ctsm5.4.037

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Tag name: ctsm5.4.037
Originator(s): Ryan Knox, Matvey Debolskiy
Date: Mon May 4 04:51:35 PM MDT 2026
One-line Summary: Fix for FATES year-boundary restart issue

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

Move clm-2-fates time passing in the fates restart routine to flag='read' condition

Significant changes to scientifically-supported configurations
--------------------------------------------------------------
[Remove entire section if none of the boxes are checked.]

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.]

[ ] clm6_0

[ ] clm5_0

[ ] ctsm5_0-nwp

[ ] clm4_5

[X] fates


Bugs fixed
----------

List of CTSM issues fixed (include CTSM Issue # and description):

List of other issues fixed:
- [NorESMhub/NorESM Issue #790: not reproducible at year boundary](https://github.com/NorESMhub/NorESM/issues/790)


Testing summary:
----------------

[PASS means all tests PASS; OK means tests PASS other than expected fails.]

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

derecho ----- OK
izumi ------- OK

fates tests: (give name of baseline if different from CTSM tagname, normally fates baselines are fates-<FATES TAG>-<CTSM TAG>)
derecho ----- OK
izumi ------- OK


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

Changes answers relative to baseline: Yes

Summarize any changes to answers, i.e.,
- what code configurations: FATES with restarts written
- what platforms/compilers: all
- nature of change (roundoff; larger than roundoff/same climate; new climate):

If bitwise differences were observed, how did you show they were no worse
than roundoff? Roundoff differences means one or more lines of code change results
only by roundoff level (because order of operation changes for example). Roundoff
changes to state fields usually grow to greater than roundoff as the simulation progresses.

Other details
-------------

Pull Requests that document the changes (include PR ids):
- [ESCOMP/CTSM Pull Request #3940: ctsm5.4.037: mirror: ctsm5.4.002_noresm_v6: fix for (fates) year-boundary restart issue by rgknox](https://github.com/ESCOMP/CTSM/pull/3940)

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