Meeting Minutes 2026: Atmosphere Working Group

Atmosphere Working Group
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Atmosphere WG meeting minutes 29/04/2026

20 participants on Zoom

Co-chairs update:

Yi Huang, Matt Woodhouse, Heidi Nettelbeck (Charmaine Franklin was an apology)

  • Yi (21st Century Weather/University of Melbourne):

    • ModSci team have build a ‘minimum working example’ for the ACCESS rAM3 suite. Hard coded a single domain driven by ECMWF with simplified cylc logic and configuration files. Primary use was to help develop the centre’s regional coupled model, but it could also be used to support tutorials and training materials for NRI.
    • ModSci team is also engaging NRI and BoM to work on netCDF conversion of AM3/rAM3.
    • AM3 team has been testing N512 (~25 km) runs which will support AM3-beta release. Testing is underway using N96 ancillaries reconfigured to N512.
    • Seeking feedback for ENSO experiments using this model
    • rCM3 work is going well.
    • Contact Julie Arblaster (lead CI for ModSci team) and Shixue Li for AM3

  • Matt (CSIRO) :

    • Still working through the CSIRO restructure which is unsettling for everyone. :sad_but_relieved_face: :raised_fist:
    • ESM1.6 simulations for CMIP7 are underway.

  • Heidi (ACCESS-NRI):

Co-chair shake-up!

  • Matt and Charmaine are standing down. Welcome to Sonya Fiddes and Andrew Brown in their new roles! :partying_face: :confetti_ball:
  • Yi will still co-chair the WG to manage transition to new co-chairs.

Steve Sherwood proposal:

  • Steve Sherwood wants to run high-resolution simulations to support machine learning into small scale atmospheric interactions. We need high temporal resolution to train a hybrid ML models. We are hoping to run a suite to run and do model training ‘on-the-fly’ on data with very high temporal and spatial resolutions. Can we start talking about this before the August meeting. If you’re interested, have comments, or share experiences on what is currently underway, please share?(Steve took a shapshot of people raising hands showing interest)

Claire Courage and Chermelle Engel - plans for AM3/rAM3

  • FYI Chermelle is now in land team as she’s working on coupling rAM3 with CABLE
  • Claire : AM3 plans
    • Beta release. Single atm and land source code for ACCESS3
    • Upgrade to cylc8, Using UMv13.8
    • Use CCI ancillaries (hopefully!)
    • Support for N96 and N512 resolutions (with help from 21st Century Weather)
    • Publish documentation
    • Training videos and possible a training event
    • Science features in the future
      • Update ancillaries to CMIP7 dataset to support recent time periods
      • Support Australian tree PFTs (?) land cover and parameters for these types
      • Activate biochemistry
      • Working on biogenic emissions and some depositions
      • Urban model (hopefully) dependent on extra NRI funding
      • Extra configurations?
    • Evaluation
      • Gathering atmospheric recipes. At the moment we only evaluate atmospheric / water balance
      • AM3 - ILAMB (land-based evaluation) workflow
      • Rapid Evaluation Framework
  • CABLE coupling in CM3 and rAM3
    • River routing
    • Evaluation
  • Optimisation
    • Some profiling
    • Full optimisation not in this Financial Year
  • Claire showed a schematic workflow. The ultimate aim is to make AM3 and rAM3 (and ultimately CM3) a common code base using same ancillary suites

Q : Julie Arblaster re: consistency b/w AM3 and CM3. If you did an AMIP run with AM3, that will be different to atmosphere CMIP?
A : Claire - will depend on the release schedule. When we get to UMv13.8 and when we incorporate biochemistry.

  • Chermelle : rAM3plans
    • Science features
      • UM v13.8
      • CABLE land surface model
      • Generalised GRIB paths for BARRA and CMIP driving models
      • Support for longer-running regional climate runs (including monthly-varying aerosol ancils)
      • Adopting GLOMAP/CASIM to support chemistry community (stretch goal)
    • Technical support
    • Working with BoM/21st Century Weather on netCDF post-processing options

Q : Sonya re: chemistry?
A : Chermelle - the existing UM partnership regional climate suite has its own workflows for dealing with aerosols. NRI have decided not to support another suite, rather will add this functionality (after discussions with UKMO) to the existing (and better supported) RNS suite.
A : Matt - running these configs requires adding aerosol fields to start dumps. Myself and Sonya have a lot of experience with thus
Q: Julie re: urban ancillary funding?
A : Claire. Waiting on NCRIS decision. This will determine what we support.
Q : Paul Leopardi : Longer term CMIP7 campaign depends on CSIRO, not NRI AM planning?
A : Claire : NRI is also waiting for funding announcements.

Ashley Barnes - rCM3 updates

  • First run of a ‘Frankenmodel’. Created by
    • Using rAM3 to define a domain, ancils, namelists and ICs and LBCs
    • Using rOM3 to do the same. Currently a small test domain centred around Lismore
    • Latest CM3 config. Update UM version from 13.0 → 13.5. Remove ICE and other problems associated with global configurations (e.g. global river runoffs)
    • Have to activate c_tiles in rAM3 namelists to allow fractional land.
    • Mash them all together
    • Currently have two frankenmodels, one for GAL9 (global model) and one for RAL3 (hi-res convection permitting resolutions)
    • Currently running outside of rose-cylc, which removes some of the obsfucation that rose can perform in generating namelists
    • We can start thinking about preliminary science runs. But workflow is still fully manual.
  • Next steps
    • Some bug fixes and issues with RAL3 precipitation
    • Set up some science runs and validate
    • Create an automated workflow
    • Reconcile rCM3 and CM3 source. We think we can share a common executable for both models in the future
    • Source code. Need to handle ice and run-off smoothing with if statements. Mainly related to NUOPCY cap. Kieran has already started doing this for OM3 work.
    • Changing to read mesh from disk, rather than creating the mesh in memory
    • Using total precip rather than resolved + convective in the coupling mediator
    • Do we wait for Spack build for CM3 and move to UMv13.8 or do a big push now and have two branches that use different UM versions?
  • Necessary fixes
    • Surface stresses are currently zero. May be related to removing ICE
    • Have to figure out restarts
    • Should we use rAM3 patches rather than using vanilla UMv13.5?
    • Ideally - use netCDF outputs
    • Check land/sea mask behaviour
    • Turn off river run-of
  • Early science and validation runs : Andrew Brown - sea breezes, Madi Rosevear - ocean fluxes
  • Automation pipeline
    • We can use rAM3 rose/cylc minimum working example for a single-nest run
    • Keen to build a python notebook which can test and modify ancillaries (e.g. vegetation, forcing and bathymetry) and view them in a single package
    • Hope to have single-nested science runs completed by late 2026.

Heidi : resource update

  • We have 2MSU available this quarter. No applications yet! Please apply in the usual way.
  • Do we want to switch timeslots from 11:30?