[Douglas Clark (doucla)]

PR Summary

Sci/Tech Reviewer: Maggie (@maggiehendry)
Code Reviewer:

Updating arguments in jule_extra_kernel to maintain consistency with recent developments in JULES.

Closes issue #858
Linked PRs MetOffice/UM#121 and MetOffice/jules#143

Note that this change includes two PARAMETERs (i.e. hardwired values) in jules_extra_kernel_mod.F90 (global_land_pts = 1 and l_is_master_task = .FALSE.). These are required so that minimal space is allocated for the new variables associated with the minor reservoirs. The minor reservoir functionality is not currently available in LFRic.

Code Quality Checklist

• I have performed a self-review of my own code
• My code follows the project's style guidelines
• Comments have been included that aid understanding and enhance the readability of the code
• My changes generate no new warnings
• [] All automated checks in the CI pipeline have completed successfully

Testing

• I have tested this change locally, using the LFRic Apps rose-stem suite
• If any tests fail (rose-stem or CI) the reason is understood and acceptable (e.g. kgo changes)
• I have added tests to cover new functionality as appropriate (e.g. system tests, unit tests, etc.)
• Any new tests have been assigned an appropriate amount of compute resource and have been allocated to an appropriate testing group (i.e. the developer tests are for jobs which use a small amount of compute resource and complete in a matter of minutes)

trac.log

The following tested branch differs from the PR branch in a couple of ways:

1. It was necessary to upgrade to a newer revision to include Rose stem bug fixes unrelated to PR.
2. The second trac.log was added as I forgot to upgrade coupled_rivers so lfric_atm_coupled_ex1a_developer was run. Upgrade coupled_rivers app using compatible JULES macro #827 is open to upgrade this app manually once changes to the JULES upgrade macro cease being committed.

Test Suite Results - lfric_apps - lfric_apps-maggiehendry_minor_reservoirs/run1

Suite Information

Item	Value
Suite Name	lfric_apps-maggiehendry_minor_reservoirs/run1
Suite User	margaret.hendry
Workflow Start	2026-10-22T16:15:08
Groups Run	developer

Dependency	Reference	Main Like
casim	MetOffice/casim@996db30	True
jules	KatieBlackford/jules@vn8.2_minor_reservoirs	True
lfric_apps	maggiehendry/lfric_apps@maggiehendry_minor_reservoirs	False
lfric_core	MetOffice/lfric_core@0258fdb	True
moci	MetOffice/moci@2026.07.1	True
SimSys_Scripts	MetOffice/SimSys_Scripts@77a5166	True
socrates	MetOffice/socrates@2026.07.1	True
socrates-spectral	MetOffice/socrates-spectral@2026.07.1	True
ukca	MetOffice/ukca@c372b36	True

Task Information

✅ succeeded tasks - 1253

Test Suite Results - lfric_apps - lfric_apps-maggiehendry_minor_reservoirs/run2

Suite Information

Item	Value
Suite Name	lfric_apps-maggiehendry_minor_reservoirs/run2
Suite User	margaret.hendry
Workflow Start	2026-10-22T16:57:02
Groups Run	lfric_atm_coupled_ex1a_developer

Dependency	Reference	Main Like
casim	MetOffice/casim@996db30	True
jules	KatieBlackford/jules@vn8.2_minor_reservoirs	True
lfric_apps	maggiehendry/lfric_apps@maggiehendry_minor_reservoirs	False
lfric_core	MetOffice/lfric_core@0258fdb	True
moci	MetOffice/moci@2026.07.1	True
SimSys_Scripts	MetOffice/SimSys_Scripts@77a5166	True
socrates	MetOffice/socrates@2026.07.1	True
socrates-spectral	MetOffice/socrates-spectral@2026.07.1	True
ukca	MetOffice/ukca@c372b36	True

Task Information

✅ succeeded tasks - 24

Security Considerations

• I have reviewed my changes for potential security issues
• [] Sensitive data is properly handled (if applicable) - not applicable
• [] Authentication and authorisation are properly implemented (if applicable) - not applicable

Performance Impact

• Performance of the code has been considered and, if applicable, suitable performance measurements have been conducted

AI Assistance and Attribution

• Some of the content of this change has been produced with the assistance of Generative AI tool name (e.g., Met Office Github Copilot Enterprise, Github Copilot Personal, ChatGPT GPT-4, etc) and I have followed the Simulation Systems AI policy (including attribution labels)

Documentation

• Where appropriate I have updated documentation related to this change and confirmed that it builds correctly

PSyclone Approval

• If you have edited any PSyclone-related code (e.g. PSyKAl-lite, Kernel interface, optimisation scripts, LFRic data structure code) then please contact the HPC Optimisation Team

Sci/Tech Review

• I understand this area of code and the changes being added
• The proposed changes correspond to the pull request description
• Documentation is sufficient (do documentation papers need updating)
• Sufficient testing has been completed

(Please alert the code reviewer via a tag when you have approved the SR)

Code Review

• All dependencies have been resolved
• Related Issues have been properly linked and addressed
• CLA compliance has been confirmed
• Code quality standards have been met
• Tests are adequate and have passed
• Documentation is complete and accurate
• Security considerations have been addressed
• Performance impact is acceptable

[Maggie (maggiehendry)]

Sorry Douglas Clark (@doucla), I can't run the LFRic app Rose stem as this is at a more advanced version to the JULES branch. The JULES branch will need updating to be at least MetOffice/jules@332ca85 so the JULES branch is three commits behind. I also suspect the LFRic coupled Rose stem test won't run as a result of memory issues, which I was trying to test when I discovered the version incompatibility.

[Maggie (maggiehendry)]

Hi Douglas Clark (@doucla). I created a bob of your branch as I was getting the following error in the LFRic coupled tests

lib-4211 : UNRECOVERABLE library error 
  A WRITE operation tried to write a record that was too long.

After ensuring that the same test worked with the same revisions without your lfric_apps & jules branches and after going down a rabbit hole looking at all the write statements and seeing nothing wrong with them, I thought to run the developer group and not just lfric_atm_coupled_ex1a_developer. There were generate_weights* failures so I upgraded to include this fix. It seems to have also fixed the error above even though the same revisions without your lfric_apps & jules branch changes passed... the mains thing is, your lfric_apps and MetOffice/jules#143 branches pass the developer tests once upgraded to include main fixes.

[iboutle]

The issue with write statements was fixed by #874 - it was caused by pathnames overflowing the character limit in nemo, so was only triggered if you had a particularly long suite name

[Maggie (maggiehendry)]

Can you highlight the hardwired values in the PR summary please.

[Douglas Clark (doucla)]

Can you highlight the hardwired values in the PR summary please.

Done.