Bug in AOD diagnostics

[alanjhewitt]

PR Summary

Sci/Tech Reviewer: @melissaebrooks
Code Reviewer: @cameronbateman-mo

I developed aerosol AOD diagnostics in FCM 440

The outputs looked fine at low resolution, but recent high resolution modelling has indicated that I got the addressing wrong.

I made a bug fix branch in FCM 1089 and will now fix it in GitHub branch.

Code Quality Checklist

(Some checks are automatically carried out via the CI pipeline)

• I have performed a self-review of my own code
• My code follows the project's style guidelines
  style guidelines
• Comments have been included that aid undertanding and enhance the
  readability of the code
• My changes generate no new warnings

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 (eg. kgo changes)
• I have added tests to cover new functionality as appropriate (eg. system
  tests, unit tests, etc.)
• Any new tests have been assigned an appropriate amount of compute resource
  and have tests 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 - AOD_bug/run2

Suite Information

Item	Value
Suite Name	AOD_bug/run2
Suite User	alan.j.hewitt
Workflow Start	2025-12-16T16:00:21
Groups Run	developer

Dependency	Reference	Main Like
casim	MetOffice/casim@2025.12.1	True
jules	MetOffice/jules@2025.12.1	True
lfric_apps	alanjhewitt/lfric_apps@AOD_bug	False
lfric_core	MetOffice/lfric_core@2025.12.1	True
moci	MetOffice/moci@2025.12.1	True
SimSys_Scripts	MetOffice/SimSys_Scripts@2025.12.1	True
socrates	MetOffice/socrates@2025.12.1	True
socrates-spectral	MetOffice/socrates-spectral@2025.12.1	True
ukca	MetOffice/ukca@2025.12.1	True

Task Information

❌ failed tasks - 1

Task	State
run_gungho_model_robert-moist-smag-BiP100x8-10x10_azspice_gnu_fast-debug-64bit	failed

✅ succeeded tasks - 1102

Task	State
build_adjoint_tests_azspice_gnu_fast-debug-64bit-rsolver64	succeeded
site_validator	succeeded
style_checker	succeeded
test_launch-exe	succeeded
validate_rose_meta	succeeded

⌛ waiting tasks - 1

Task	State
housekeep_azspice	waiting

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 (eg. PsyKAl-lite, Kernal
  inteface, optimisation scripts, LFRic data structure code) then please
  contact the
  tooscollabdevteam@metoffice.gov.uk

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

[alanjhewitt]

This is what the bug looked like before the fix. Melissa Brooks has rerun the high resolution suite with the fix (albeit in fcm) and it now looks correct

[melissaebrooks]

I understand this area of code and the changes being added

• Yes
  The proposed changes correspond to the pull request description
• Yes, the proposed change is small, specific, and addresses the mal-addressed AOD diagnostics.
  Documentation is sufficient (do documentation papers need updating)
• Yes, this is a bugfix that correctly matches code behaviour to the expected/documented behaviour
  Sufficient testing has been completed
• Yes, the diagnostics have been added to rose stem. The code change is identical to my internal branch: lfric_apps/main/branches/pkg/Config/r14571_vn2.2_GC6beta2_aod_diag_fix which produced the screenshots in review (and has completed an AMIP run).

[yaswant]

@melissaebrooks - apologies you had to submit your review this way due to permission issues. I've just sent you an invite to join SimSys SciTech reviewer pool. Once accepted you should be able to check the items in the PR body.