ESM Working group: Meeting notes 2026

Earth System Working Group
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Notes from each meeting of the ESM Working Group are added as a reply to this topic.

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Archived meeting notes:

2023
2024/2025

3

Date: 3/2/2026
Chair: @tiloz
Participants: 16

1. Admin and resource usage

  • Welcome back: Welcome back to the ESM WG meeting series. As discussed towards the end of last year, meetings have now fully swapped to the Tuesday 10:30AM schedule, and will alternate each fortnight with the CM3 evaluation and development meetings. Make sure to follow this topic , as announcements for both types of meetings will be made there.

  • Science Presentations: We don’t have any science presentations lined up for this year, and so if you have any work that you would like to share during the ESM WG meetings, please get in contact the ESM WG co-chairs or @spencerwong. Presentations from recent conferences and workshops are welcome, as are informal updates on in progress work.

  • LG87 Resource Usage:

    • Compute allocations for each working group have been doubled to 1.5MSU this quarter. 1MSU of the ESM WG’s allocation has been assigned to proposed experiments, leaving a large amount available for additional proposals. With the increase this quarter, there may be large amounts of compute available for rebalancing from other working groups at the end of the quarter, and so if you have any experiments to run, it’s a good time to put up a proposal and get them running.
    • If you have any experiments you are interested in running with ESM WG resources, follow the proposal guidelines here to apply to use WG compute.
    • Storage usage at 65 TB of 100 TB allocation.

  • Next CM3 dev-eval meeting cancelled: The CM3 dev-eval meeting scheduled for 17 February has been cancelled as it clashes with AMOS. There will be an ESM WG meeting two weeks later on 3 March followed by a CM3 dev-eval meeting on 17 March.

  • Shared calendar invite for meetings: The shared calendar for ESM WG/CM3 Dev-eval meetings has now been updated. If you were already subscribed, the meeting invitations should now have the correct times (contact @spencerwong if there are any issues).

    If you aren’t already subscribed, please follow the instructions on the how to subscribe to a calendar feed page using the calendar URL https://outlook.office365.com/owa/calendar/463c5a6d0bba4c838dce9c57933398fb@anu.edu.au/3086e7a51b0d48ef85bee981a597274413647516456690471131/calendar.ics to add the shared calendar to your preferred application.

    The above instructions will be added in a post on the announcement page.

3. ESM1.6 updates

  • @tiloz and @RachelLaw presented updates on the ESM1.6 simulations completed over the holiday period. Key updates include the resolution of the ocean temperature drift with the ocean albedo decrease, updates to all CMI7 forcings other than ozone, and performance improvements compared to ESM1.5, with a ~40-45% increase in throughput for the same compute cost.
  • Updated configurations tested over the holiday period include: concentration driven picontrol, emissions driven picontrol, fully coupled, bgc-only, and radiation only 1%CO2 simulations, 4xCO2, flat10, and historical simulations.
  • An issue was identified in the land BGC: BGC only 1%CO2 simulations did not show the expected magnitude of increase in land carbon uptake. This has been attributed to a bug in the phosphorous leaching parameter, which depleted the phosphorus pools available to plants. This bug has now been fixed, and new simulations with increased initial pools are being run. Carbon-nitrogen only simulations are also being tested, which display the expected levels of carbon uptake.
  • Historical simulations produce a similar climate to ESM1.5, however the land carbon cycle is quite different. Several tests are being run with different settings for phosphorous limitation, wood harvests, and initial pool sizes, to help with tuning the configuration.
  • Outputs from these test simulations are available for analysis in the following locations:
    • December spinup (CNP): /g/data/p73/archive/CMIP7/ACCESS-ESM1-6/spinup/Dec25-PI-control
    • December spinup emissions driver (CNP): /scratch/p66/txz599/access-esm/archive/esm-pi-01-expt-4a4edd44
    • December spinup (CN): /g/data/p73/archive/CMIP7/ACCESS-ESM1-6/spinup/Dec25-PI-CN
    • Spinup test with phosphorous bug fix (CNP): /scratch/p66/txz599/access-esm/archive/test_pi_plss_02-expt-a9acd03a
    • 1%CO2 (CNP + phosphorous bug fix): /scratch/p66/txz599/access-esm/archive/test_1pct_04-expt-2cb54419
    • 1%CO2 (CN): /scratch/p66/txz599/access-esm/archive/testCN_1pctco2-expt-0bf72499
    • 4xCO2 (CNP with phosphorous bug): /scratch/p66/txz599/access-esm/archive/4xCO2-01-expt-822dff3c
    • Historical (CNP with phosphorous bug): /scratch/p66/rml599/access-esm/archive/hist-restart170-hist-restart170-78be432c
    • Historical (CN): /scratch/p66/rml599/access-esm/archive/test-hist-CN-test-hist-CN-3e80d641
    • Historical (CNP + phosphorous bugfix): /scratch/p66/rml599/access-esm/archive/test-hist-fixedP-test-hist-fixedP-4af5fa4d

Please feel free to correct any mistakes in these notes directly, or message @spencerwong with corrections.

Additional information

4

Date: 17/3/2026
Chair: @ctychung
Participants: 16

1. Admin and resource usage

  • Science Presentations: Spaces are regularly available for science presentations at ESM WG meetings. If you have any work that you would like to share with the community, please get in contact the ESM WG co-chairs @dkhutch, @tiloz, @ShayneM, @ctychung or @spencerwong. Presentations from recent conferences and workshops are welcome, as are informal updates on in progress work.

  • LG87 Resource Usage:

    • 1.09 MSU out of the 1.5MSU compute allocation has been used. The remaining allocation is expected to be used by proposed experiments.
    • If you have any experiments you are interested in running with ESM WG resources next quarter, follow the proposal guidelines here to apply to use WG compute.
    • Storage usage at 65 TB of 100 TB allocation.

2. CMIP 2026 community workshop

  • @ctychung presented highlights from the 2026 CMIP community workshop, including an outline of the CMIP7 future scenarios, community MIPs, the launch of the Rapid Evaluation Framework, and changes to the data conventions compared to CMIP6. A scientific highlight was the analysis of high resolution models, and the effects of resolution in reproducing observed trends. Discussions during the workshop raised questions around “operational” CMIP activities as well as the role of AI/ML.

3. Technical presentation: ESM1.6 restart creation

  • @lachlanswhyborn presented on new tools for creating ESM1.6 restarts for new land cover data.
  • In ESM1.6, the CABLE land model discretises each grid cell into tiles, which represent different surface types. Each tile has its own physical state, carrying data for variables like temperature, soil moisture, and nutrient pools. When creating a restart file which uses a new distribution of surface types, new tiles don’t automatically start off with valid data. They need to be initialised with valid and meaningful values, otherwise the model may crash or start far from equilibrium.
  • The restart creation tool provides new tiles with meaningful data for variables associate with the land such as temperature and moisture, and variables associated with the vegetation such as nutrient pools.
  • For land associated variables, surface fraction weighted means are calculated and used within each grid cell. For vegetation associated variables, a staged tile search is used to ensure that only data from relevant vegetation types are used to fill in the missing data.
  • This tool was used to set up ESM1.6 restarts for CMIP7 which used the new land cover datasets.
  • The tool is available at GitHub - ACCESS-NRI/esm1.6-scripts: Scripts and small programs related to ACCESS-ESM1.6 model and configs · GitHub, including documentation of its configuration options.

4. CMIP7 and CSIRO updates

  • @RachelLaw shared figures from the latest ESM1.6 simulations, which are expected to be CMIP7 production runs. Control, 4xCO2, 1pctCO2, and flat10 simulations are all running, and work is underway to tune the emissions driven historical simulation.
  • There hasn’t been a commitment to run the DAMIP simulations with ESM1.6 for the fast track. CSIRO likely does not have capacity to, however if you would be interested in running these simulations and have capacity to do so, please reach out to @RachelLaw.
  • CSIRO is currently facing job cuts, with a large number of cuts going to the Environment Research Unit. This will include job losses among staff working on ACCESS and ESM WG community members. There is currently a 3 week consultation, members raised whether there were avenues for the community to provide feedback on the proposal.

5. Enso focused group

  • @Dietmar_Dommenget is setting up an ENSO focused group for discussing all things ENSO related, including ENSO performance in the ACCESS models. If you are interested in being part of this group, click the bell to follow this topic on the ACCESS Hive ENSO - ACCESS Hive Community Forum, and reach out to anyone you know who may also be interested.

Please feel free to correct any mistakes in these notes directly, or message @spencerwong with corrections.

Additional information

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