sima0_14_003: Update MPAS dynamical core to version 8.4.0 by kuanchihwang · Pull Request #495 · ESCOMP/CAM-SIMA

kuanchihwang · 2026-04-24T19:09:31Z

Tag name (required for release branches)

sima0_14_003

Originator(s)

kuanchihwang

Description (include the issue title, and the keyword ['closes', 'fixes', 'resolves'] followed by the issue number)

This PR updates MPAS dynamical core from version 8.3.1 to 8.4.0. See the release notes for details.

Notably, the new Large Eddy Simulation (LES) capability in MPAS is experimentally supported under CAM-SIMA, at the price of increased complexity in constituent handling. However, due to the object-oriented design of MPAS subdriver, this complexity is entirely contained within the subdriver layer and does not affect other parts of CAM-SIMA. This capability is disabled by default, and can be enabled manually through namelist options.

A future PR is planned to refactor the dyn_mpas_define_scalar subroutine in MPAS subdriver to keep its complexity and scope in check.

Describe any changes made to the build system

src/dynamics/mpas/assets/Makefile.in.CESM has been modified to suppress harmless but potentially confusing errors in build logs.

Describe any changes made to the namelist

mpas_epssm

This namelist option has been deprecated and set to 0.0. Setting it to any values other than 0.0 triggers a compatibility warning.

mpas_epssm_maximum, mpas_epssm_minimum, mpas_epssm_transition_bottom_z, mpas_epssm_transition_top_z

These new namelist options provide more fine-grained control on the off-centering parameter for the vertically implicit acoustic integration.

mpas_gpu_aware_mpi

Whether to use GPU-aware MPI for halo exchanges.

mpas_les_model, mpas_les_surface, mpas_mix_scalars, mpas_surface_drag_coefficient, mpas_surface_heat_flux, mpas_surface_moisture_flux

These new namelist options control the new LES capability in MPAS.

List any changes to the defaults for the input datasets (e.g., boundary datasets)

None

List all files eliminated and why

None

List all files added and what they do

A       src/dynamics/mpas/assets/0001-Fix-Fortran-standard-violation.patch
A       src/dynamics/mpas/assets/0002-Add-missing-argument-intent.patch
A       src/dynamics/mpas/assets/0003-Avoid-implicit-save-attribute.patch
  * Add patches to fix crash in MPAS 8.4.0

List all existing files that have been modified, and describe the changes

M       .gitmodules
M       src/dynamics/mpas/dycore
  * Update MPAS dynamical core to version 8.4.0
M       src/dynamics/mpas/assets/generate_namelist_definition.py
M       src/dynamics/mpas/namelist_definition_mpas_dycore.xml
  * Update namelist definition file and script for MPAS dynamical core
M       src/dynamics/mpas/assets/Makefile.in.CESM
  * Suppress harmless errors in build logs
M       src/dynamics/mpas/driver/dyn_mpas_subdriver.F90
  * Remove deprecated variables that no longer exist
  * Rework constituent handling in MPAS subdriver to support new LES capability

Regression tests

derecho/aux_sima_gnu

SMS_D_Ln9.mpasa120_mpasa120.QPC4.derecho_gnu.cam-outfrq_analy_ic_cam4 (Overall: DIFF) details:
  FAIL SMS_D_Ln9.mpasa120_mpasa120.QPC4.derecho_gnu.cam-outfrq_analy_ic_cam4 NLCOMP
  FAIL SMS_D_Ln9.mpasa120_mpasa120.QPC4.derecho_gnu.cam-outfrq_analy_ic_cam4 BASELINE /glade/campaign/cesm/community/amwg/sima_baselines/latest_gnu: DIFF
SMS_Ln9.mpasa120_mpasa120.QPC4.derecho_gnu.cam-outfrq_analy_ic_cam4 (Overall: DIFF) details:
  FAIL SMS_Ln9.mpasa120_mpasa120.QPC4.derecho_gnu.cam-outfrq_analy_ic_cam4 NLCOMP
  FAIL SMS_Ln9.mpasa120_mpasa120.QPC4.derecho_gnu.cam-outfrq_analy_ic_cam4 BASELINE /glade/campaign/cesm/community/amwg/sima_baselines/latest_gnu: DIFF
SMS_Ln9.mpasa480_mpasa480.FKESSLER.derecho_gnu.cam-outfrq_kessler_mpas_derecho (Overall: DIFF) details:
  FAIL SMS_Ln9.mpasa480_mpasa480.FKESSLER.derecho_gnu.cam-outfrq_kessler_mpas_derecho NLCOMP
  FAIL SMS_Ln9.mpasa480_mpasa480.FKESSLER.derecho_gnu.cam-outfrq_kessler_mpas_derecho BASELINE /glade/campaign/cesm/community/amwg/sima_baselines/latest_gnu: DIFF
SMS_Ln9.mpasa480_mpasa480.FKESSLER.derecho_gnu.cam-outfrq_kessler_mpas_derecho_history (Overall: DIFF) details:
  FAIL SMS_Ln9.mpasa480_mpasa480.FKESSLER.derecho_gnu.cam-outfrq_kessler_mpas_derecho_history NLCOMP
  FAIL SMS_Ln9.mpasa480_mpasa480.FKESSLER.derecho_gnu.cam-outfrq_kessler_mpas_derecho_history BASELINE /glade/campaign/cesm/community/amwg/sima_baselines/latest_gnu: DIFF

Expected answer changes due to MPAS version update.

SMS_Ln9.ne3pg3_ne3pg3_mg37.FADIAB.derecho_gnu.cam-outfrq_se_cslam (Overall: FAIL) details:
  FAIL SMS_Ln9.ne3pg3_ne3pg3_mg37.FADIAB.derecho_gnu.cam-outfrq_se_cslam RUN time=9

Known failing test.

derecho/aux_sima_intel

SMS_D_Ln9.mpasa120_mpasa120.QPC4.derecho_intel.cam-outfrq_analy_ic_cam4 (Overall: DIFF) details:
  FAIL SMS_D_Ln9.mpasa120_mpasa120.QPC4.derecho_intel.cam-outfrq_analy_ic_cam4 NLCOMP
  FAIL SMS_D_Ln9.mpasa120_mpasa120.QPC4.derecho_intel.cam-outfrq_analy_ic_cam4 BASELINE /glade/campaign/cesm/community/amwg/sima_baselines/latest_intel: DIFF
SMS_Ln9.mpasa120_mpasa120.QPC4.derecho_intel.cam-outfrq_analy_ic_cam4 (Overall: DIFF) details:
  FAIL SMS_Ln9.mpasa120_mpasa120.QPC4.derecho_intel.cam-outfrq_analy_ic_cam4 NLCOMP
  FAIL SMS_Ln9.mpasa120_mpasa120.QPC4.derecho_intel.cam-outfrq_analy_ic_cam4 BASELINE /glade/campaign/cesm/community/amwg/sima_baselines/latest_intel: DIFF
SMS_Ln9.mpasa480_mpasa480.FKESSLER.derecho_intel.cam-outfrq_kessler_mpas_derecho (Overall: DIFF) details:
  FAIL SMS_Ln9.mpasa480_mpasa480.FKESSLER.derecho_intel.cam-outfrq_kessler_mpas_derecho NLCOMP
  FAIL SMS_Ln9.mpasa480_mpasa480.FKESSLER.derecho_intel.cam-outfrq_kessler_mpas_derecho BASELINE /glade/campaign/cesm/community/amwg/sima_baselines/latest_intel: DIFF
SMS_Ln9.mpasa480_mpasa480.FKESSLER.derecho_intel.cam-outfrq_kessler_mpas_derecho_history (Overall: DIFF) details:
  FAIL SMS_Ln9.mpasa480_mpasa480.FKESSLER.derecho_intel.cam-outfrq_kessler_mpas_derecho_history NLCOMP
  FAIL SMS_Ln9.mpasa480_mpasa480.FKESSLER.derecho_intel.cam-outfrq_kessler_mpas_derecho_history BASELINE /glade/campaign/cesm/community/amwg/sima_baselines/latest_intel: DIFF

Expected answer changes due to MPAS version update.

SMS_Ln9.ne3pg3_ne3pg3_mg37.FKESSLER.derecho_intel.cam-outfrq_se_cslam_multitape (Overall: NLFAIL) details:
  FAIL SMS_Ln9.ne3pg3_ne3pg3_mg37.FKESSLER.derecho_intel.cam-outfrq_se_cslam_multitape NLCOMP

Known failing test.

derecho/aux_sima_nvhpc

Pass.

The patches are being contributed to upstream MPAS. We have to keep them for now until the next MPAS release.

…bility

nusbaume

Thanks for bringing in the latest version of MPAS @kuanchihwang! I have a question, an optional clean-up request, and some requests to eventually provide some unit labels for MPAS namelist entries, but nothing that is strictly required for this particular PR.

Of course if you have any questions or concerns with any of my requests then just let me know. Thanks again!

$ python3 generate_namelist_definition.py -r <path-to>/Registry.xml -n <path-to>/namelist_definition_mpas_dycore.xml -s <path-to>/entry_id_pg.xsd Generated <path-to>/namelist_definition_mpas_dycore.xml Successfully validated <path-to>/namelist_definition_mpas_dycore.xml against <path-to>/entry_id_pg.xsd

kuanchihwang added 6 commits April 24, 2026 12:29

Update MPAS dynamical core to version 8.4.0

d59713d

Suppress harmless errors in build logs

e87d52c

Add patches to fix crash in MPAS 8.4.0

93d5b89

The patches are being contributed to upstream MPAS. We have to keep them for now until the next MPAS release.

Update namelist definition file and script for MPAS dynamical core

3554b36

Remove deprecated variables that no longer exist

85af071

Rework constituent handling in MPAS subdriver to support new LES capa…

353430c

…bility

kuanchihwang temporarily deployed to CI-tests-on-CIRRUS April 24, 2026 19:09 — with GitHub Actions Inactive

kuanchihwang marked this pull request as ready for review April 24, 2026 19:17

kuanchihwang requested review from mgduda and nusbaume April 24, 2026 19:19

Merge branch 'development' into develop/mpas-dycore-8.4.0

a7ed1d9

kuanchihwang temporarily deployed to CI-tests-on-CIRRUS May 1, 2026 20:01 — with GitHub Actions Inactive

nusbaume approved these changes May 12, 2026

View reviewed changes

Merge branch 'development' into develop/mpas-dycore-8.4.0

2c49409

kuanchihwang had a problem deploying to CI-tests-on-CIRRUS May 18, 2026 21:21 — with GitHub Actions Error

kuanchihwang added 3 commits May 18, 2026 15:45

Promote les_model logical to component of mpas_dynamical_core_type

9aa07d6

Output units elements when generating MPAS namelist definition file

6d63e60

kuanchihwang temporarily deployed to CI-tests-on-CIRRUS May 19, 2026 01:42 — with GitHub Actions Inactive

nusbaume requested a review from peverwhee June 1, 2026 17:20

Merge branch 'development' into develop/mpas-dycore-8.4.0

663e5e5

kuanchihwang temporarily deployed to CI-tests-on-CIRRUS June 1, 2026 17:31 — with GitHub Actions Inactive

peverwhee approved these changes Jun 2, 2026

View reviewed changes

Merge branch 'development' into develop/mpas-dycore-8.4.0

b2baaa3

kuanchihwang changed the title ~~Update MPAS dynamical core to version 8.4.0~~ sima0_14_003: Update MPAS dynamical core to version 8.4.0 Jun 4, 2026

kuanchihwang temporarily deployed to CI-tests-on-CIRRUS June 5, 2026 18:43 — with GitHub Actions Inactive

kuanchihwang merged commit cb52c4d into ESCOMP:development Jun 5, 2026
23 checks passed

kuanchihwang deleted the staging/mpas-dycore-8.4.0 branch June 5, 2026 19:14

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sima0_14_003: Update MPAS dynamical core to version 8.4.0#495

sima0_14_003: Update MPAS dynamical core to version 8.4.0#495
kuanchihwang merged 13 commits into
ESCOMP:developmentfrom
kuanchihwang:staging/mpas-dycore-8.4.0

kuanchihwang commented Apr 24, 2026 •

edited

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kuanchihwang commented Apr 24, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Tag name (required for release branches)

Originator(s)

Description (include the issue title, and the keyword ['closes', 'fixes', 'resolves'] followed by the issue number)

Describe any changes made to the build system

Describe any changes made to the namelist

List any changes to the defaults for the input datasets (e.g., boundary datasets)

List all files eliminated and why

List all files added and what they do

List all existing files that have been modified, and describe the changes

Regression tests

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kuanchihwang commented Apr 24, 2026 •

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