# COSIMA TWG Meeting Minutes 2024 **URL:** \ **Category:** TWG\ **Tags:** meeting, twg, notes, minutes\ **Created:** [17 January 2024 05:11 UTC](https://forum.access-hive.org.au/t/cosima-twg-meeting-minutes-2024/1734 "2024-01-17T05:11:58Z")\ **Posts on this page:** 1\ **Showing post:** 21
**Author:** ![anton](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.access-hive.org.au/anton/32/1836_2.png) [@anton](https://forum.access-hive.org.au/u/anton)\ **Post date:** [4 December 2024 02:34 UTC](https://forum.access-hive.org.au/t/cosima-twg-meeting-minutes-2024/1734/21 "2024-12-04T02:34:03Z")
TWG - 4 Dec 2024 Attendees: @MartinDix , @anton, @aekiss , @ezhilsabareesh8 , @helen , @cbull , @minghangli , @sofarrell , @angus-g [OM3-0.25 Project Board](https://github.com/orgs/ACCESS-NRI/projects/24/views/1) - Chris and others - We are going to check the project board at weekly meetings to keep us focussed towards the 0.25 release - Please fix the component labels for issues & correct any missing issues and their status [CICE C-grid instability](https://github.com/CICE-Consortium/CICE/issues/992) - Anton - Anton is still investigating the crash in the 0.25 degree configuration using CICE C-grid. - Many perturbation experiments don’t crash, with various levels of instability persisting - Its likely to the instability is as described in Lipscomb et al. 2007 - Anton is still working to confirm it’s not a coupling instability, although this is unlikely. - There are many variables we are changing for other reasons which may mean the model will run ok with C-grid, e.g. update grid/bathymetry, move to 1080 barotropic timestep, JRA55 version 1.5 - It would be nice to figure out how hard to would be to [run ocn & sea-ice components serially](https://github.com/COSIMA/access-om3/issues/248), although we don’t this this is viable for long runs due to performance reasons. Performance - load balance (Minghang) Has found the load imbalance for 0.25 degree needs more work - @manodeep (ACCESS-NRI SW Transformation) has provided some input on this. Acknowledgments (Chris) - We need to clarify who is best to acknowledge for projects, especially ACCESS-OM2, where ACCESS-NRI took on COSIMA products. Meeting happening this afternoon to formalise content for [cosima page](https://cosima.org.au/index.php/get-involved/) OM2 0.1degree runs (Minghang) - Need to clarify what the significant known issues are which would be improved by using the new ACCESS-NRI took release executable & config, rather than the historical cosima executable and data. @aekiss clarified this after the meeting, see [1]. - Goal is to provide a new reference run for researchers to compare their own runs against. - We might update the RYF forcing to using JRA1.5, but otherwise won’t do any fixes to the currently released configuration. Training schedule (Chris) - [Chris has started a training schedule for informal sessions to be delivered to/with cosima for 2025, will circulate to TWG members for feedback](https://anu365-my.sharepoint.com/:x:/g/personal/u1164007_anu_edu_au/ESNybi3AdkFHrQJGyE3phtIBVhLEcqCw8craAhP4FBL8OA). Next meeting: 18th Dec - Anton chair, Chris minutes [1] Here’s a diff of the relevant commits. - [Comparing COSIMA:01deg\_jra55v13\_ryf9091..aekiss:release-01deg\_jra55\_ryf · COSIMA/01deg\_jra55\_ryf · GitHub](https://github.com/COSIMA/01deg_jra55_ryf/compare/01deg_jra55v13_ryf9091..aekiss:01deg_jra55_ryf:release-01deg_jra55_ryf?expand=1#diff-4641349c3202e76b127230aafcfaf6953053669844cd084f002be30b395ebf04) and namelist tables - MOM\_input [full table](https://github.com/COSIMA/access-om3-doc/blob/main/tables/MOM_input/ACCESS-OM2_01deg_jra55v13_ryf9091_nml.md) and [diffs](https://github.com/COSIMA/access-om3-doc/blob/main/tables/MOM_input/ACCESS-OM2_01deg_jra55v13_ryf9091_nml_diff.md) - ice\_in [full table](https://github.com/COSIMA/access-om3-doc/blob/main/tables/ice_in/ACCESS-OM2_01deg_jra55v13_ryf9091_nml.md) and [diffs](https://github.com/COSIMA/access-om3-doc/blob/main/tables/ice_in/ACCESS-OM2_01deg_jra55v13_ryf9091_nml_diff.md) Many of the differences don’t change the science, e.g. omitting parameters when they have the default value. Sec 5 of the [tech report](https://github.com/COSIMA/ACCESS-OM2-1-025-010deg-report) gives explanation for many of these. Re: JRA55 updates. There’s info on JRA55-do v1.5.0 in these two issues [JRA55 cyclones with incorrect sign · Issue #186 · COSIMA/access-om2 · GitHub](https://github.com/COSIMA/access-om2/issues/186) and [Support for JRA55-do v1.5.0 and v1.5.0.1 to get forcing up to ~present day · Issue #247 · COSIMA/access-om2 · GitHub](https://github.com/COSIMA/access-om2/issues/247). The backwards cyclones don’t affect RYF9091 [JRA55 cyclones with incorrect sign · Issue #186 · COSIMA/access-om2 · GitHub](https://github.com/COSIMA/access-om2/issues/186#issuecomment-581737733) and neither will the other fixes (see sec C.11 [here](https://climate.mri-jma.go.jp/pub/ocean/JRA55-do/docs/v1_5-manual/User_manual_jra55_do_v1_5.pdf)) so I think RYF9091 will be very similar between v1.4 and v1.5, apart from whatever lingering effects the wrong cyclones ([https://jra.kishou.go.jp/JRA-55/document/anti-cyclonic\_TCs\_L\_en.txt](https://jra.kishou.go.jp/JRA-55/document/anti-cyclonic_TCs_L_en.txt)) had on the JRA55 reanalysis. --- _[View the full topic](https://forum.access-hive.org.au/t/cosima-twg-meeting-minutes-2024/1734)._