2026 Software Engineering meeting notes

July 6, 2026

• Machine status and meeting notices (5 min)
• Upcoming Meetings (5 min)
• PR board status (10 min)
• Latest issues (5 min)
• FATES-CTSM6 Code freeze status (5 min)
• Calibration progress update

Wins 🎉

Machine status and notices 🖥️

• CISL: Tuesday July 14, derecho
• NERSC: July 22-Aug 03, perlmutter

Upcoming meetings and events 🗓️

• Transatlantic FATES meeting: Tuesday July 14
  • Action: Greg to send Rosie a reminder email
• FATES modeling meeting: July 16

PR board status update

Integrated

• Fixed Prescribed P Uptake (#1587)
• Hydro Stability (#851)

New

• Allocate Space to LU disturbance restart array

Latest issues and discussions of note

• normalized profiles and TRS

FATES-CLM6 code freeze status

• Historical transient project board

Walk-on topics

June 29, 2026

• NorESM Updates (Matvey)
• FATES-CTSM6 Code freeze status (5 min)

NorESM updates

• H2O balance error issue discussion
  • Charlie: conceptually there is a some survivorship of old cohorts during landuse patch transitions

FATES-CLM6 code freeze status

• Reference: maintenance branch document
• Historical transient project board
• Proposal (Ryan): We need to start bringing in non-B4B PRs into FATES.
  • Should we:
    • A: Tag FATES at 2.0.0 now (and create maintenance branch)
    • B: Start the maintenance branch even though we're not at 2.0.0 yet
    • C: Create dev branch and merge non-B4B into dev branch (to be reconciled later)
  • Consensus: Go with B
    • Creating maintenance at 2.0.0 is ideal, but given uncertainty in 2.0 timeframe, better to start maintenance branch now
    • Option C would require rebasing the dev branch onto main eventually and re-validating test results (complex)

June 22, 2026

• Wins (1 min)
• Machine status and meeting notices (5 min)
• Upcoming Meetings (5 min)
• PR board status (10 min)
• Latest issues (5 min)
• FATES-CTSM6 Code freeze status (5 min)
• Calibration progress update

Wins 🎉

• Jennifer is now the ELM lead
• Charlie got the CESM distinguished contributor guide

Machine status and notices 🖥️

• CISL: Tuesday July 14, derecho
• NERSC: July 22-Aug 03, perlmutter

Upcoming meetings and events 🗓️

• Transatlantic FATES meeting: Tuesday June 23
  • Action: Greg to send Rosie a reminder email
• FATES modeling meeting: July 2, TBD
  • Charlie will be out
  • Action: Charlie to cancel

PR board status update

Integrated

• Deactivate history fields in SP mode (#1568)
• Remove variables to exclude for fates_sp user mod (ctsm#4079)

Ready to Integrate

• FATES API 46 E3SM#8325

New

• Patch fusion crash in historic land only simulation fix (#1579): cherry-picked from NorESM/fates
• Interstitial bareground (#1577)
  • Related: column weighting discussion
    • https://github.com/ESCOMP/CTSM/discussions/4096
    • Bill noted this is fundamentally incompatible with a gross transitions scheme, but rewrite might be easy
  • How do we handle canopy air turbulance physics? Roughness length and zstar.
    • How do we address these parameters from a complex FATES canopy?
    • Testing
      • Comparisons against eddy covariance sites in ST3 mode
        • Adrianna started a similar project with NEON sites: will email notes
      • Adrianna: functional unit testing
      • Global no comp runs
  • Charlie: Does SNICAR work on the bareground patches only?

Latest issues and discussions of note

• Variables in both bc_in and sites: Confusing and error-prone (#1576)
• Running FATES with soil thickness (#1574)

FATES-CLM6 code freeze status

• Reference: maintenance branch document
• Historical transient project board

Walk-on topics

• CSEG LLM discussion emails
• Adrianna: New CGD ASP postdoc in paleogroup. Wants to use FATES for paleogroup.

June 15, 2026

Canceled due to CESM workshop and other conflicts

---

June 8, 2026

• Wins (1 min)
• Machine status and meeting notices (5 min)
• Upcoming Meetings (5 min)
• PR board status (10 min)
• Latest issues (5 min)
• FATES-CTSM6 Code freeze status (5 min)
• Calibration progress update

Wins 🎉

• Lots of new bugs being found to be squashed!

Machine status and notices 🖥️

• CISL: None planned
• NERSC: Wednesday June 17, perlmutter

Upcoming meetings and events 🗓️

• Transatlantic FATES meeting: Tuesday June 16
  • Conflicts with CESM workshop
    • Greg: Ask Charlie to move this to Tuesday June 22
    • Ryan: FATES-lite meeting the day before? Consensus is yes.
  • Rosie: Skip July due to holidays
• CESM 2026 Workshop: June 15 - 17
• FATES modeling meeting: June 18, TBD
  • Cancel: Ryan traveling and conflict

PR board status update

New

• bug fix - termination for grazed cohorts (#1573)

Integrated

• Initialize prescribed fire site-level variables (#1567)

Hold

• Deactivate history fields in SP mode (#1568)

In progress

• FATES API 46 E3SM#8325
• #1573: needs updating to cherry-pick

Latest issues and discussions of note

• NorESM CTSM issues:
  • Issues seem to be due to things that are on the verge of dying
  • Historic land only simulation crashed with water balance error (#218)
    • FATES tracking issue: Grazing and zero organ allocations (fix), what to do (#1575)
      • Rosie: Testing NorESM/ctsm#62 (with #61): DIFFs are small, adjusted grazing numbers
        • Originally made it so that grazers could eat broad leaf evergreen trees. Reduce palatabilty of tropical broadleaf evergreen to very low number (or zero)?
        • NorESM team wants to move forward with addressing this even though it would require recalibration
        • Marcos: insect herbivory already accounted for in leaf turnover rates?
          • Aside: palabilty is a strong function on nitrogen content
  • More h2o balance errors in historic land only (#229)
    • Rosie: Absence of conticular conductance?
  • Mass balance error - FATES land only simulation (#232)
  • Testing support ideas
    • See Jessie's spreadsheet emailed out for list of issues
    • Use Jessie's restart files and runs directly into the crash. Will this work if running on a different machine?
      • Or do a landuse PPE
        • Rosie to send Adrianna the reconstructed fates land use data files
  • Jennifer: note we might need to model "zombie trees" for wildfire runs for the future
    • JEDI shows real trees, but the question is do we add them to the model
• Variables in both bc_in and sites: Confusing and error-prone (#1576)
• Running FATES with soil thickness (#1574)

FATES-CLM6 code freeze status

• Reference: maintenance branch document

Calibration progress update

Walk-on topics

---

June 1, 2026

• Wins (1 min)
• Machine status and meeting notices (5 min)
• Upcoming Meetings (5 min)
• PR board status (10 min)
• Latest issues (5 min)
• FATES-CTSM6 Code freeze status (5 min)
• Calibration progress update

Wins 🎉

Machine status and notices 🖥️

• CISL:
• NERSC: Wednesday June 17, perlmutter

Upcoming meetings and events 🗓️

• FATES modeling meeting: June 4, TBD

PR board status update

New

Integrated

• Update FATES tag to API 44 (E3SM-Project/E3SM#8278)

Ready to Integrate

Testing

Latest issues and discussions of note

FATES-CLM6 code freeze status

• Reference: maintenance branch document

Calibration progress update

Walk-on topics

---

May 25, 2026

Memorial Day Holiday

May 18, 2026

FATES transatlantic meeting week

---

May 11, 2026

• Wins (1 min)
• Machine status and meeting notices (5 min)
• Upcoming Meetings (5 min)
• PR board status (10 min)
• Latest issues (5 min)
• FATES-CTSM6 Code freeze status (5 min)
• Calibration progress update

Wins 🎉

Machine status and notices 🖥️

• CISL: May 12-13, derecho and casper
• NERSC: Wednesday May 20, perlmutter

Upcoming meetings and events 🗓️

• FATES modeling meeting: May 21, Maoya Bassiouni
• Transatlantic coordination meeting setup: First meeting Tuesday May 19

PR board status update

New

• 1565 - update the petiole length
• 1567 - Initialize prescribed fire site-level variables

Integrated

• Split initial density into to parameters with a switch on HLM side (#1550)

Ready to Integrate

• Update FATES tag to API 44 (E3SM-Project/E3SM#8278): Was held up by integration machine mainenance. This should start integration today.

Testing

• add new fates namelist switch for dbh init when nocomp is on (ctsm#3910): final testing

Updates

• Enable DBH initialization to "full FATES" on coldstarts (#1558): Consensus is that we will bring this in after 2.0
• Update CLMBuildNamelist to allow AD spinup with FATES (not SP) (#3962): Adrianna to email NorESM team about setup issues
  • Ryan: This would be a good topic for the first transatlantic meeting

Latest issues and discussions of note

• How does SPITFIRE mode 3 (prescribed successful ignition) work when the model is run on irregular grids? (#1562)
• Crops and land use and SP mode (#1563): defer conversation until the transatlantic meeting
• Link to NorESM-FATES historical run crash (NorESSM/CTSM issue 218) (#1564)
• prescribed n uptake rate used for prescribed p (bug) (#1566)

FATES-CLM6 code freeze status

• Reference: maintenance branch document

Calibration progress update

Walk-on topics

---

May 4, 2026

• Wins (1 min)
• Machine status and meeting notices (5 min)
• Upcoming Meetings (5 min)
• PR board status (10 min)
• Latest issues (5 min)
• FATES-CTSM6 Code freeze status (5 min)
• Calibration progress update

Wins 🎉

• Greg figured out the ERS issue for the Multi-column MVP
• Ryan making good progress on nutrients model updates

Machine status and notices 🖥️

• CISL: May 12-13, derecho
• NERSC: Wednesday May 20, perlmutter

Upcoming meetings and events 🗓️

• FATES modeling meeting: May 7, Junyan Ding
• Transatlantic coordination meeting setup
  • Remember to fill out the Rally form sent via email
  • Looks like Tuesdays at 10AM ET / 7AM PT

PR board status update

Integrated

• Complete the FATES-CLM nitrogen coupling (ESCOMP/ctsm#3409)

Ready to Integrate

• Update FATES tag to API 44 (E3SM-Project/E3SM#8278)
• ctsm5.4.037: mirror: ctsm5.4.002_noresm_v6: fix for (fates) year-boundary restart issue (ESCOMP/ctsm#3940)

Updates

• Split initial density into to parameters with a switch on HLM side (#1550): Reviewed. Matvey to revert update to seed init parameter setting.
  • add new fates namelist switch for dbh init when nocomp is on (ctsm#3910): Reviewed. Matvey to add test for new option that updates seed init on the fly.
• improve hydro stability (#851): Ryan working on bringing this up-to-date and addressing issue that stalled this.

Latest issues and discussions of note

• no new issues

FATES-CLM6 code freeze status

• Reference: maintenance branch document

Calibration progress update

• Rosie: Issues with historical runs
  • Jessie's run should be done tomorrow.
  • Matvey reconciling ctsm5.4.034: https://github.com/NorESMhub/CTSM/pull/212
    • We should get an updated fates parameter file after this

Walk-on topics

• Jennifer: report back from E3SM leadership meeting, v4/v5 planning
  • Seasonal-to-decadal
  • Water and energy, extremes, biology
• Rosie: ECHOSAT product bookmark issue

---

April 27, 2026

• Wins (1 min)
• Machine status and meeting notices (5 min)
• Upcoming Meetings (5 min)
• PR board status (10 min)
• Latest issues (5 min)
• FATES-CTSM6 Code freeze status (5 min)
• Calibration progress update

Wins 🎉

• Jing's A2MC agent found it's first bug in the code.
  • Ryan to create and issue and PR for this

Machine status and notices 🖥️

• CISL: May 12-13, derecho
• NERSC: Wednesday May 20, perlmutter

Upcoming meetings and events 🗓️

• FATES modeling meeting: May 7, Junyan Ding
• Transatlantic coordination meeting setup
  • Ryan to use rally or timeful.app

PR board status update

Integrated

• ctsm5.4.034: bug fix to the FATES land use driver input code (ESCOMP/ctsm#3902), new LUPF variables (cherry-picked mirror of NorESMhub) (#1548), Update Grazing Logic (cherry-picked mirror of NorESMHub 55) (#1547), Complete the FATES-CLM nitrogen coupling (#1472)

Testing

• Update FATES tag to API 44 (E3SM-Project/E3SM#8278): Greg waiting for final e3sm land developer test to complete. Should be integrated this week.
• Complete the FATES-CLM nitrogen coupling (ESCOMP/ctsm#3409): Sam L addressing some review comments prior to testing

Under Review

• Split initial density into to parameters with a switch on HLM side (#1550): Greg to review this week. Last planned PR before maintenance branch creation.
  • add new fates namelist switch for dbh init when nocomp is on (ctsm#3910)

Updates

New

• FATES API 45 (Nutrient NL switch updates) (#8325): Ryan drafted to bring align with #1472 updates
• Boundary condition refactor - multi-column FATES MVP (glemieux/#36): building on top of #1477
  • This will be turned into its on PR on NGEET repo once #1477 is merged.

Latest issues and discussions of note

• Cold-starting full-FATES, options (#1559)
• Adding a subdirectory to tools for supporting workflow pipelines (#1560)

FATES-CLM6 code freeze status

• maintenance branch document

Calibration progress update

• no updates

---

April 20, 2026

• Wins (1 min)
• Machine status and meeting notices (5 min)
• Upcoming Meetings (5 min)
• PR board status (10 min)
• Latest issues (5 min)
• FATES-CTSM6 Code freeze status (5 min)
• Calibration progress update

Wins 🎉

• Sam R: Presentation to NOAA about agentic coding

Machine status and notices 🖥️

• CISL: Tuesday May 05, derecho
  • Sam R: this is moving to May 12-13
• NERSC: Wednesday May 20, perlmutter

Upcoming meetings and events 🗓️

• FATES modeling meeting
  • April 23: Cancelled
  • May 7: Junyan Ding, COMPASS FATES-hydro work
• Transatlantic coordination meeting setup
  • Purpose: discuss future plans for FATES API changes. Coordination focus (e.g. avoid cherry-picking)
  • Poll feedback
    • Sam: Would be ideal to have date x time matrix selection. Note NCAR can't use when2meet due to malware in ads

PR board status update

Integrated

• Update LUH missing value checks (#1555), ctsm5.4.033: Update FATES tag with fix for LUH no_nan data set issue (ESCOMP/ctsm#3926)

Testing

• ctsm5.4.034: bug fix to the FATES land use driver input code (ESCOMP/ctsm#3902)
• new LUPF variables (cherry-picked mirror of NorESMhub) (#1548): Charlie made suggestions noting duplicates

Under Review

• Complete the FATES-CLM nitrogen coupling (#1472)
  • Complete the FATES-CLM nitrogen coupling (ESCOMP/ctsm#3409)
  • Greg: Move this to testing or more review? Note that Sam Levis has been running build/run tests
    • Sam R to add review
    • Will: should this have testing beyond the regression testing?
      • Discuss this within context of queue at CTSM SE meeting on Thursday as well as how to conduct future answer changing tests for ctsm-fates in the future.

Updates

• Update FATES tag to API 44 (E3SM-Project/E3SM#8278): added landuse transition option (#1489), land use no nan data sets (#1555), fates restart issue fix (ctsm#3940)
  • Merge fixed order of LUxPFT matrix read (#E3SM-Project/E3SM#8259) into #8278 if above is B4B during testing
• Split initial density into to parameters with a switch on HLM side (#1550): CTSM SE focused discussion last week has majority in support of brining this in

New

• Enable DBH initialization to "full FATES" on coldstarts (#1558)

Latest issues and discussions of note

• Cold-starting full-FATES, options (#1559): Discussion shows interest in enabling this capability. Discuss with absent members next week as well.

Calibration progress update

• deferred

---

April 13, 2026

• Wins (1 min)
• Machine status and meeting notices (5 min)
• Upcoming Meetings (5 min)
• PR board status (10 min)
• Latest issues (5 min)
• Poll results
• FATES-CLM6 Code freeze status (5 min)
• Calibration progress update

Machine status and notices 🖥️

• CISL: none
• NERSC: Wednesday April 15, perlmutter

Upcoming meetings and events 🗓️

• FATES modeling meeting: April 23, TBD

PR board status update

Integrated

• Update aboveground biomass allometry parameters for extratropical trees (#1522)

New

• Update LUH missing value checks (#1555): B4B results against pre-intel compiler update
  • Charlie: recommend keeping the old logic as well to provide backwards compat with folks who might be using the NaN _FillValue land use data sets
    • Ryan: Note that isnan doesn't always work; Recommending checking that the value matches itself.
  • Ryan: Historically we don't do logic tests against floats.
  • ctsm5.4.033: Update FATES tag with fix for LUH no_nan data set issue (ESCOMP/ctsm#3926)
  • Update FATES tag to API 44 (E3SM-Project/E3SM#8278)
• fixed order of LUxPFT matrix read (#E3SM-Project/E3SM#8259)

Under Review

• Update Grazing Logic (cherry-picked mirror of NorESMHub 55) (#1547): Question to Rosie on status of last comment
  • Is the NorESM team not implementing the recent commits?
    • If so, should the main fates branch mirror that fact (i.e. should we revert those updates)?
      • Charlie is ok with going whichever way that Rosie wants to go.
      • Action: change paranthesis to match previous logic
• new LUPF variables (cherry-picked mirror of NorESMhub) (#1548): Charlie made suggestions noting duplicates
  • Ryan to review

Updates

• Split initial density into to parameters with a switch on HLM side (#1550)
  • add new fates namelist switch for dbh init when nocomp is on (ctsm#3910)
  • Ryan to work up alternate version of this
• Complete the FATES-CLM nitrogen coupling (#1472): bring this in for fates-maintenance?
  • Rosie: the sooner this comes into NorESM, the better.

Latest issues and discussions of note

• error in land use driver data in land use x PFT data (#1551)
• LUH NaN issues (see above new PRs): #1552 with children #1553, #1554
• FYI: not reproducible at year boundary (NorESMhub/NorESM#790): coupled restart issue

FATES 2.0 poll results

• Full support for update sci tag to 2.0.0

FATES-CLM6 code freeze status

• maintenance branch document

Calibration progress update

• no updates

Walk-on topics

• Rosie: Bringing MIMICS plus to FATES

---

April 06, 2026

• Wins (1 min)
• Machine status and meeting notices (5 min)
• Upcoming Meetings (5 min)
• PR board status (10 min)
• Latest issues (5 min)
• FATES-CLM6 Code freeze status (5 min)
• Calibration progress update

Machine status and notices 🖥️

• CISL: Tuesday April 7, derecho
• NERSC: Wednesday April 15, perlmutter

Upcoming meetings and events 🗓️

• FATES modeling meeting: April 9, Zachary Robbins
• Improving Scientific Software conference: April 6-9
  • CTSM SE meeting impacted

PR board status update

Integrated

• Updates to land use clearing logic (#1489)
  • ctsm5.4.030: Add a FATES namelist option for land use transition logic (ctsm#3728): minor build update and re-test

New

• Add guidance on the use of AI contributions (#1549)
• Split initial density into to parameters with a switch on HLM side (#1550)
  • add new fates namelist switch for dbh init when nocomp is on (ctsm#3910)

Under Review

• Update Grazing Logic (cherry-picked mirror of NorESMHub 55) (#1547)
• new LUPF variables (cherry-picked mirror of NorESMhub) (#1548)

Latest issues and discussions of note

• No new issues or discussions

FATES-CLM6 code freeze status

Calibration progress update

---

March 9, 2026

• Machine status and meeting notices (5 min)
• Upcoming Meetings (5 min)
• Latest issues (5 min)
• Calibration progress update

Machine status and notices 🖥️

• CISL: March 3rd, ALL HPC resources Maintenance
• NERSC: 18-19 March, Perlmutter Maintenance

Upcoming meetings and events 🗓️

• FATES modeling meeting: March 12: Performance Improvements (Ryan)

---

March 2, 2026

• Machine status and meeting notices (5 min)
• Upcoming Meetings (5 min)
• PR board status (10 min)
• Latest issues (5 min)
• Debrief from LMWG Meeting
• Calibration progress update
• FATES-CLM6 Code freeze status (5 min)
• Speed Refactor Updates

Machine status and notices 🖥️

• CISL: March 3rd, ALL HPC resources Maintenance
• NERSC: 18-19 March, Perlmutter Maintenance

Upcoming meetings and events 🗓️

• FATES modeling meeting: March 12: TBD

PR board status update

New

• NorESM Mirror - vcmax age fix

Integrated

• Frozen Hydro Mort Fix (#1533)
• E3SM JSON API (7954)
• Adding some more land-use-change and globally-relevant history variables (#1485)

Testing

• Damage Loop Escape (1532)
• LU Super PR
• Nitrogen Coupling (#1472): Reproducing ERS restart failure.

Updates/Reviewing

• Refactor boundary condition interface structure (#1477)

Discussing

• on hold: direct usage of parameter datastructure - allometry proof of concept

Latest issues and discussions of note

• NorESM Restart Error - COMPLETE

FATES-CLM6 code freeze status

Calibration progress update

---

February 23, 2026

• Machine status and meeting notices (5 min)
• Upcoming Meetings (5 min)
• PR board status (10 min)
• Latest issues (5 min)
• Speed Refactor Overview
• Calibration progress update
• FATES-CLM6 Code freeze status (5 min)

Machine status and notices 🖥️

• CISL: March 3rd, ALL HPC resources Maintenance
• NERSC: 18-19 March, Perlmutter Maintenance

Upcoming meetings and events 🗓️

• FATES modeling meeting: 26 February: TBD
• CLM Land Model Working Group meeting: 24-26 February

PR board status update

Integrated

• Testing Framework (#1519)
• E3SM Zenith Angle Updates

Testing

• NEXT: frozen soil mortality
• Adding some more land-use-change and globally-relevant history variables (#1485) - Need Sam R approval
• JSON formatted FATES parameters: ready for review, tested on pm-cpu
  • Get this into the integration queue ASAP so we can see how regression tests work out across other machines
  • Needs rebasing against master after #7899 integrated

Updates/Reviewing

• Add some biophysical variables (#1407)
• Refactor boundary condition interface structure (#1477)
• Damage Loop Escape (1532)

Discussing

• on hold: direct usage of parameter datastructure - allometry proof of concept

New -add area and biomass history variables indexed by landuse x pft #1535

Latest issues and discussions of note

• NorESM Restart Error
• NorESM Two-Stream Error
• TRS fails with overflow

FATES-CLM6 code freeze status

Calibration progress update

---

February 09, 2026

• Machine status and meeting notices (5 min)
• Upcoming Meetings (5 min)
• PR board status (10 min)
  • NorESM-side fix for 1492
• Latest issues (5 min)
• FATES-CLM6 Code freeze status (5 min)
• Calibration progress update

Machine status and notices 🖥️

• CISL: Nothing scheduled?
• NERSC: 18-20 February, Perlmutter

Upcoming meetings and events 🗓️

• FATES modeling meeting: 12 February: TBD (likely office hours)
• CLM Land Model Working Group meeting: 24-26 February

PR board status update

Integrated

• Testing Framework (#1519)
• E3SM Zenith Angle Updates

Testing

• Adding some more land-use-change and globally-relevant history variables (#1485) - Need Sam R approval
• JSON formatted FATES parameters: ready for review, tested on pm-cpu
  • Get this into the integration queue ASAP so we can see how regression tests work out across other machines
  • Needs rebasing against master after #7899 integrated
• Refactor boundary condition interface structure (#1477): ready for review, tests are (near) B4B

Updates/Reviewing

• Add some biophysical variables (#1407)

Discussing

• direct usage of parameter datastructure - allometry proof of concept

New

• Damage Loop Escape (1532)

Latest issues and discussions of note

• trimming initialization

FATES-CLM6 code freeze status

Calibration progress update

---

February 02, 2026

• Wins (1 min)
• Machine status and meeting notices (5 min)
• Upcoming Meetings (5 min)
• PR board status (10 min)
• Latest issues (5 min)
• FATES-CLM6 Code freeze status (5 min)
• Outputs for CMOR and simulations
• Calibration progress update

Machine status and notices 🖥️

• CISL: 03 February, derecho
• NERSC: 18-20 February, perlmutter

Upcoming meetings and events 🗓️

• FATES modeling meeting: 12 February: TBD (likely office hours)
• CLM Land Model Working Group meeting: 24-26 February

PR board status update

Integrated

• Updates to FATES zenith angles on the first step of non-continue restarts (E3SM#7899): waiting to be integrated

Testing

• Testing Framework Update (#1519): Greg to finish this
  • Adrianna to update the code to convert CDL to NetCDF.
    • Greg to check in end of day. It's ok to just move forward with uploading the netcdf file.

Updates

• JSON formatted FATES parameters: ready for review, tested on pm-cpu
  • Get this into the integration queue ASAP so we can see how regression tests work out across other machines
  • Needs rebasing against master after #7899 integrated
• Refactor boundary condition interface structure (#1477): ready for review, tests are (near) B4B

New

• direct usage of parameter datastructure - allometry proof of concept
• Add a FATES namelist option for land use transition logic #3728
  • Coupled with Updates to land use clearing logic (#1489)
    • Keep the parameter file update, Jessie to update to JSON format, provide B4B values for new param in comments of the PR

Latest issues and discussions of note

• CLM-FATES results in odd global forest patterns when hydro is on (#1527)
  • Marcos meeting with Steven on Thursday to discuss this more
  • Charlie: Soil texture or temperature initial condition wrt. Simple check, initialize soils to saturated and check.
  • Marcos: Difference in pedotransfer between ELM and CLM?
  • Will: Maybe surface dataset differences?

FATES-CLM6 code freeze status

• relevant discussion below

Outputs for CMOR and simulations (Rosie)

• NorESM CTSM issue #188
  • Rosie: Is CTSM going through this?
    • Will: Yes, bringing in Sam Levis who has been working on this
  • Charlie to reply in thread to remaining issues we didn't get to today

Calibration progress update

• Lack of very big trees in the boreal region email thread (Adrianna, Rosie, Jessica)
  • AGB allometry parameters seem to have the greatest impact on creating large trees (reducing too many little trees)
    • GPP increased faster (wider DBH -> more leaves)

---

January 26, 2026

• Wins (1 min)
• Machine status and meeting notices (5 min)
• Upcoming Meetings (5 min)
• PR board status (10 min)
• Latest issues (5 min)
• FATES-CLM6 Code freeze status (1 min)
• Calibration progress update

Machine status and notices 🖥️

• CISL: 03 February, derecho
• NERSC: Jan 26, 13:00–14:00, perlmutter DTNs

Upcoming meetings and events 🗓️

• FATES modeling meeting:
• CLM Land Model Working Group meeting: 24-26 February
  • Will: Request for presentations open until the 06 February. Note this year is a CuPID tutorial.
    • Will asked Rosie to give a talk about NorESM. Adrianna will give a talk. Would be good to get FATES overview talk like previous years.
    • Adrianna: We should hold a hackathon to get FATES output variables into CuPID

PR board status update

Integrated

• changes for NorESM nocomp simulation efforts #1510 Testing
• Updates to FATES zenith angles on the first step of non-continue restarts (E3SM#7899)

Latest issues and discussions of note

FATES-CLM6 code freeze status

• Will: Matvey has a number of PRs that address bugfixes

Calibration progress update

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January 19, 2026

Canceled due to federal holiday

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January 12, 2026

• Wins (1 min)
• Machine status and meeting notices (5 min)
• Upcoming Meetings (5 min)
• PR board status (10 min)
• Latest issues (5 min)
• FATES-CLM6 Code freeze status (1 min)
• Calibration progress update

Machine status and notices 🖥️

• CISL: 03 February, derecho
• NERSC: 21-23 January, perlmutter

Upcoming meetings and events 🗓️

• FATES modeling meeting: 15 January: Office hours
• CLM Land Model Working Group meeting: 24-26 February
  • Will: Request for presentations open until the 06 February. Note this year is a CuPID tutorial.
    • Will asked Rosie to give a talk about NorESM. Adrianna will give a talk. Would be good to get FATES overview talk like previous years.
    • Adrianna: We should hold a hackathon to get FATES output variables into CuPID

PR board status update

Integrated

• Unit Fix to Smoothed NPP used for free living fixation

Testing

• changes for NorESM nocomp simulation efforts #1510: Waiting on computing account top up
• Updates to FATES zenith angles on the first step of non-continue restarts (E3SM#7899): Reviewing unexpected DIFFs
  • Greg and Ryan think they've ID'd a fix.

Latest issues and discussions of note

• Site level simulation time zone (#1521)

FATES-CLM6 code freeze status

• Will: Matvey has a number of PRs that address bugfixes

Calibration progress update

• no updates

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January 5, 2026

• Wins (1 min)
• Machine status and meeting notices (5 min)
• Upcoming Meetings (5 min)
• PR board status (10 min)
• Latest issues (5 min)
• FATES-CLM6 Code freeze status (1 min)

Wins and Whimsy 🎉

• Greg: nutrients test in BC refactor now B4B

Machine status and notices 🖥️

• CISL: none
• NERSC: 21-23 January, perlmutter

Upcoming meetings and events 🗓️

• FATES modeling meeting: 15 January: TBD
• NGEE-Arctic All-Hands: 12-13 January

PR board status update

Integrated

• JSON based parameters (#1493), FATES JSON parameter files (ctsm#3570)

Review

• changes for NorESM nocomp simulation efforts #1510
  • Ryan: Ryan is creating a patch file for holding the nocomp negative init density runs. Rosie can use this to update with the nocomp calibration values.

Needs Reviews

• Unit Fix to Smoothed NPP used for free living fixation: Greg to review toda

Updates

• Nitrogen Coupling (#1472): Ryan and Sam continued to meet
• Updates to FATES zenith angles on the first step of non-continue restarts (E3SM#7899): Greg to test

New

• Testing Framework Update (#1519)
  • Walkthrough
    • New script: generate_empty_test sets up boilerplate stuff for new test development
      • See templates directory
    • Same top line scripts for running tests
    • Improved readme with test build walkthrough example
    • Put tests in the config file when creating new ones
    • Tests actually live in testing/tests/<test_type>
    • framework is where the python testing infrastructure lives
      • Expanded classes for different test types
      • builder is responsible for compiling everything

Latest issues and discussions of note

• Create release github branch (#1520): task issue for the FATES-CLM6 freeze (see below)

FATES-CLM6 code freeze status

• Greg: Release tag deadline for ctsm still in flux
  • #1510 is likely the last stuff that will need to come in to make a release
    • NorESM freeze is imminent

Calibration progress update

• Discussion of boreal forest LAI issue
  • MODIS LAI is much lower than fates
  • Charlie: do we need to improve the canopy snow interception model (to adjust LAI due to snow occlusion)
  • Ryan: two-stream model does account for snow occlusion, but are we passing this information to the HLM?
• Adrianna: working on c4 grass calibration

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