Improve moisture conservation diagnostics

[iboutle]

PR Summary

Sci/Tech Reviewer: @tommbendall
Code Reviewer: @mo-marqh

A few useful improvements to the moisture conservation diagnostic:

• make it print the total moisture, rather than just the components
• print at the start of slow physics (start of timestep)
• change the solver callipers to measure the full density change over the solver, rather than just that of the final inner/outer iteration
• remove graupel from moisture_fluxes_alg, as this is already included in snow

I've also turned the diagnostic on in one of the short lfric_atm tests

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 - qcons_diag/run2

Suite Information

Item	Value
Suite Name	qcons_diag/run2
Suite User	ian.boutle
Workflow Start	2026-03-10T14:30:12
Groups Run	developer

Dependency	Reference	Main Like
casim	MetOffice/casim@2026.03.2	True
jules	MetOffice/jules@2026.03.2	True
lfric_apps	iboutle/lfric_apps@qcons_diag	False
lfric_core	MetOffice/lfric_core@2026.03.2	True
moci	MetOffice/moci@2026.03.2	True
SimSys_Scripts	MetOffice/SimSys_Scripts@2026.03.2	True
socrates	MetOffice/socrates@2026.03.2	True
socrates-spectral	MetOffice/socrates-spectral@2026.03.2	True
ukca	MetOffice/ukca@2026.03.2	True

Task Information

✅ succeeded tasks - 1164

Security Considerations

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• 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

[DrTVockerodtMO]

Thanks Ian. The adjoint also uses this flag (although it doesn't do anything) so it should be removed there too, I've found it present in the following lines:

https://github.com/iboutle/lfric_apps/blob/613531f6c846c236e674e1cfc32e62c64bacf5a1/science/adjoint/source/algorithm/timestepping/atl_si_timestep_alg_mod.x90#L655

https://github.com/iboutle/lfric_apps/blob/613531f6c846c236e674e1cfc32e62c64bacf5a1/science/adjoint/source/algorithm/solver/adj_semi_implicit_solver_alg_mod.x90#L312

Thanks!

[iboutle]

Thanks Ian. The adjoint also uses this flag (although it doesn't do anything) so it should be removed there too, I've found it present in the following lines:

https://github.com/iboutle/lfric_apps/blob/613531f6c846c236e674e1cfc32e62c64bacf5a1/science/adjoint/source/algorithm/timestepping/atl_si_timestep_alg_mod.x90#L655

https://github.com/iboutle/lfric_apps/blob/613531f6c846c236e674e1cfc32e62c64bacf5a1/science/adjoint/source/algorithm/solver/adj_semi_implicit_solver_alg_mod.x90#L312

Thanks!

Thanks Terry - is 410ef1e what you're after?

[DrTVockerodtMO]

Thank you very much, LGTM!

[thomasmelvin]

Looks good to me

[DanStoneMO]

Can confirm this works fine with JEDI. No linked PR will be needed for LFRic-JEDI

[tommbendall]

Science Review

This all looks good to me.

It makes sense to include the conservation diagnostics in the NWP debug job. I have checked the PET log from this job and am happy that the diagnostics make sense.

I have no suggestions so am happy for this to pass science review. @mo-marqh this is ready for code review