ESM working group: Meeting notes 2024

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

Make each reply a wiki post, that way other attendees can edit the notes. This can greatly reduce the burden of note-taking allowing that person to participate fully in discussions without worrying too much about missing important details.

Archived meeting notes:


13 posts were merged into an existing topic: ESM working group: Meeting notes 2023 (Archived)

Date: 7/12/2023

Participants: 13

Chair: @LaurieM


  • For the next meeting (29th) we will have a shared meeting with Forecasting and Prediction Working Group to discuss the Triple La Niña experiment, and an ACCESS-S2 User Training Workshop. Will spend 20 minutes with some discussion of where to find the data, how to analyse and some discussion of analysis and ideas for where to focus that analysis.
  • @sebmckenna happy to talk about ACCESS-CM2 pacemaker experiments.

Shared experiments/ACCESS-NRI resources

  • ACCESS-NRI Merit Allocation guidelines are available. The requirements to access time are very minimal compared to MAS applications. Come and use the resources on offer!
  • ESM project lg87 /g/data storage: 30TB used out of 50TB. 116KSU used 758KSU remaining.
  • @ariaan could use some SUs. Will put up some information about them.
  • WG needs more /g/data storage space. Take to SAC.

Freshwater forcing in sub-polar North-Atlantic

Status of @gpontes experiment.

(Apologies, the top and bottom of the video have been clipped)

Freshwater forcing in sub polar northatlantic. Just esm-ssp585-45 computed under lg87. Including historical also under /g/data/lg87.

Some issues restarting historical experiments from other runs. Reported on hive. Ran another historical ensemble for historical. Also available.

Started 4-member ensemble for historical and SSP. HI-X-grm, ssp585-X-dgrm. 2-member ensemble ssp585-X-cgrm.

@tiloz is historical a new ensemble member? Restarted from a different time? Yes.

@tiloz asking if ssp585 is concentration driven. Confirmed yes, not emissions driven.

Was using the to rebuild experiment for payu. Got a calendar error. Works fine if all processes using payu.

@ariaan did restart historical runs using payu from older non-payu runs. Might have been a date issue. @holger assisted.

@ariaan Are ensemble members of 2 and 4 enough? Need larger ensembles? Would it be good to have historical members branched further apart to have different AMOC states? Would be good to have more ensemble members.

@gpontes Could do so if community thinks it is useful. Ideally would be 10 members. Restarted experiments from 1950. Perturb IC and run 10 years, then begin FW perturbation.

@ariaan GFDL models have strong convection in southern ocean (Amundsen and Ross Seas). For some things in the deep ocean models have a specific path.

@gpontes Now investigating teleconnections between AMOC and southern ocean.

@RachelLaw ssp585 is the highest scenario. Plans for a more moderate scenario?

@gpontes Other scenarios not set up for payu. Mostly looking at coming decades. 20-30 years doesn’t matter too much. All simulations go to 2100. Focus on coming decades

@LaurieM Simuations quite idealised. Contentious about how to design the FW experiment.

@RachelLaw also having issues restarting payu from a different restart.

@gpontes could increase number of members If group wants to do it.

ACCESS-ESM1.5 – ACCESS-NRI supported release

@Aidan updated us on plans for an ACCESS-NRI supported version of ACCESS-ESM1.5. It will have:

  • spack build system
  • build-CI testing
  • released experimental configurations utilising payu
  • full experiment provenance
  • automated reproducibility testing

This topic on the forum gives an overview of the project and will be used as the main place to find information about the progress of the release

(Apologies, the top and bottom of the video have been clipped)

What’s going on?

@RachelLaw: the CMIP panel want feedback on the AR7 fast-track design

This is a wiki post , if you want to update any of the details in these meeting notes, or to add your own recollection of what was discussed then edit me rather than replying.

Date: 29/02/2024

Participants: 26

Apologies: @JulieA

Chair: @eunpalim

Shared Section

1. Introductions from each group

@debbie_h: Forecasting and Prediction Working Group incorporates Machine Learning (ML), Data Assimilation (DA), seasonal forecasting. Quite disparate groups, but try to do things for each group. Had a good ML session at last workshop, has led to good collaboration since.

No common infrastructure. Not supported by ACCESS-NRI. Working on how ACCESS-NRI could support those areas. Drafting two short papers for guidance: how ACCESS-NRI could support DA into the future, and another on how to support ML into the future.

@nathan-e difficult getting cohesion with these challenges.

@LaurieM co-chair. Earth System Modelling Working Group also somewhat disjointed. Focus on the use of the coupled models: ACCESS-ESM1.5, ACCESS-CM2, also ACCESS-S2. Also interested in coupled climate. Past, future and paleo climate. Ocean/atmos interactions for El Nino. Also for future climate.

Big focus on carbon cycle. Ocean and land carbon cycles.

Last few months trying to get to know each other, find out what others are doing. All want to push forward with ACCESS suite of models. One focus has been adding flexibility of framework. Modifying forcing, particularly ancillary files. Land-sea mask and bathymetry and orography.

Collaborating closely with ACCESS-NRI. Pushing for a more user friendly workflow to expand range of activities in models.

Also want to facilitate collaboration using ACCESS suite. All co-chairs from different institutions with different scientific focus.

2. Triple La Niña experiment

The Triple La Niña experiment that was a joint initiative of the ESM Working Group (Working Group) and F&P Working Group (Working Group )

Triple La Nina of 2020-2022/23. Unusual to persist for three years. Not particularly strong, but 3rd year Australia experience severe flooding and rainfall events.

Preceeded by black summer and Huna Tonga in Jan 2022 could have contributed to persistence.

ACCESS-S real-time forecasts skilfully capture the triple dips of the La Nina event at up to 4-month lead time.

Examine effect on forecast skill of atmospheric initial conditions. Examining forecast differences in topical SST and persistent SAM.

Need 3 datasets:

  • Hindcasts (retrospective forecasts). Used to compute climatology and std dev. Also can compare to previous La Nina to assess skill
  • Standard real-time forecasts with realistic Atmosphere initial conditions
  • Experimental forecasts with unrealistic Atmosphere initial conditions
  • How to access the outputs

Hindcasts are in




Experimental forecasts


18 week forecasts (4 months). 23-member ensembles for experimental forecast.

Should we pre-compute climatology and ensemble mean and store. Would require more space.

What should we do with this data?

Peer-reviewed paper? La Nina, SAM, Australian Rainfall? Encourage ECRs?

Announce availability?

Half-day hackathon?

Who might be interested in a group study?

@dkhutch: don’t want to speak for them, but @nicolamaher and @jemmajeffree couldn’t make it, but might be interested?

NESP planning a special effort on Triple Dip La Nina. This experiment came from discussion in NESP meeting. High customer demand to understand TLN and impact on Australian Climate.

Wanted to contribute to NESP

@eunpalim will Add slides to hive.

@ctychung Plan to have stakeholder based webinar around July/August. Would be good to have results from this presented.

@eunpalim Similar experiments done by @lynnzhou for wet 2022. Large magnitude of wetness was atmosphere driven. If not having large atmospheric impacts (smoke, volcano) how much of the La Nina can we reproduce? Which is most important driver? Atmosphere or Ocean. What more important IOD, SAM? Good opportunity for ECR to understand nature of forecast data and systems.

@aidan: How important is collaboration?

@debbie_h: ACCESS-S hindcast already available. Coordination not required, but coordination is an option if that is people’s wish.

Contributing this effort to NESP would be good.

Not thinking too deep an investigation at this stage. Any contribution welcome.

Discuss possible ACCESS-S2 Training. Gauge interest and requirements

Half-day hackathon? Look at some major events and analyse together?

Ensemble and climatology need more space. Certainly possible. @Aidan:ACCESS-NRI can support training activities.

@debbie_h: Some people want to run ACCESS-S2. Tricky. No documentation. Only 3 people at Bureau can run model. Only set up for forecasting. Limited knowledge of how to do this for sensitivity and scientific experiments. Getting ACCESS-NRI involvement depends on demand. Get in touch with @debbie_h to register interest in using ACCESS-S2.

ESM Working Group Section

3. ESM WG Admin

  • @sebmckenna has volunteered to talk on "SST and ENSO biases in ACCESS-CM2 pacemakers” for the next meeting (2024-03-14T02:00:00Z)

  • We need more speakers! Message any of the co-chairs or @Aidan if you’re keen

@eunpalim: Saw good talks at AMOS. Please feel free to recycle AMOS talks in this forum. Even if seen before, always good to see again and have better understanding.

@ShayneM: putting shallow water model into ACCESS coupled model. Will talk in next few months.

@dkhutch Maybe @Dietmar_Dommenget could present on the paper he is leading and which @dkhutch is collaborating. Collaboration came from ESM WG meetings.

@rachellaw also just had a paper accepted for CMIP7 overview. Could present some slides.

  • Report from Scientific Advisory Committee (@LaurieM). Next SAC Meeting 2024-03-21T03:00:00Z

Reminder of CMIP7 ESMValTool Hackathon. March 12-14 at Aspendale. Probably too late to register. Drop-in session tomorrow.

  • If you want to suggest a topic to cover in the ESM WG meetings reply to this topic and add your idea

  • Do you know anyone who you think would benefit from coming to these meetings? Please invite them! We definitely want ECRs and students to attend too.

4. ESM Shared experiments/ACCESS-NRI resources

  • See the guidelines for accessing working resources. The requirements to access time are very minimal compared to MAS applications. Come and use the resources on offer!

  • lg87 /g/data storage quota has been doubled to 100TB. Note that this is intended for short term storage only (generally maximum of 1 year).

  • ESM project lg87 /g/data storage: 27TB used out of 100TB. 117KSU used 757KSU remaining.

Probably still don’t have a clear process for how experiments that are proposed get resources to run. Filled in proposal. then what? @Aidan: bring it up at a meeting, volunteer to begin running experiment.

5. What’s going on?

CMIP7 fast-track consultation

Need survey by the middle of next week. Put feedback on hive, contact @RachelLaw or fill in survey.

@JulieA three level B positions for new CoE. UNSW advertised now. Another at UniMelb(?) one at Monash(?).

ACCESS Hackathon clashes with next meeting. @aidan will put up a poll to gauge interest.

This is a wiki post , if you want to update any of the details in these meeting notes, or to add your own recollection of what was discussed then edit me rather than replying.

1 Like

Date: 28/03/2024

Participants: 13

Apologies: @eunpalim @ShayneM @dkhutch

Chair: @tiloz


1. Admin

We have no speakers lined up for our next meeting or any subsequent meetings. Please volunteer to speak. Message @Aidan to discuss.

@tiloz Please advertise and invite people to talk. Particularly early career researchers.

@Dietmar_Dommenget can talk about change land-sea mask results with GFDL model. Might be able to talk about the ACCESS equivalent in May.

Remember to add any items you want this WG to discuss to ideas for topics

@tiloz SAC Meeting last week. All SAC meeting notes are publicly available on website slightly delayed.

@tiloz Will be ACCESS-NRI Workshop in September (2nd-5th). Also a COSIMA workshop beginning of July. Might reduce attendance to workshop. Call for people to join workshop program committee. Structure still to be decided.

Progress towards CMIP7 and model development plans. Largely on-track. Fast track timeline very challenging.

CMIP7 Hackathon hands-on meeting to evaluate ACCESS model output using ESMValTool and iLamb. Good intro and setup. Overview of existing recipes, look at what is required. May be a follow up at the workshop.

@LaurieM Would be good to have someone from ESM WG involved. @dkhutch and @wghuneke did it last year. Can be anyone, ECR or senior scientist.

2. Shared experiments/ACCESS-NRI resources

ESM project lg87 underutilised. 195KSU remaining out of 405KSU grant (rest reallocated to other projects). 30TB our of 100TB used of quota on /g/data/

@tiloz storage allocation is short-term for duration of experiment. Need to have a long term plan for where it will reside.

@clairecarouge presented plan to manage lg87 /g/data storage. Easier to manage storage if people write into a specific location for an experiment. Experiment folder created, can work however you want underneath.

Do want to have some data folders for slightly longer term storage. Would need to be of use to the community and decided by the working group.

To help with organisation will have a writer group, only those who are members can write by default. Others can only write to their own experiment folders to prevent data loss.

Was hoping to be ready for Q2, not quite ready yet. All admins will have write access to all data to enable clean-up.

Writer group will be some ACCESS-NRI, and hopefully some from community who want to be involved. Won’t be a large workload. No previous knowledge required.

Please put your experiment proposals on the hive. Great opportunity to access NCI compute resources. See guidelines for how to do this.

David (@dkhutch) and Dietmar (@Dietmar_Dommenget) are running experiments under lg87. @Dietmar_Dommenget: Running 4x400 CPU experiments. First test runs to confirm results obtained from GFDL model. Idealised ocean basin configurations. Seems to be working. Will do at least 15 experiments. Roughly 1MSU. Need to run 100 years. About ENSO. First 50 years trending. Changed ocean basin sizes. Used GFDL model. Submitted paper with interesting El Niño. Wanted to do with low-res ACCESS model. @dkhutch has looked at similar problems. Managed to run Miocene configuration in ACCESS-ESM1.5. Also testing with no continents in tropics, 1, 2 or 3 oceans basins. Only managing 10-15 model years/day.

@tiloz do current model proposals meet needs of community? Need to consult with community.

@JulieA is assistance to run models in scope for ACCESS-NRI? @clairecarouge if it is an experiment that is required for model development. Otherwise no.

@Dietmar_Dommenget new experiments should have ACCESS-NRI input. Learn what users are struggling with. More than providing CPU time. Particularly novel simulations. Spending months to just move land/sea boundaries.

@LaurieM Have to be careful what we suggest. Difference between running experiments versus flexibility/application of a model. Maybe not run the experiment, but be involved in helping/documenting and moving forward. @dkhutch invested a lot of time in learning how to configure the model. Spread the knowledge on GitHub. Should we include someone from ACCESS-NRI. Should be able to take it and improve it. Could help in the community.

@tiloz model development requires substantial changes to the code and model configuration. Support is required.

@Dietmar_Dommenget ACCESS-NRI needs the level of knowledge that @dkhutch has developed. Will not help someone with the next problem. ACCESS-NRI should do this sort of work. These are essential skills that we need.

@JulieA where is the boundary between science and infrastructure. Can be very difficult to configure the model.

@tiloz boundary is blurry between scientific and infrastructure. @LaurieM ACCESS-NRI has quite clear definition of what is in-scope.

3. Science talk

Sebastian McKenna (@sebmckenna) presented “SST and ENSO biases in ACCESS-CM2 pacemakers”

ENSO appears to be a more dominant factor in Indian Ocean variability than Pacifici Ocean mean state.

Added SST perturbation to restoring file to create ensembles.

Just finished all ensemble members, still need to analyse it all.

Initial results:

  • IOD doesn’t change under different El Niño conditions
  • Basin wide warming more likely with EP El Niño

More analysis required. Determine if we need more ensemble members.

@Dietmar_Dommenget biases in Indian Ocean seem more important? Can’t test with this experimental setup? @sebmckenna can’t test with this pacemaker experiment.

@Dietmar_Dommenget what do biases look like? Mean state winds

Too warm if east Pacific and cool around Arabian Sea. Biases are seasonal. A lot of mean-state bias related to biases in wind.

@gpontes Have you evaluated teleconnection between ENSO and IOD in the model? Correct strength of feedback. @sebmckenna did look at this. Do have internally forced, ones that happen during ENSO and not. Gets both type of events. Model is more independent in the model.

@Dietmar_Dommenget IOD independent modes are weak, too strong in the models? Too sensitive/unstable. @sebmckenna most coupled models have overly strong IOD bias. Not due to remote teleconnections. Some problem with the Indian Ocean in the model.

@gpontes investigated Indian Ocean dynamics? @sebmckenna only looked at surface ocean/atmosphere interaction. Not looked below the surface. Would be good to investigate.

@Dietmar_Dommenget Atlantic could also play a role. Warm biases could also influence the tropics.

@sebmckenna in literature a lot more about Pacific/Indian Ocean interactions. @Dietmar_Dommenget what matters is the relative differences in biases. It might not be relevant, but if you have the setup interesting to see if Atlantic mean state has any influence.

@sebmckenna study by @dhb599 of Atlantic pacemakers didn’t look at Indian Ocean. Might be interesting to look at the data from that.

4. What’s going on?

@Aidan ACCESS-NRI ACCESS-ESM1.5 release is proceeding, but slower than hoped. Initially will target three configurations: pre-industrial control and two historical, concentration driven and emissions driven. Will consult the community in the near future about what configurations should be targeted once the intial release is done. This release is different from what is currently available as it will be a ground-up restructure of how the model is built, deployed and tested. Have developed the infrastructure with the ACCESS-OM2 release which is being finalised. Includes experiment provenance and tracking. In the medium term this will mean offering databases with experiment metadata that is searchable by anyone. Will apply the same methodology to ACCESS-ESM1.5. Configurations will use pre-built and deployed model binaries, but the system is very flexible and users in the community will benefit from the ability to easily build the model and change dependencies and model component versions easily. In addition these is an ACCESS-NRI supported model and configurations, so the community can ask for assistance. @tiloz this is very welcome for the development of future versions of ACCESS-ESM.

This is a wiki post , if you want to update any of the details in these meeting notes, or to add your own recollection of what was discussed then edit me rather than replying.

Date: 11/04/2024

Participants: 13

Apologies: @LaurieM @eunpalim

Chair: @ShayneM


1. Admin

  • @LaurieM has decided to step down as co-chair of the ESM Working Group. Thanks for all the work Laurie has put into establishing this working group.
  • Welcome to our new co-chair @dkhutch!
  • We currently have no volunteers to speak for the next meeting, or any subsequent meetings. Please volunteer to speak. Message @Aidan to discuss.

@spencerwong is willing to talk next (May 9th). @Dietmar_Dommenget on May 23rd.

Would like to have an interesting science talk for every meeting.

2. Shared experiments/ACCESS-NRI resources

  • ESM project lg87 has used 638KSU out of 825KSU allocation.

@Dietmar_Dommenget can use 2MSU.

@AndyHoggANU used time in last quarter. COSIMA used the bulk of the time in the last week. Better off using the quota and ask for more.

@Dietmar_Dommenget can run right now. @AndyHoggANU prepare new ones, talk to @clairecarouge and switch resources in a couple of weeks.

  • 33TB our of 100TB used of quota on /g/data/

@Dietmar_Dommenget Need maybe 10TB. @dkhutch working on archiving process. Can make it much smaller. Only keep what is scientifically relevant. Might need to store for 1 year.

Proposals for experiments for next quarter?

@Dietmar_Dommenget Will give a presentation in 2 weeks. Repeated GFDL experiments with ESM1.5. Looked at second 50 years. Results looked to have similar characteristics to low resolution GFDL. Using idealised basins. Repeating with high resolution model. Not all characteristics. @dkhutch Dietmar has been running them, but we’ve collaborated with the model setup and configuration. Drastically changed land-sea mask and worked ok. Want to reconfigure river-runoff, so not changed in these experiments. Large scale fluxes will be ok, so reasonable for these purposes.

3. Science talk

Andrew King presented “Exploring climate stabilisation at different global warming levels in ACCESS-ESM1.5.”

  • Long simulations run under net-zero CO2 to understand stabilisation processes
  • Address modelling capabilities gap from CMIP6
  • Paris Agreement aims to limit warming well below 2°C about pre-industrial which imply net-zero emissions.
  • Despite this CMIP6 do not address this well to look at implications of missing these targets
  • Experiments to address this gap. Rather than use concentration pathway turn off emissions at different times to achieve different final warming levels
  • Run ACCESS-ESM1.5 simulations to do this. Ran 7 1000 year experiments turning off CO2 increases over 5 year SSP trajectory. Look at how these climates evolve
  • Non-CO2 GHGs are fixed at PI levels
  • CO2 concentrations are determined by interactive carbon cycle, emissions are set to zero, so total CO2 concentration drops
  • The longer we delay achieving net-zero the higher the final land-ocean temperature anomaly
  • SSTs continue to rise slowly. Full Depth ocean heat continues to heat very strongly
  • Sea ice extent different between Arctic and Antarctic. Delaying net-zero reduces arctic sea ice extent. Antartica has continued sea ice extent regardless of time of net-zero emissions, still worse the later it is done
  • Sea-ice free events: arctic is just a function of amount of total warming. Antarctica has a time component also
  • Sea ice extent representation in ESMs is often biased, so caution is needed.
  • Different local responses over land and ocean. Sydney experiences significant additional warming compared to northern hemisphere cities.
  • Significant local temperature and precipitation changes post net-zero, and these grow over time
  • Preprint available:

Lots of discussion! See the video.

4. What’s going on?

@JulieA did you do CMIP6 stratospheric ozone only? @tiloz have to total ozone. LESMIP are extension of CMIP6 runs. Maybe only did ozone runs for LESMIP, not CMIP6. DAMIP ozone only was stratosphere only. Not much SAM response which is intriguing. If thinking tropospheric and stratospheric separately would be great. @sofarrell ESM1.5 is UMv7, might be limited in what is possible.

This is a wiki post , if you want to update any of the details in these meeting notes, or to add your own recollection of what was discussed then edit me rather than replying.

Date: 9/5/2024

Participants: 20

Chair: @eunpalim


1. Admin


  • Only met once so far.
  • Plan is for a similar structure to the last workshop.
  • Want to know what things went well, and any other ideas send to @dkhutch or working group chairs. Want to know how it went, and how it could be better.
  • ESM Working Group got a lot of value out of a working group meeting at last workshop. Have indicated would like another WG meeting at this workshop. Ocean and Land unlikely to have a WG meeting at the workshop. Potentially an opportunity to entrain some of the community who might otherwise attend other WG meetings.
  • Need a student representative for the organising committee. Please suggest someone else or yourself.

2. Shared experiments/ACCESS-NRI resources

  • ESM project lg87 has used 1.4MSU out of 1.9MSU allocation. We have asked, and received, two additional allocations of compute quota (total 1.1MSU extra).

Mostly used by @Dietmar_Dommenget and will use the remaining resources. There may be more resources available. @Dietmar_Dommenget could use another 1-2MSU if available.

@Dietmar_Dommenget will give a full report of the experiments in a presentation in the next meeting. Have done 3 experiments. Not yet analysed in depth, but seem to be working correctly.

3. Science talk

Spencer Wong: “Coupling a shallow water model to the UM atmosphere”

  • Couple a shallow water model (thermocline depth) to UM. Want UM interacting with thermocline anomalies the atmosphere model sees.
  • Aim is to couple a simple ocean model to a complex atmosphere, enabling idealised experiments
  • Shallow water model exists as a stand-alone implementation using a 1x1 degree between 51S and 51N. Using forced wind stress anomalies can reproduce ENSO behaviour.
  • Utilised an existing slab ocean implementation directly within UM, and replaced with shallow water model.
  • Many technical challenges: adding prognostic variables, grid differences, parallelisation issues
  • River routing model runs on a 1x1 degree grid, included prognostic variables, machinery for creating prognostic variables, serialising code and regridding routines. Copied and utilised this existing code.
  • Is a gather → calculate → scatter operation.
  • Performs much better than slab model
  • Peaks in Niño 3.4 autocorrelations are slimmer than in observations: El Niño/La Niña don’t persist as long as observed. More work required.
  • 2-3KSU for 50 year run. Throughput is 1-1.5 days per 50 years.

4. CMIP7 Update

@RachelLaw gave an update on plans for the ACCESS CMIP7 submission:

CMIP7-update-May2024.pdf (580.9 KB)

  • DECK is consistent with previous CMIP cycles with addition of historical. Note piControl and emissions-driven esm-piControl (interactive carbon cycle).
  • AR7 Fast Track is from a range of MIPs, but geared towards next IPCC report. Should be completed by end of 2026.
  • 6 scenarios. Recommendation to be emissions driven.
  • Thinking about feasible model development timeline. Still aiming for ESM3 for wider CMIP7. Hesitant about committing for fast-track.
  • ESM1.6 would derive cleanly from ESM1.5. Would be close to current configuration of CABLE but with some updates to land-use.
  • Thinking about a fast track submission with ESM1.6.
  • ESM1.6 1 degree ocean, CABLE3
  • ESM3 0.25 degree ocean, CABLE4
  • Don’t have resources for large changes to physics for ESM1.6. Do want to identify any outstanding issues or fixes.
  • The earlier the submission is in the more uptake from the community. Definitely want an ACCESS model in the fast-track. Don’t want to detract from ESM3.
  • Have not currently got the resources we would need for a more ambitious ESM3 on Fast Track timeline.
  • @JulieA Here’s a writeup from the recent CMIP meeting for those interested:
  • @Aidan Some bugs with Ocean BGC that need fixing. ESM3 should be done well, and not necessarily beholding to CMIP cycles. ESM3 might not run fast enough for Paleo work.
  • @RachelLaw scenario MIP is always higher priority and a lot of projection work flows from it. Community can run whatever MIP experiments were of interest.
  • @RachelLaw None of currently planned models go beyond N96 resolution because it is too expensive for CMIP7 but ESM3 would provide a code base for higher resolution work (e.g. for Weather of the 21st Century COE).

This is a wiki post , if you want to update any of the details in these meeting notes, or to add your own recollection of what was discussed then edit me rather than replying.

1 Like

Date: 23/5/2024

Participants: 14

Chair: @dkhutch


1. Admin

  • Speakers: Christine Chung from the Bureau has volunteered for the next meeting (June 6th). There are no speakers after that. Please do volunteer to present your science. Message co-chairs or @Aidan to discuss.
  • Remember to add any items you want to discuss in these meetings to ideas for topics
  • Save the date: ACCESS Community Workshop 2-5 September. The planning committee is seeking ideas for (a) invited speakers and (b) breakout topics. Need ESM ideas for both of those things.

@dkhutch on the planning committee. Please send @dkhutch or working group co-chairs for ideas or things you think worked well last year.

  • We need to form an organising committee for the ESM Working Group’s own workshop. Last year we had a half-day, with Wilma as lead organiser, but she is on parental leave this year.

Need ideas for topics! Please get in contact.

Plan to do a half-day ESM Workshop as same as last year.

@eunpalim Any theme? @dkhutch talking it through. One idea is CMIP7, but want to make as inclusive as possible, otherwise could exclude Paleo climate.

Will be $100 fee. Mostly about commitment and some cost recovery. Very small fraction of real cost.

@Aidan Could ACCESS-NRI cover costs for students? @dkhutch Good idea. Let them know if there is no funding.

@eunpalim After last workshop there was feedback sent to @wghuneke. Is that feedback report available? @dkhutch I’m sure we can ask Wilma for that.

2. Shared experiments/ACCESS-NRI resources

  • ESM project lg87 has used 1.74MSU out of 1.9MSU allocation. We have asked, and received, two additional allocations of compute quota (total 1.1MSU extra). Unlikely to be more available this quarter
  • 26TB our of 100TB used of quota on /g/data/
  • Any proposals for shared experiments for next quarter? See guidelines for how to do this.

3. Science talk

Dietmar Dommenget: “ENSO and tropical basin interactions in idealized worlds”

  • Authors @Dietmar_Dommenget and @dkhutch
  • Motivation: model development and ENSO dynamics
  • ENSO Experiments: GFDL CM2.1 and ACCESS-ESM1.5
  • Submitted for publication
  1. Deep paleo study (Eocene 55MYA). Rearrange land and oceans
  • Much harder than you think. Not able to do this with ACCESS-N48. Still not working after 2 years.
  • @dkhutch got ACCESS-ESM1.5 working within 1 year
  • GFDL CM2.1 took ~1 month
  • MPI(1996) took 2 weeks to change bathymetry
  1. A fast CGCM
  • ACCESS-N48 coupled GCM
  • Model biases are on par with early CM2 version
  • Want fast model (100ys/day). Want to explore climate dynamics with many 100+ years simulations.
  • Want fast run, analysis cycle
  1. ENSO dynamics
  • Why is ENSO only in the Pacific?
  • Do the other ocean basis interact with ENSO?
  • Still don’t understand all dynamics of ENSO
  • Models have different behaviour
  • Belief that other ocean basis influence the Pacific and vice-versa, but some controversy
  • Theory: larger basin = larger SST variability, larger basin = longer periods, rest of the world is irrelevant
  • Reality looks different to theory
  1. GFDL CM2.1
  • Atmos: 3° x 3.75°, Ocean 1.0° x 1.5°
  • Single tropical basin, two tropical, and three tropical basin experiments.
  • Plan to simulate eocene, but noticed it was interesting for El Niño dynamics
  • GFDL model: 15 runs was ~1MCPU and 5 days
  • ACCESS-ESM1.5: 5MCPU and 20 days
  • Would take a year to reproduce CM2.1 runs with ACCESS-ESM1.5. Would not be feasible with CMIP like models such as ACCESS-ESM1.5
  • As size increases variability increases, peaks at Pacific size, drops and then increases again at full basin width. Unexpected, and not consistent with ENSO theory. Not expected from ocean perspective, but probably related to atmospheric dynamics. Currently being studied.
  • Power spectrum: peak moves to higher frequencies the bigger the basin. This is the exact opposite of theory. Frequency lowest at Pacific size, but increase with basin size with bigger sizes.
  • Twin ocean basin experiments: two twins hugely increases variability, if one is shallow it is damped.
  • Why is there such a strong change in ENSO if there is a second deep ocean basin?
  • Single basis land is positively correlated. With shallow twin there is no correlation. Two deep basins are very strongly anti-correlated.
  • Triple basin experiments: one larger basis suppresses variability in smaller basis. All identical size variability is similar in each.
  • ENSO does not get stronger with basin size
  • ENSO depends strongly on interaction with other basins
  • ENSO theory cannot explain this

Hypothesis tropical atmospheric dynamics control ENSO

  • Larger basins lead to atmospheric rearrangement and interfere
  • Dynamical ocean basins heat fluxes can provide heat sources/sinks that land cannot
  1. ACCESS-ESM1.5
  • @dkhutch made scripts to mimic these experiments, except for one small connection.
  • Did not repeat all experiments.
  • Generally weaker. Wider basin is much weaker than GFDL2.1. Disagreement with overall variability, especially with largest basin.
  • Peak frequency looks similar, fewer data points, not as strong, but similar patterns.
  • More variability in twins with shallow sea
  • Trio experiments look similar, and larger central also damps small neighbours
  • ACCESS generally has less variability than GDL2.1
  1. Summary

Could use more resources to complete the experiments.

4. What’s going on?

@Aidan ACCESS-NRI release ACCESS-ESM1.5 progressing. ACCESS-ESM1.5 is building and deploying with ACCESS-NRI systems. Now working on configs: reorganising and adding testing and other quality control measures. Current estimate is a release at the end of June. Can then work on releasing other configurations, and will consult with this working group who will have to decide what configurations should be released and supported, and in what order.

@Dietmar_Dommenget runs crash all the time. Impinges 10 years/day rather than 90 years/day. High priority is a fast and simple model. Make it easier to change configurations easily.

All CMIP6 models are all too slow and complicated.

@gpontes are model crashes are ocean or atmosphere related? @Dietmar_Dommenget not reproducible, something with the operating system or opening files?

@gpontes have been having numeric and technical issues.

@aekiss can automatically sweep and re-run if the crashes are known and can be ignored.

This is a wiki post , if you want to update any of the details in these meeting notes, or to add your own recollection of what was discussed then edit me rather than replying.

Date: 6/6/2024

Participants: 18

Chair: @tiloz


1. Admin

  • Speakers: @HIMADRI_SAINI has volunteered to talk on the Fourth of July, but we have no speaker for the next meeting (20th June). Please consider presenting, even work in progress that you’d like some feedback. Message co-chairs or @Aidan.

Good to have feedback and visibility on what people are working on.

If you have any suggestions for ideas to talk about please do add them to the topic.

Same format as last year. Training day, 2 days of workshop, and ESM half day meeting.

@dkhutch will contact @wghuneke and get feedback from last year. Need someone to lead the working group day. This year will have combined registration for workshop and ESM WG day. Will open June 27th. So need to be organised and have something ready by then. Potential themes: CMIP7, regional modelling, paleo and ice-sheets. Want to have invited speakers lined up in time for registration. CMIP7 will likely be around Australian contribution.

@tiloz doesn’t need a lot of work, just meeting enough. @dkhutch just need to get organised for registration deadline.

@aidan Training opportunities will be part of the registration process to gauge interest and help plan training delivered.

  • Next SAC Meeting is June 20th (same day as next WG Meeting). Are there any items the Working Group would like taken to SAC?

2. Shared experiments/ACCESS-NRI resources

  • ESM project lg87 has used 1.74MSU out of 2.3MSU allocation. We have asked, and received, two additional allocations of compute quota (total 1.1MSU extra), and an additional top-up of approx 300KSU.
  • 35TB our of 100TB used of quota on /g/data/

Remember this is not intended for long-term storage, and there should always been a plan to either delete the data or move it o a long term location

3. Science talk

Christine Chung (@ctychung) (Bureau): “Projections of ENSO, IOD, and SAM change in CMIP6 models”

[ Video will be included when available ]

  • Summary of work done as part of a NESP project “Dry, Wet, Hot and Dry”, focussing on extreme wet and dry conditions.
  • Evaluating teleconnections of ENSO, IOD, SAM as main drivers of Australian seasonal rainfall variability and how they’re projected to change. Any model consensus? Is there a visible forced signal?
  • Compared CMIP5 and CMIP6. Improvement in ENSO, IOD teleconnections. Models capture asymmetry in EN?LN response and CP/EP. Simulation of SAM has improved, but teleconnection with Aus rainfall has got worse. There is a lot of internal spread among models and ensemble members. Large source of uncertainty.
  • ENSO N34 DJF. Changes in distribution, amplitude and frequency. Increase in variability and frequency.
  • El Nino internal variability twice that of La Nina. Little evidence of a forced response beyond internal variability in La Nina. Somewhat more for La Nina.
  • IOD: no clear trend in variability, or frequency, but some reduction in amplitude. Some more evidence of forced response.
  • SAM: significant shift to stronger events, but weaker in springtime. Most models show an increase in variability. Strong evidence of a forced response.
  • No consensus/consistent story.
  • Looked into concurrent events. No significant change obvious.
  • Looked into consecutive ENSO/IOD events. No forced signal obvious.

4. What’s going on?

@nicolamaher will talk at the next meeting.

@dkhutch started a forum topic to discuss what the next ESM1.5 configurations after initial ESM1.5 release.

@RachelLaw: thanks to everyone giving their feedback on the ESM1.6 scope topic.

@tiloz please contribute feedback to both topics on the forum. Plan is to complete ESM1.6 model development by the end of the year.

This is a wiki post , if you want to update any of the details in these meeting notes, or to add your own recollection of what was discussed then edit me rather than replying.