Technical Working Group Meeting, April 2017


Date: 11th April 2017

  • Marshall Ward (NCI, Chair)
  • Aidan Heerdegen (ARCCSS)
  • Nicholas Hannah (ARCCSS/Double Precision)
  • Russ Fiedler and Matt Chamberlain (CSIRO Hobart)
  • Justin Freeman and Mirko Velic (BoM)

Updates on previous actions

  • Nic has transferred MOM code repos to a new organisation MOM-ocean
  • Official MOM website URL is now
  • MOM5 input files have been moved to a new location, administered by Paola Petrelli (ARCCSS CMS team) Licensing has been confirmed as GPL by Stephen Griffies.

    COSIMA Workshop

    • Agreement that we want to present some summary of the work of the TWG to date. Important to show what we’ve done: Model sharing, Grid sharing, Important infrastructure activities.
    • Discussion around what to put cover in the presentation: What are the most important projects? What is most interesting? What do we want to work on?
    • Some ideas for important topics:
      1. Coherent sharing of experiments with others, as is possible with Rose/cylc
      2. Performance is always important, can motivate others to support our work
      3. Coherence around OASIS.
    • Nic will present a 1/10th coupled model update and results. Should have something decent by then
    • Need to raise issue of the coupler, present some options and get some feedback from the stakeholders. Justin is concerned about wave coupling in future. Inform wider group about what we’re thinking. Judge appetite for changing tools.
    • OASIS is not well liked, is difficult to use and performs poorly.
    • If someone has concerns about the coupler/MATM then we need to back that up with numbers. Marshall will start a new google discussion doc for this
    • Marshall has CM2 numbers that are difficult to understand. Probably not worth presenting to COSIMA
    • Aidan not presenting at present. Russ might talk about grid stuff. Matt might talk about some of the technical aspects of 0.25 deg run. Maybe parameterisation of bulk formulas.
    • There was a general feeling the TWG was functioning well and no significant change required. Matt suggested a face to face meet-up might be worthwhile. Mirko pointed out we need some metrics to show to others that TWG is a worthwhile venture and why we’re so pleased with ourselves


    • Nic has had 3 week break. Visited GFDL. Presented his coupler at a coupling workshop. Talked to OASIS, MCT, ESMF and YAC (Yet Another Coupler). ESMF are building 2nd order conservative support into their remapping weight software which is good for us.
    • Matt: has been working with GFDL coupled model for Terry O’Kane. Using ACCESS 1 deg grid in CM2 with AM2 atmosphere. Several 100 years. Decadal forecasting. Atmosphere is same as CM2.1. Maybe 2.5 deg. Would be nice to have higher resolution, but for forecasting need ensembles. 10-40 ensembles. UM is too slow for this sort of work. There is some innterest in benchmarking for ocean structure, maybe against CM3. Maybe the go to 0.25 ocean, AM3 atmosphere model. Then put through data assimilation system. Then put in forecast mode. Look for predictive skill.

    COSIMA Models

    • Not made much progress on ACCESS-OM2-01. Technically coupled. Now trying to speed it up for multi-year runs. Currently running 600s timestep. Still in January.
    • Not currently JRA55 forced. Can’t talk about tenth ACCESS-OM2 performance yet.
    • CICE has some shocks on spin-up. Was aiming for 600s, but the current operational time step is 450s. Pulling back to 450s will be a lot easier. Goal to make 600s the prroduction time step. Russ can sometimes run 720s or even 900s for this tenth simulation.
    • Matt pointed out it is difficult to start a simulation with CICE when initial conditions have no sea ice. Better to create initial conditions from World Ocean Atlas.
    • Matt is now running COREII IAF. Sometimes blows up, just drops time step for a month, and if no issue, doesn’t try to diagnose problem, just goes back to normal time step. Matt is running 600s with a tenth MOM/SIS.
    • Aidan talked about issues with the current ACCESS-OM2-025+JRA55, discovered the scripts for MOM5 are not using the same OASIS build as the other components. Trying to work out why the model is running so slowly.



    • Start a new google doc about coupler issues and MATM (Marshall)


    • Nic to present MATM code re-write proposal to TWG for feedback before sign-off. Will then be presented to Andy Hogg for approval.
    • Add Peter’s CICE5.1 config to OceansAus github repo (Nic and Peter)
    • Port MOM5 build system to cmake (Aidan)
    • Push updated MATM code with JRA-55 support to OceansAus github (Aidan)
    • Nic create a discussion document (on COSIMA?) to document current approaches and strategies for future
    • Move FMS to submodule of MOM5 github repo (Marshall). Liase with Nic on implementation?
    • Test Nic’s access-om model config on OceansAus (All)
    • Work up test cases to cover the nudging code (Justin, Mirko) and supply them to Nic.
    • Move to CICE5 on OceansAus repo (Nic).
    • Add new test cases to Jenkins test suite (Nic).