Udate to 2026.04.000 deployment

[blimlim]

1. Summary:

What has changed?

This PR updates the executable to the 2026.04.000 deployment, which fixes a CO2 conservation bug in the UM.

2. Issues Addressed:

• Update executable to 2026.04.000 #677

3. Dependencies (e.g. on payu, or model)

This change requires changes to (note pull request(s) where relevant):

• workflow manager (payu):
• model deployment (ACCESS-ESM1.6):
• model component or library dependency:
• input workflow:

4. Ad-hoc Testing

What ad-hoc testing was done? How are you convinced this change is correct (plots are good)?

See ad hoc testing results in https://github.com/ACCESS-NRI/UM7/issues/208

5. CI Testing

• !test repro has been run

6. Reproducibility

Is this reproducible with the previous commit? (If not, why not?)

• Yes
• No - !test repro commit has been run.

Changes answers in emissions driven configurations due to changes in the CO2 fluxes.

7. Performance

Has the model performance (say, throughput of model-years/wall-day) changed?

• Yes
• No
• N/A (if selected, please add a brief explanation why performance testing is not necessary for this PR)

Small change to flux calculation in UM code not expected to affect performance.

If yes, provide the numbers from your testing. Is the performance better or worse?

8. Manifests

Have you changed the executable, the input files and/or the restart files?

• Yes
• No

If yes, have you updated the manifests?

• Yes
• No

To update the manifests, run payu setup (in a cloned copy of your feature branch) with reproducibility tests turned off:

manifest:
  reproduce:
    exe: false
    input: false
    restart: false
runlog:
  enable: false

Then commit the newly created manifest files (under manifests/) only to the branch for this PR.

9. Documentation

Is the documentation updated?

• Yes
• N/A

10. Merge Strategy

• Merge commit
• Rebase and merge
• Squash

[blimlim]

!test repro commit

[github-actions]

❌ The Bitwise Reproducibility Check Failed ❌

When comparing:

• 677-update-executable-preindustrial+emissions (checksums created using commit 2259971), against
• dev-preindustrial+emissions (checksums in commit a7ad767)

🔧 The new checksums will be committed to this PR, if they differ from what is on this branch.

Further information

The experiment can be found on Gadi at /scratch/tm70/repro-ci/experiments/access-esm1.6-configs/pr678/677-update-executable-preindustrial+emissions/225997183ccb1a247832d190683c31df72f410e4, and the test results at https://github.com/ACCESS-NRI/access-esm1.6-configs/runs/71191918841.

The checksums generated by this !test command are found in the testing/checksum directory of https://github.com/ACCESS-NRI/access-esm1.6-configs/actions/runs/24376615188/artifacts/6418890056.

The checksums compared against are found here https://github.com/ACCESS-NRI/access-esm1.6-configs/tree/a7ad7679f735de3d50c5effbfd370701307c5a47/testing/checksum

Test summary:
❌ test_repro_historical
✅ test_repro_determinism

[JhanSrbinovsky]

better to include the restart in the config I suspect

[blimlim]

Thanks @JhanSrbinovsky, I'll do the restart in a separate PR to make it a bit simpler to copy this change to the other configs

[blimlim]

!cherry-pick 2259971 into dev-preindustrial+concentrations dev-4xCO2+concentrations dev-historical+concentrations dev-1pctCO2 dev-1pctCO2-rad dev-1pctCO2-bgc dev-amip dev-historical+emissions dev-flat10

[github-actions]

Automatic Git cherry-picking of commit(s) 2259971 into dev-amip failed. This usually happens when cherry-picking results in a conflic or an empty commit. To manually cherry-pick the commits and open a pull request, please follow these instructions:

1. Create new branch from target branch:

git checkout dev-amip
git pull
git checkout -b cherry_pick_from_pr678_into_dev-amip

2. Cherry-pick commits:

git cherry-pick 225997183ccb1a247832d190683c31df72f410e4

3. Fix any conflicts and/or empty commits by following the instructions provided by Git.
4. Push the new branch:

git push --set-upstream origin cherry_pick_from_pr678_into_dev-amip

5. Open a new pull request on github making sure the target branch is set to dev-amip.

[github-actions]

Automatic Git cherry-picking of commit(s) 2259971 into dev-historical+concentrations was successful.

The new pull request can be reviewed and approved here.

[github-actions]

Automatic Git cherry-picking of commit(s) 2259971 into dev-4xCO2+concentrations was successful.

The new pull request can be reviewed and approved here.

[github-actions]

Automatic Git cherry-picking of commit(s) 2259971 into dev-flat10 was successful.

The new pull request can be reviewed and approved here.

[github-actions]

Automatic Git cherry-picking of commit(s) 2259971 into dev-1pctCO2-bgc was successful.

The new pull request can be reviewed and approved here.

[github-actions]

Automatic Git cherry-picking of commit(s) 2259971 into dev-historical+emissions was successful.

The new pull request can be reviewed and approved here.

[github-actions]

Automatic Git cherry-picking of commit(s) 2259971 into dev-1pctCO2 was successful.

The new pull request can be reviewed and approved here.

[github-actions]

Automatic Git cherry-picking of commit(s) 2259971 into dev-1pctCO2-rad was successful.

The new pull request can be reviewed and approved here.

[github-actions]

Automatic Git cherry-picking of commit(s) 2259971 into dev-preindustrial+concentrations was successful.

The new pull request can be reviewed and approved here.