ctsm5.4.000

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Tag name: ctsm5.4.000
Originator(s): slevis (Samuel Levis,UCAR/TSS), ekluzek (Erik Kluzek,UCAR/TSS)
Date: Thu Dec 4 12:15:31 PM MST 2025
One-line Summary: Merge alpha-ctsm5.4.CMIP7 to master

Purpose and description of changes
----------------------------------

Merging alpha-ctsm5.4.CMIP7 to master in preparation for the official ctsm5.4 release.

WhatsNewInCTSM5.4.md documents the updates from ctsm5.3.021 (the official ctsm5.3 release) to present and will be updated with the exact ctsm5.4 release tag in the near future, once we identify such tag.

Here we summarize updates from ctsm5.3.085 (the most recent tag) to ctsm5.4.000 (the current tag):
- Updating ALL the fsurdat/landuse files to version ctsm5.4, though this version is backwards compatible with ctsm5.3 datasets, so ctsm5.3 files can still be used.
- Updating "agricultural fire peak month" raw dataset, as well as the algorithm determining this field's dominant values in mksurfdata_esmf
- Future scenarios are done using the cmip6 ctsm5.3 surface datasets. The new XML variable CLM_CMIP_ERA controls this.
- A few other updates come in as well for clm6_0:
* New Initial Condition (IC) files
* New parameter file
* New crop calendar datasets
* Changes to fire parameters along with new fire_method "li2024crujra"
* New population density file

Contributors: Sam Levis @slevis-lmwg, Peter Lawrence @lawrencepj1, Erik Kluzek @ekluzek, Will Wieder @wwieder, Keith Oleson @olyson, Sam Rabin @samsrabin, Fang Li @lifang0209

Significant changes to scientifically-supported configurations
--------------------------------------------------------------

Does this tag change answers significantly for any of the following physics configurations?
(Details of any changes will be given in the "Answer changes" section below.)

[Put an [X] in the box for any configuration with significant answer changes.]

[X] clm6_0

[X] clm5_0

[X] ctsm5_0-nwp

[X] clm4_5


Bugs fixed
----------
List of CTSM issues fixed (include CTSM Issue # and description) [one per line]:
Resolves #2851 Update to CMIP7 LULCC forcings (umbrella issue with the main ctsm5.4 checklist)

Notes of particular relevance for users
---------------------------------------
Caveats for users (e.g., need to interpolate initial conditions):
The new ctsm5.4 fsurdat/flanduse_timeseries datasets are used by default, but the model will work with previous ctsm5.3 datasets. The new initial conditions (finidat) for clm6_0 will work without having to interpolate them. The initial conditions for previous physics (so previous finidat files you've been using) do need to be interpolated (so add use_init_interp=TRUE to user_nl_clm).

Changes to CTSM's user interface (e.g., new/renamed XML or namelist variables):
New XML variable: CLM_CMIP_ERA (can be cmip6 or cmip7)
Defaults to cmip7 except for the SSP scenarios which use cmip6

Changes made to namelist defaults (e.g., changed parameter values):
init_interp_fill_missing_urban_with_HD is set to TRUE all of the time even when not needed

Fire parameters update: (li2024gswp3, and li2024crujra fire_method):
- defo_fire_precip_thresh_bet
- cli_scale
- cropfire_a1

Changes to the datasets (e.g., parameter, surface or initial files):
New fsurdat/landuse files
For clm6: New paramfile, finidat files, crop calendar datasets, population density stream file

Changes to documentation:
Updates about history files splitting into separate non-instantaneous and instantaneous files

Notes of particular relevance for developers:
---------------------------------------------
Caveats for developers (e.g., code that is duplicated that requires double maintenance):
ccs_config points to temporary tag ccs_config_cesm1.0.61_add_domain_ne3np4.pg2_1 to allow use of a new grid. The temporary tag will get replaced appropriately in the next merge of b4b-dev to master.

fsurdat/landuse files are associated with a cmip_era flag in namelist_defaults to describe if it's a cmip6 or cmip7 version.

Changes to tests or testing:
The ctsm_sci test-suite now includes new tests for a few newly introduced grids.

Testing summary:
----------------
[PASS means all tests PASS; OK means tests PASS other than expected fails.]

build-namelist tests (if CLMBuildNamelist.pm has changed):

derecho - OK

Also namelist comparisons as outlined here:
https://github.com/ESCOMP/CTSM/wiki/Minor-Version-Update-Protocols#namelist-validation
We compared against ctsm5.3.021 namelists, i.e. against the ctsm5.3 release tag

python testing (if python code has changed; see instructions in python/README.md; document testing done):

derecho - PASS

regular tests (aux_clm: https://github.com/ESCOMP/CTSM/wiki/System-Testing-Guide#pre-merge-system-testing):
derecho ----- OK
izumi ------- OK

fates tests compared to fates-sci.1.88.0_api.42.0.0-ctsm5.3.083 on derecho and fates-sci.1.88.0_api.41.0.0-ctsm5.3.082 on izumi
derecho ----- OK
izumi ------- OK

ctsm_sci compared to ctsm_sci-alpha-ctsm5.4.CMIP7.19.ctsm5.3.082
derecho ---- OK

mosart tests compared to mosart1.1.12-ctsm5.3.066
derecho ----- OK
izumi ------- OK

rtm tests compared to rtm1_0_89-ctsm5.3.065
derecho ----- OK
izumi ------- OK

mksurfdata_esmf
derecho ----- OK tested a single resolution for b4b with different number of cpus; ran "make all" to create all datasets (completes in 6 hours, longest mksrf_crop-global-hist-low-res)

fsurdat verification
derecho ----- OK validate_fsurdat_files.sh script added in tools/mksurfdata_esmf

Answer changes
--------------

Changes answers relative to baseline: Yes

Summarize any changes to answers, i.e.,
- what code configurations: All
- what platforms/compilers: All
- nature of change: larger than roundoff/same climate; possibly new climate in clm6

If this tag changes climate describe the run(s) done to evaluate the new
climate (put details of the simulations in the experiment database)
- https://github.com/NCAR/LMWG_dev/issues/123
- https://github.com/NCAR/LMWG_dev/issues/124
- https://github.com/NCAR/LMWG_dev/issues/125
- https://github.com/NCAR/LMWG_dev/issues/126
- https://github.com/NCAR/LMWG_dev/issues/127

Other details
-------------
List any git submodules updated (cime, rtm, mosart, cism, fates, etc.):
ccs_config_cesm1.0.61 to ccs_config_cesm1.0.61_add_domain_ne3np4.pg2_1 as explained in "Caveats for developers" above

Pull Requests that document the changes (include PR ids):
https://github.com/ESCOMP/ctsm/pull/3638

35 PRs went onto the alpha-ctsm5.4.CMIP7 branch
Dates span from Apr/23/2025 to Dec/4/2025 (7.5 months)
29 Tags on the branch from alpha-ctsm5.4.CMIP7.01.ctsm5.3.040 to alpha-ctsm5.4.CMIP7.21.ctsm5.3.085

For the list of PRs see:
https://github.com/ESCOMP/CTSM/pulls?page=2&q=is%3Apr+base%3Aalpha-ctsm5.4.CMIP7+is%3Aclosed

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