Improved blending of 1D and 3D turbulence schemes by Adrian-Lock · Pull Request #752 · MetOffice/lfric_apps

Adrian Lock (Adrian-Lock) · 2026-09-02T11:24:17Z

PR Summary

Sci/Tech Reviewer: Shusuke Nishimoto (@mo-snishimoto)
Code Reviewer: Ricky Wong (@mo-rickywong)

RMED problem #111 and development ticket #113 document problems found with the scale-aware wind gust diagnostic (stash 3515) that are much improved by these revisions to the method= 'blend_cth_shcu_only' option for how the 1D column and 3D Smagorinsky turbulence schemes are blended as a function of resolution. There is also potential for small benefit from including an additional new option (cap_blended_ml) to cap the blended length scale to be at most the physical length scale from the 1D scheme.

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 - testmain_blending_opt4/run1

Suite Information

Item	Value
Suite Name	testmain_blending_opt4/run1
Suite User	adrian.lock
Workflow Start	2026-09-09T21:53:29
Groups Run	developer

Dependency	Reference	Main Like
casim	MetOffice/casim@2026.07.1	True
jules	MetOffice/jules@2026.07.1	True
lfric_apps	Adrian-Lock/lfric_apps@testmain_blending_opt4	False
lfric_core	MetOffice/lfric_core@3e965e8	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@9fc2b6d	True

Task Information

❌ failed tasks - 3

Task	State
check_lfric_atm_ral_dev-seuk_MG_azspice_gnu_fast-debug-32bit-crun1	failed
check_lfric_atm_ral_dev-seuk_MG_ex1a_cce_fast-debug-32bit-crun1	failed
kgo_groups_checker	failed

✅ succeeded tasks - 1220

⌛ waiting tasks - 2

Task	State
housekeep_azspice	waiting
housekeep_ex1a	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 (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

…hallow CTH instead of zhpar

iboutle

Thanks Adrian,

My main comment is around the new test being introduced. blopt4 is a bit opaque, especially given this magic number doesn't really mean anything in the lfric namelist. But also, I'm reluctant to end up with a plethora of different tests for every individual namelist option. So...

how about calling the test raldev, and it can be built on with other things aimed at future RAL releases
In the optional config, instead of duplicating everything from the ral3 config, just include the bits which you need that are different from the ral3 config, and then include both when setting up the test.
Call the optional config something descriptive like blend_shcu or suchlike.
- To get the metadata checker not to fail, you may have to include slightly more than you need here, as it needs to be a valid config that can be applied to the base app. That probably just means including the options needed to switch Smagorinsky on, since that is off in the base app.

Thanks!

…w options under a better named blend_shcu opt file

Adrian Lock (Adrian-Lock) · 2026-09-25T14:39:51Z

Sorry, that was co-pilot's suggestion to rename the branch, which it claimed would mean github would then automatically update the PR to the new name. Rather than close the PR, which is what it actually did! Presumably it interpreted the rename as a deletion of the vn3.2 branch.
At least it would let me reinstate the old vn3.2 branch and then reopen this PR.
Interestingly I now have a copy of my vn3.2 branch ("main_blending_opt4" that I attempted to rename it to) but that's going to be even more confusing if I upgrade my vn3.2 branch to main, so I'll just delete that one! Sorry about this...

Adrian, Have you been using CoPilot on this change? you haven't marked the summary as using AI assistance and you need to be explicit about what AI assistance you were using. Policy on this is still unclear, I think Yash may be putting an update out. This may have to be on hold until the situation has some clarity.

No CoPilot, or other AI, was used on the code change at all. I tried taking advice from CoPilot on how to merge my vn3.2 branch up to main in a separate branch but keeping the same PR. But that turned out to be bad advice that I reverted and just upgraded my "vn3.2"-named branch to main instead.

Co-authored-by: Ricky Wong <141156427+mo-rickywong@users.noreply.github.com>

Agreed it wasn't clear - I hope this rephrase is ok?

Second attempt to get this comment making sense

Another tweak to the phrasing

Adrian Lock (Adrian-Lock) · 2026-09-25T15:52:13Z

Thanks Ricky Wong (@mo-rickywong) for spotting all those. I've had a go at fixing them, mostly taking your suggestions but having a go at my own word-smithing in others. Are those ok now? In case you find it helpful, the full set of changes I've made are here

Ricky Wong (mo-rickywong)

Few other changes spotted

Ricky Wong (mo-rickywong) · 2026-09-29T09:41:58Z

Suggested change

description=Smagorinsky(Smag) subgrid mixing scheme option

Values titles have been abbreviated inconsistently for space I presume. Add the short hand and make titles consistent (the fully word is in the help as it should be)

Ricky Wong (mo-rickywong) · 2026-09-29T09:42:43Z

-values='3d_smag', '2d_smag', 'blend_smag_fa','blend_1dbl_fa'
+trigger=namelist:mixing=shallow_cu_maxtop: 'blend_cth_shcu_only' ;
+       =namelist:mixing=cap_blended_ml: 'blend_smag_fa', 'blend_1dbl_fa', 'blend_cth_shcu_only' ;
+value-titles=3D Smagorinsky, 2D Smagorinsky + 1D BL, Blended scheme + Smag above,


Suggested change

value-titles=3D Smagorinsky, 2D Smagorinsky + 1D BL, Blended scheme + Smag above,

value-titles=3D Smag, 2D Smag + 1D BL, Blended scheme + Smag above,

Ricky Wong (mo-rickywong) · 2026-09-29T09:46:25Z

+help=Cap the magnitude of the blended 1D-3D mixing length
+    =by the 1D mixing length.


Just a comment, the way this reads, to the unfamiliar reader it the D could be read as "Dimensional", consider rewording?

Actually re-reading this, not sure it makes to me, please reword.

I've tried a wholesale reworking of this help, which I hope is clearer - thanks for pointing out

Ricky Wong (mo-rickywong) · 2026-09-29T09:47:10Z

+
+[namelist:mixing=cap_blended_ml]
+compulsory=true
+description=Cap the blended mixing length by the 1D


Suggested change

description=Cap the blended mixing length by the 1D

description=Cap the blended mixing length at 1D

Ricky Wong (mo-rickywong) · 2026-09-29T09:49:40Z

+compulsory=true
+description=Max. permitted cloud top height for shallow cloud blending
+help=The maximum permitted cloud top height (in metres) for shallow cumulus clouds
+    =to be diagosed.  This is used in the blending weight length-scale calculation


Suggested change

=to be diagosed. This is used in the blending weight length-scale calculation

=to be diagnosed. This is used in the blending weight length-scale calculation

More improvements to the meta data and help panels

Adrian Lock (Adrian-Lock) · 2026-09-30T08:28:14Z

Thanks again, Ricky Wong (@mo-rickywong), for spotting those. Hopefully all covered in this latest commit

Adrian Lock (Adrian-Lock) · 2026-10-15T11:07:04Z

Hi Ricky Wong (@mo-rickywong), I just spotted this PR is down as "with the developer to make changes". I'd attempted to respond to your comments 2 weeks ago but have no idea how to revert the PR to "in code review", if that's even something I'm meant to do. Apologies for not understanding the process well enough but it would be good to get this PR through your review, even if we are thinking of waiting until after #742 for the commit. Thanks

James Bruten (james-bruten-mo) · 2026-10-15T11:11:10Z

Hi Ricky Wong (Ricky Wong (@mo-rickywong)), I just spotted this PR is down as "with the developer to make changes". I'd attempted to respond to your comments 2 weeks ago but have no idea how to revert the PR to "in code review", if that's even something I'm meant to do. Apologies for not understanding the process well enough but it would be good to get this PR through your review, even if we are thinking of waiting until after #742 for the commit. Thanks

Hi Adrian,

When you're ready for another review, please click the little "circle" icon next to their name in the top right. That'll then set the state back to Review and notify the reviewer

Ricky Wong (mo-rickywong) · 2026-10-15T15:05:15Z

There is still requested changes over looked, minor case settings. These were in the previous passes, I've not added new requests. There isn't anything fundamentally wrong as far as I can see with the rest of it, though was waiting to getting to running green on trunk before approving and putting on the queue for commit.

Ricky Wong (mo-rickywong)

Not sure if git is submitting these or not

Adrian Lock (Adrian-Lock) · 2026-10-15T16:05:26Z

There is still requested changes over looked, minor case settings. These were in the previous passes, I've not added new requests. There isn't anything fundamentally wrong as far as I can see with the rest of it, though was waiting to getting to running green on trunk before approving and putting on the queue for commit.

I've added a comment against that particular request now, hoping my changed phrasing is good enough? Happy to iterate, though

Adrian Lock (Adrian-Lock) · 2026-10-22T12:19:09Z

Thanks for chasing Ricky Wong (@mo-rickywong) and I hope I have now covered all your concerns. I'm not sure of the protocol but I'm assuming I leave it to you to formally "resolve" the comments?

Ricky Wong (mo-rickywong) · 2026-10-22T12:20:04Z

Looks to have updated, the new kgo file is failing at head of trunk so it will need a KGO update on commit.

Approved

Ricky Wong (mo-rickywong)

Looks okay now

Adrian Lock (Adrian-Lock) added 6 commits June 30, 2026 18:41

Add meta data fro blending option 4

878b733

Bug fixes

ab43d37

Extras for blending opt4: include blended L cap by 1d L; use actual s…

3a5cf6e

…hallow CTH instead of zhpar

Add code needed in bdy_expl2

3874e79

Put mixing length cap on its own switch, cap_blended_ml

270f63c

Merge branch 'vn3.1_blending_opt4' into vn3.2_blending_opt4

ab7db55

github-actions Bot assigned Adrian Lock (Adrian-Lock) Sep 2, 2026

github-actions Bot added the cla-modified The CLA has been modified as part of this PR - added by GA label Sep 2, 2026

Adrian Lock (Adrian-Lock) added 7 commits September 2, 2026 13:07

Add upgrade macro

813ed93

Add new code documentation

da7a76a

Add rose stem test for new options

60dcdc6

Add rose stem test resources

ffb8522

Add checksums for new rose stem tasks

c6fdd1f

Fixes for unit tests

0fb3ab2

And add my other new namelist variable to the unit tests

d0f6bcd

Adrian Lock (Adrian-Lock) mentioned this pull request Sep 4, 2026

Import of high order turbulence closure scheme #734

Open

17 of 28 tasks

Adrian Lock (Adrian-Lock) marked this pull request as ready for review September 7, 2026 09:41

Adrian Lock (Adrian-Lock) requested review from David Lee (davelee2804), iboutle, James Bruten (james-bruten-mo), thomasmelvin and Wolfgang Hayek (tinyendian) as code owners September 7, 2026 09:41

github-actions Bot requested a review from Shusuke Nishimoto (mo-snishimoto) September 7, 2026 09:41

Adrian Lock (Adrian-Lock) added this to the Autumn 2026 milestone Sep 7, 2026

iboutle requested changes Sep 7, 2026

View reviewed changes

Adrian Lock (Adrian-Lock) added 5 commits September 7, 2026 16:24

Following reviewer suggestion to add a ral_dev task and include my ne…

b44202e

…w options under a better named blend_shcu opt file

Correct name of opt file

0ae3208

Change name to cumulus_cth, as suggested by sci-tech reviewer

f625c55

Manual merge from MetOffice#730, increase build times on AzSpice

ca0fc68

Add checksum for new ral_dev task

883e980

Adrian Lock (Adrian-Lock) and others added 7 commits September 25, 2026 16:06

Update science/gungho/rose-meta/lfric-gungho/HEAD/rose-meta.conf

fd7c127

Co-authored-by: Ricky Wong <141156427+mo-rickywong@users.noreply.github.com>

Updates to rose-meta.conf from code review

deef98d

Apply suggestion from @mo-rickywong

1963746

Co-authored-by: Ricky Wong <141156427+mo-rickywong@users.noreply.github.com>

Apply suggestion from @mo-rickywong

eab63a8

Co-authored-by: Ricky Wong <141156427+mo-rickywong@users.noreply.github.com>

Update ex_coef.F90

b499158

Agreed it wasn't clear - I hope this rephrase is ok?

Update ex_coef.F90

bea6d4e

Second attempt to get this comment making sense

Update rose-meta.conf

26c0353

Another tweak to the phrasing

Ricky Wong (mo-rickywong) requested changes Sep 29, 2026

View reviewed changes

Adrian Lock (Adrian-Lock) mentioned this pull request Sep 30, 2026

Refactor BL use GH Copliot to remove the j index #742

Open

15 of 28 tasks

Update rose-meta.conf

fdad8b1

More improvements to the meta data and help panels

github-actions Bot added the cla-modified The CLA has been modified as part of this PR - added by GA label Sep 30, 2026

Adrian Lock (Adrian-Lock) requested a review from Ricky Wong (mo-rickywong) October 15, 2026 12:09

Ricky Wong (mo-rickywong) requested changes Oct 15, 2026

View reviewed changes

Adrian Lock (Adrian-Lock) requested a review from Ricky Wong (mo-rickywong) October 15, 2026 16:05

lowercase min

5ab3f6e

Ricky Wong (mo-rickywong) approved these changes Oct 22, 2026

View reviewed changes

James Bruten (james-bruten-mo) added 3 commits October 23, 2026 13:23

Merge branch 'main' into vn3.2_blending_opt4

4404a1c

apply macros

bddc22b

update kgos

91963a7

github-actions Bot removed the cla-modified The CLA has been modified as part of this PR - added by GA label Oct 23, 2026

James Bruten (james-bruten-mo) merged commit cb385a8 into MetOffice:main Oct 23, 2026
5 checks passed

	value-titles=3D Smagorinsky, 2D Smagorinsky + 1D BL, Blended scheme + Smag above,
	value-titles=3D Smag, 2D Smag + 1D BL, Blended scheme + Smag above,

		help=Cap the magnitude of the blended 1D-3D mixing length
		=by the 1D mixing length.

	description=Cap the blended mixing length by the 1D
	description=Cap the blended mixing length at 1D

	=to be diagosed. This is used in the blending weight length-scale calculation
	=to be diagnosed. This is used in the blending weight length-scale calculation

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PR Summary

Code Quality Checklist

Testing

trac.log

Test Suite Results - lfric_apps - testmain_blending_opt4/run1

Suite Information

Task Information

Security Considerations

Performance Impact

AI Assistance and Attribution

Documentation

PSyclone Approval

Sci/Tech Review

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Adrian Lock (Adrian-Lock) commented Sep 30, 2026

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Adrian Lock (Adrian-Lock) commented Sep 2, 2026 •

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