Remove bare subroutines

[James Bruten (james-bruten-mo)]

PR Summary

Sci/Tech Reviewer: Erica Neininger (@ericaneininger)
Code Reviewer: Pierre Siddall (@Pierre-siddall)

Convert files which are bare subroutines into fortran modules.

This PR also renames the 2 control subroutines for clarity and to avoid potential namespace collisions. The are changed to control_standalone and control_rivers, both contained in a similarly named module.

Code Quality Checklist

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• I have performed a self-review of my own code
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Testing

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trac.log

Test Suite Results - jules - jules_add_modules/run1

Suite Information

Item	Value
Suite Name	jules_add_modules/run1
Suite User	james.bruten
Workflow Start	2026-08-04T08:17:05
Groups Run	all

Dependency	Reference	Main Like
jules	james-bruten-mo/jules@add_modules	False
SimSys_Scripts	MetOffice/SimSys_Scripts@2026.07.1	True

Task Information

✅ succeeded tasks - 676

Test Suite Results - um - um_for_jules_mods/run1

Suite Information

Item	Value
Suite Name	um_for_jules_mods/run1
Suite User	james.bruten
Workflow Start	2026-08-04T08:22:04
Groups Run	developer

Dependency	Reference	Main Like
casim	MetOffice/casim@2026.07.1	True
jules	james-bruten-mo/jules@add_modules	False
moci	MetOffice/moci@2026.07.1	True
mule	MetOffice/mule@2026.07.1	True
shumlib	MetOffice/shumlib@2026.07.1	True
socrates	MetOffice/socrates@2026.07.1	True
SimSys_Scripts	MetOffice/SimSys_Scripts@2026.07.1	True
ukca	MetOffice/ukca@2026.07.1	True
um	MetOffice/um@9c139d0	True
um_aux	MetOffice/um_aux@2026.07.1	True
um_meta	MetOffice/um_meta@2026.07.1	True

Approvals

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Task Information

✅ succeeded tasks - 895

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Technical

• JULES Code Owner
• OpenMP
• River Routing
• Rose Stem
• Rose Metadata
• Upgrade Macros

Scientific

• Surface
• Hydrology
• Vegetation
• Veg3 RED Demography
• Biogeochemistry
• Biogenic fluxes
• Fire
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[Erica Neininger (ericaneininger)]

Not a lot of issues with this - could you just put a note in the description about the separation of control subroutines for standalone and standalone_rivers please?

[James Bruten (james-bruten-mo)]

Thanks Erica, mostly sorted

[Maggie (maggiehendry)]

I was wondering why it was necessary to rename control -> standalone_control and similarly control -> rivers_control. The fcm make only includes the relevant version. The rivers standalone code shares code where possible with jules standalone and has their own versions where necessary. The control versions are now special cases.

[Erica Neininger (ericaneininger)]

Thanks for addressing those comments. Approving sci/tech

[Pierre Siddall (Pierre-siddall)]

Thanks James Bruten (@james-bruten-mo) , this looks good to me given that it most adds namespace guardrails. Approved and heading into testing shortly.