Safely compute height fields for continuous function spaces

[tommbendall]

PR Summary

Sci/Tech Reviewer: @jameskent-metoffice
Code Reviewer: @allynt

This PR contains KGO changes from the linked ticket LFRic-Core #284, which fixes the sci_get_height kernel.

Continuous height fields (e.g. W2) change at the bit-level, causing KGO changes to any test that uses these fields. The science impact is entirely neutral however.

Linked-To

• LFRic-Core #284
• JCSDA-internal/lfric-jedi #1226
• MetOffice/jjtests #152

Blocks

• LFRic-Core #238
• LFRic-Apps #179
• LFRic-Apps #180

Results

Comparing plots from gungho_model and lfric_atm tests for this branch and vn3.1 shows that the science impact is minimal:

• results_height_continuous_gungho.pdf
• results_height_continuous_lfric_atm.pdf

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

Test Suite Results - lfric_apps - height_continuous_apps/run5

Suite Information

Item	Value
Suite Name	height_continuous_apps/run5
Suite User	thomas.bendall
Workflow Start	2026-03-09T13:39:15
Groups Run	all

Dependency	Reference	Main Like
casim	MetOffice/[email protected]	True
jules	MetOffice/[email protected]	True
lfric_apps	tommbendall/lfric_apps@TBendall/HeightContinuous	False
lfric_core	tommbendall/lfric_core@TBendall/HeightContinuous	True
moci	MetOffice/[email protected]	True
SimSys_Scripts	MetOffice/[email protected]	True
socrates	MetOffice/[email protected]	True
socrates-spectral	MetOffice/[email protected]	True
ukca	MetOffice/[email protected]	True

Task Information

✅ succeeded tasks - 1511

Security Considerations

• I have reviewed my changes for potential security issues
• Sensitive data is properly handled (if applicable)
• Authentication and authorisation are properly implemented (if 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 TCD 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

[adammaycock]

There is a change to kgo here, so likely to change kgos in lfric-jedi. @DanStoneMO can you test / update this from lfric-jedi perspective?

[jameskent-metoffice]

This PR runs the LFRic Apps tests for the linked core ticket. The kgos all change, but these are bit level changes and as shown in the helpful plots attached to the PR, there are not any science changes (the plots all look like main). Therefore this passes science review.

[ss421]

There is a change to kgo here, so likely to change kgos in lfric-jedi. @DanStoneMO can you test / update this from lfric-jedi perspective?

Thanks @adammaycock - adding linked label while we test. PR to follow if it is required.

[thomasmelvin]

Missing KGO's are back, so i'm happy

[thomasmelvin]

Im not sure why these files appear to have been deleted (the same comment applies to all the C48 baroclinic tests)

[DanStoneMO]

JEDI-side PRs are now up at:
https://github.com/JCSDA-internal/lfric-jedi/pull/1226
https://github.com/MetOffice/jjtests/pull/152

I'll approve our review shortly if there's no other concerns from us @ss421 @adammaycock

[ss421]

JEDI-side PRs are now up at: JCSDA-internal/lfric-jedi#1226 MetOffice/jjtests#152

I'll approve our review shortly if there's no other concerns from us @ss421 @adammaycock

Thanks, it looks good to me. Perhaps it would be worth updating the Linked-To section of the PR summary here?