 commented 4 weeks ago

The plot below shows various 1-year averages from a recent simulation on OLCF Summit. This run had an average throughput of 1.57 sypd using 128 nodes.

Note that the liquid and ice water paths fields show a substantial imbalance of too little liquid and too much ice. This needs to be addressed with tuning parameters in the future. The main parameters we want to target are not available to be modified from the MMF/PAM code until the EAMXX fork is pulled into the E3SM repo. So tuning changes are expected to be the focus of a future PR.

image

whannah1 commented 3 weeks ago

The latest commit should address issue #6363