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

mediator/esmFldsExchange_access_mod.F90

mediator/med.F90

mediator/med_phases_post_atm_mod.F90

anton-seaice · 2026-02-03T04:37:54Z

mediator/med_phases_post_atm_mod.F90

+   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

mediator/esmFldsExchange_access_mod.F90

anton-seaice · 2026-02-03T04:54:21Z

mediator/esmFldsExchange_access_mod.F90

+      ! 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

mediator/esmFldsExchange_access_mod.F90

+      ! ---------------------------------------------------------------------
+      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')

mediator/esmFldsExchange_access_mod.F90

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

mediator/CMakeLists.txt

 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

mediator/med_phases_post_atm_mod.F90

+
+      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 ?

kieranricardo · 2026-02-24T05:15:05Z

@anton-seaice this edge case doesn't occur in CM3. CICE zaps small ice fractions and the UM considers ocean fractions <0.01 as land, which limits how small ice_frac_cat_ptr can be here.

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.

mediator/esmFldsExchange_access_mod.F90

anton-seaice · 2026-03-13T00:12:20Z

mediator/esmFldsExchange_accessesm_mod.F90

+      ! to med: masks from components
+      !----------------------------------------------------------
+      call addfld_from(compocn, 'So_omask')
+      call addfld_from(compice, 'Si_imask')


Suggested change

call addfld_from(compice, 'Si_imask')

if (is_local%wrap%comp_present(compice)) then

call addfld_from(compice, 'Si_imask')

endif

?

anton-seaice · 2026-03-13T00:12:32Z

mediator/esmFldsExchange_accessesm_mod.F90

+      !=====================================================================
+
+      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 :)

mediator/esmFldsExchange_accessesm_mod.F90

mediator/esmFldsExchange_access_mod.F90

mediator/esmFldsExchange_accessesm_mod.F90

mediator/esmFldsExchange_access_mod.F90

anton-seaice · 2026-03-13T03:03:58Z

mediator/esmFldsExchange_access_mod.F90

+      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.

mediator/esmFldsExchange_access_mod.F90

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.

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

field name changes

f029178

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

mediator/esmFldsExchange_access_mod.F90 Outdated Show resolved Hide resolved

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

	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

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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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kieranricardo commented Feb 24, 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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