CESM3 Land Spinup

[wwieder]

Description:
Land spinup from CPL_HIST files for use in CESM3 contributions for CMIP7 simulations.

Let's use this issue to track everything needed for our spinup case(s)

• CLM cases from:
  • master &
  • wetlands branch (needs to be updated to master)
• CPL_HIST DATM files from CESM_dev 377 or 392 @dlawrenncar will advise:
  • 2026/9/1 CESM Proj. Meeting: Start from the end of 377.
• NDEP, aerosols and ozone from a MTt4s run, @tilmes please advise.
• glc coupler history files are set to be written @gunterl
• Do we create a CLM tag with all of the above set to come out of the box, @ekluzek @slevis-lmwg @olyson?
  • I think this would require CTSM tags 5.4.054, 5.4.055 & one more to get all the cdeps / cmeps changes set correctly?
  • 2026/9/1 I'm merging ctsm5.4.054 to the wetlands branch: Tag wetlands.n04.ctsm5.4.054.
• Get @slevis-lmwg or @wwieder added to special queue? @cecilehannay, can help?
  Sam L. and Will have been added to CESM0023.

We'll hopefully aim to start these simulations soon after the machine comes back on line.

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Case directory:
Locally:
/glade/work/$USER/$TAG/cime/scripts/$CASE

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Sandbox:
Locally:
/glade/work/$USER/$TAG

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user_nl_ changes:

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SourceMods:

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Diagnostics:
Diags (if available)

https://webext.cgd.ucar.edu/I1850/$CASE/lnd/

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Output:
Output (if still available):
/glade/scratch/$USER/archive/$CASE/

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Contacts:
@slevis-lmwg
@wwieder
@olyson

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Extra details:
Planned lengths of simulations
AD 400 yrs: X% of the land sfc not in eqm
SASU 240 yrs based on my past records, which originated from Daniel's guidance: Y% of land not in eqm
pSASU 160 yrs: Z% of the land sfc not in eqm

[wwieder]

@gunterl, can you clarify what you mean with the request that "coupler history files are set to be written"

[cecilehannay]

Get @slevis-lmwg or @wwieder added to special queue? @cecilehannay, can help?

=> @dlawrenncar can add you to the special queue. I will add you to the chat where we discuss which runs get a spot in the special queue.

[gunterl]

@wwieder - I mean to set histaux_l2x1yrg = .true. in user_nl_cpl when you set up your case.

[wwieder]

I'm moving this to a discussion, as that's that it really is. Also noting that:

• @klindsay28 will look at ENSO characteristics to identify a period from 377 that looks appropriate for us to loop over for CPL_HIST forced runs
• I'll run LDF to check for stability in DATM fields over the 169 years that have been run.