CM3 change rc cmeps1.1.31 x by kieranricardo · Pull Request #12 · ACCESS-NRI/CMEPS

kieranricardo · 2026-02-02T23:41:15Z

Description of changes

CM3 related changes to CMEPS. This adds an "access" coupling mode and associate field exchange module. Also adds in a custom access coupling routine to "mep_phases_post_atm_mod.F90".

Specific notes

Contributors other than yourself, if any: @blimlim

Are changes expected to change answers? No, this shouldn't affect OM3.

…E cap)

Co-authored-by: Kieran Ricardo <u5824685@anu.edu.au>

anton-seaice

I didn't go through everything, but my main comment is - can we harmonise field names and code style with the rest of CMEPS

anton-seaice · 2026-02-03T04:37:54Z

+   nullify(is_local%wrap)
+   call ESMF_GridCompGetInternalState(gcomp, is_local, rc)
+
+   call ESMF_FieldBundleGet(is_local%wrap%FBImp(compice, compatm), fieldName='ia_aicen', field=ice_frac_cat, rc=rc)


Presumable we should be running the ChkErr error, most of the rest of the code does that

anton-seaice · 2026-02-03T04:54:21Z

+      ! to atm: from ocn
+      ! ---------------------------------------------------------------------
+      allocate(S_flds(3))
+      S_flds = (/'So_t', 'So_u', 'So_v'/) ! sea_surface_temperature


Suggested change

S_flds = (/'So_t', 'So_u', 'So_v'/) ! sea_surface_temperature

S_flds = (/'So_t', 'So_u', 'So_v'/)

There's lots of comments like this which are wrong or only partially complete

anton-seaice · 2026-02-03T04:56:46Z

+      ! ---------------------------------------------------------------------
+      allocate(S_flds(9))
+      S_flds = (/'Si_t', &
+                  'ia_aicen', &


Suggested change

'ia_aicen', &

'Si_ifrac_n', &

Should we try and reuse existing names for these ?

from

CMEPS/mediator/esmFldsExchange_cesm_mod.F90

Lines 1753 to 1754 in 63e4c6d

call addfld_from(compice, 'Si_ifrac_n')

call addfld_to(compocn, 'Si_ifrac_n')

Co-authored-by: Anton Steketee <79179784+anton-seaice@users.noreply.github.com>

- rename tti routine and add description - rename coupling mode to "access-esm" - delete unfinished comments - delete unused fields

anton-seaice · 2026-02-18T02:36:00Z

 project(cmeps Fortran)

-set(SRCFILES esmFldsExchange_cesm_mod.F90 med_fraction_mod.F90
+set(SRCFILES esmFldsExchange_access_mod.F90 esmFldsExchange_cesm_mod.F90 med_fraction_mod.F90


We don't use this file, so possibly this is confusing ([esmFldsExchange_hafs_mod.F90](https://github.com/ACCESS-NRI/CMEPS/blob/upstream-main/mediator/esmFldsExchange_hafs_mod.F90) isn't included, for example)

It'd be nice to be able to use the same version of CMEPS in CM3 and OM3, but this CMakeList.txt is overridden in access3-share anyway, so I could put the change there. What do you think? Then we have a mediator that can compute both CM3 and OM3 fluxes.

anton-seaice · 2026-02-18T02:41:32Z

+
+      do j = 1,lsize2
+         do i = 1,lsize1
+            if (ice_frac_cat_ptr(i, j) > 0.0) then


if ice_frac_cat_ptr is very small, won't there be a resulting overflow in ice_flux_cat_ptr ?

anton-seaice · 2026-02-26T01:20:42Z

Changed base to cmeps1.1.35-x, looks like it will merge fine

anton-seaice

Thanks @kieranricardo

I made it as far through this as I had time for.

There are some features in esmFldsExchange_cesm which are missing here and are quite useful, including the configuration option for rof->ocn mapping files and the detection of which meshes are the same. There's also lots of duplication with the addfld/addmap/addmrg with those in cesm FldsExchange.

Would it work to call esmFldsExchange_cesm first, and then in this file, only add any extra fields needed? All the fields in esmFldsExchange_cesm are wrapped in if (fldchk(...) statements, so it should just pass over any fields which are not needed.

anton-seaice · 2026-03-13T00:12:32Z

+      !=====================================================================
+
+      call addfld_to(compatm, 'So_ofrac')
+      call addfld_to(compatm, 'Si_ifrac')


Needs an if comp_present ?

I'm not 100% on this, but I think doing the fieldchecks in esmFldsExchange_accessesm_init is sufficient (which I've now added). We can advertise whatever fields we want (which is what this does), as long as we don't try to map between fields that don't exist.

Also I can't see any comp_present checks in esmFldsExchange_cesm, so I think this should work :)

anton-seaice · 2026-03-13T03:03:58Z

+      call addmrg_to(compatm, 'sstfrz', mrg_from=compice, mrg_fld='sstfrz', mrg_type='copy')
+
+      allocate(S_flds(7))
+      S_flds = (/'Si_ifrac_n', &


We should avoid redefining these lists twice and just reuse, them or set them as Parameters.

Co-authored-by: Anton Steketee <79179784+anton-seaice@users.noreply.github.com>

kieranricardo · 2026-03-16T02:08:48Z

@anton-seaice and @blimlim thanks for you reviews!

Re. using the esmFldsExchange_cesm, there's a few potential issues:

If any of the CESM fields use a different re-mapping to us this won't work (I think it will either crash, or the mappings will override each other without a guarentee of which mapping is actually used)
I'm fairly sure that this require's aofluxes to run (and crashes it is isn't run), which could potentially override the UM fluxes.
There's a potential additional maintainence burden - we'd have to keep track of which fields of ours they define, and what mappings are being used.

So I think we're better off just using our own self-contained module.

Re. the field names, most of these names were chosen to reuse existing fields in fd.yaml. Aside from rain, there aren’t many fields with the Faxa_ prefix there. Also, esmFldsExchange_cesm.F90 sometimes plays a bit fast and loose with the prefixes - e.g. Faxa_rain is exported directly to the ocean, whereas it would probably be more consistent for this to enter the mediator as Faxa_rain and then be mapped to Foxx_rain. Given that, I’m inclined to avoid introducing additional Faxa_... fields into fd.yaml, especially since the other esmFldsExchange... modules don’t fully adhere to that convention either. But I don’t feel strongly about it, so happy to go with whatever approach people think is best.

anton-seaice · 2026-03-25T03:17:00Z

+                  'Sa_u', &
+                  'Sa_v', &


'Sa_v', &

Sounds like these two are not needed? But otherwise should be mappatch_uv3d ?

Yep, I was able to delete this

anton-seaice

Shall we make an issue/issues for missing features, mostly:

-configurable rof2ocn_ice_rmap and rof2ocn_liq_rmap

I went through the remapping methods and added a few questions

anton-seaice · 2026-03-25T23:04:05Z

+    ! This is a mediator specific routine that determines ALL possible
+    ! fields exchanged between components and their associated routing,
+    ! mapping and merging
+    !---------------------------------------------------------------------


Shall we add a note here on the general approach to remapping, e.g. which method is used for which remapping ?

That might be a little complicated to capture here, but we should definitely document this.

I was just thinking, we use:

conservative remapping for states and volume fluxes (temp, area fractions, runoff etc)

patch remapping for stresses and wind
?

anton-seaice · 2026-03-25T23:10:53Z

+             fldchk(is_local%wrap%FBImp(compocn, compocn), trim(fldname), rc=rc) &
+            ) then
+            call addmap_from(compocn, trim(fldname), compatm, mapconsf, 'ofrac', 'unset')
+            call addmrg_to(compatm, trim(fldname), mrg_from=compocn, mrg_fld=trim(fldname), mrg_type='copy')


I guess So_u and So_v should be mappatch_uv3d

I think we should add an issue for these, if mappatch_uv3d works better we should use this for the stresses as well. But I think we should properly evaluate this before implementing.

We use patch for tau, so surely this should be tau too ?

the _uv3d part does seem contentious, so how about just mappatch

anton-seaice · 2026-03-25T23:20:06Z

+                  'Sa_u', &
+                  'Sa_v', &
+                  'Sa_shum', &
+                  'Sa_tbot', &


Sa_tbot from atm uses mapbilnr and So_t from ocn to atm uses consf - is that correct ?

I was able to remove Sa_tbot, so now all our state fields are using conservative remapping. Conservative remapping is useful for ice->atm, bc it gives us a good option of weighting by ice fraction (weight by ice fraction, conservatively remap, divide by ice fraction). Also, because the atmosphere is a lot coarser that the ocean/ice grid it doesn't matter too much which re-mamping we use.

kieranricardo · 2026-04-21T02:15:50Z

@anton-seaice @blimlim I've changed the coupling names around. Some choices still seem ambiguous to me, but at least we're no longer labelling fluxes from the atmosphere with Foxx!

Kieran Ricardo and others added 20 commits February 3, 2026 10:34

add access coupling options

f0f03c7

add access field exchange module

458a277

add ice to um fields

5ce16a5

update access fld exchange module to new CMEPS

641f21d

typo fix

33eee80

bufix: fixed syntax errors

76c9db9

bufix: fixed syntax errors

197998e

more logging

0725174

update CM3 CMEPS to 1.1.2

c91eabc

fix fields

3f980c7

change flux scaling

21bb9ce

scale precipitation over ocean by ocean fraction

9b8b24d

remove scaling of ice->ocn fluxes by ice fraction (scaling now in CIC…

3eea31f

…E cap)

fix precipitation merge

0e3c454

add iceberg fluxes

2e7db88

add ocean current coupling

1fa72ee

Don't run custom CESM calculations for access

fc6754c

Tidy old logging code and comments

db26dc0

Co-authored-by: Kieran Ricardo <u5824685@anu.edu.au>

Implement time-travelling ice in post atm

996d166

map wind stress atm->ocn with patch interpolation

63e4c6d

kieranricardo requested a review from a team February 2, 2026 23:43

anton-seaice reviewed Feb 3, 2026

View reviewed changes

kieranricardo and others added 4 commits February 16, 2026 10:09

Update mediator/esmFldsExchange_access_mod.F90

06629b2

Co-authored-by: Anton Steketee <79179784+anton-seaice@users.noreply.github.com>

Update mediator/esmFldsExchange_access_mod.F90

5eea76b

Co-authored-by: Anton Steketee <79179784+anton-seaice@users.noreply.github.com>

Update mediator/esmFldsExchange_access_mod.F90

7c61389

Co-authored-by: Anton Steketee <79179784+anton-seaice@users.noreply.github.com>

- check array in time travelling ice routine

da756ff

- rename tti routine and add description - rename coupling mode to "access-esm" - delete unfinished comments - delete unused fields

kieranricardo requested a review from anton-seaice February 16, 2026 03:38

kieranricardo mentioned this pull request Feb 17, 2026

Update to CMEPS with CM3 changes ACCESS-NRI/access3-share#28

Draft

add missing import

a169525

anton-seaice reviewed Feb 18, 2026

View reviewed changes

anton-seaice changed the base branch from rc-cmeps1.1.31-x to cmeps1.1.35-x February 26, 2026 01:20

kieranricardo added 4 commits March 3, 2026 12:08

revert CMakeLists.txt and Makefile

6cf9974

check ice_frac_cat_ptr > 1e-11 (puny) before division

7bc2df0

update coupled names in post_atm tti

c9e2fae

update coupling mode check

19e77ae

kieranricardo requested a review from anton-seaice March 11, 2026 04:48

anton-seaice requested changes Mar 13, 2026

View reviewed changes

blimlim reviewed Mar 16, 2026

View reviewed changes

Comment thread mediator/esmFldsExchange_access_mod.F90 Outdated

kieranricardo and others added 6 commits March 16, 2026 12:06

Indent changes

24e5ff0

Co-authored-by: Anton Steketee <79179784+anton-seaice@users.noreply.github.com>

Delete duplicate rainc and snowc

ec8cccc

Co-authored-by: Anton Steketee <79179784+anton-seaice@users.noreply.github.com>

fix comments

70deab3

fix indentation

8578c31

rename access->accessesm

e261526

delete fieldcheck

e712bea

kieranricardo added 5 commits March 16, 2026 14:57

delete unecessary fields going into CICE

929fe0f

add fieldchecks around re-mapping

581dc2e

fix syntax errors

87dde08

fix import error

1488879

fix import error

fa99a31

anton-seaice reviewed Mar 25, 2026

View reviewed changes

Comment thread mediator/esmFldsExchange_accessesm_mod.F90

anton-seaice reviewed Mar 25, 2026

View reviewed changes

kieranricardo added 2 commits March 30, 2026 16:49

map wind stress to sea-ice and remove atm->ice state fields

6501f8c

rename fields with CMEPs prefixes

07af78b

kieranricardo requested review from anton-seaice and blimlim April 21, 2026 02:16

revert Sa_duu10n to So_duu10n

44ae6a2

	S_flds = (/'So_t', 'So_u', 'So_v'/) ! sea_surface_temperature
	S_flds = (/'So_t', 'So_u', 'So_v'/)

	call addfld_from(compice, 'Si_ifrac_n')
	call addfld_to(compocn, 'Si_ifrac_n')

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kieranricardo commented Feb 2, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Description of changes

Specific notes

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anton-seaice Feb 3, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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anton-seaice commented Feb 26, 2026

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kieranricardo commented Mar 16, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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kieranricardo commented Feb 2, 2026 •

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kieranricardo commented Mar 16, 2026 •

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