Meeting Minutes (12/08/2025)
Present: @anton @clairecarouge @Jhan @Aidan @dhb599 @dougiesquire @manodeep @MartinDix @micael @rbeucher @spencerwong @tiloz @cbull
Arrived later: @alexnorton @harshula @micael @paulleopardi @rbeucher
Chair: @clairecarouge
Minutes: @cbull
Run crash
@Jhan had a run crash over the weekend. The crash is using the “August” version (e.g. includes CICE5, old classic compiler but have changed version). Anton, Dougie and Spencer are currently looking into it. Jhan hasn’t yet tried year 52, will try that. Spencer has found that it’s not a deterministic crash, four short runs, two of them crashed and two of them didn’t (@dougiesquire for the two that didn’t crash, are they the same? @spencerwong will check ). @MartinDix would like to look at one run that crashed and another that didn’t.
New build correctness system
@Aidan rolling out build correctness CI checks. Would like to clean up the branch names/defaults that are being used in the build here. E.g. @dougiesquire oasis3-mct can likely use the main branch, he will run a check. @anton cice5 would need a careful merge but is achievable – once this is done could use variants rather than specifying versions (@dougiesquire supports this idea and will look into it). @Aidan thinks it’s better done before production runs — not clear that it won’t change answers. @manodeep thinks it could be a good time to update oasis MCT version 5? @clairecarouge not sure if we have the bandwidth for that. @manodeep / @micael we are currently maintaining two versions of the build system to workaround some of the issues with the old system. @manodeep if it’s not answer changing then the update could be done at any time.
Australian PFTs
[@inh599 @Jhan @MartinDix @alexnorton please update this section!]
Code development to introduce the new Australian PFTs is complete (likely anyway) - final revision were implemented last week to the land-use change code - note that this change requires alterations to both the UM+CABLE codebase and the configurations as we need to also change values in some of the UM namelists irrespective of what happens inside CABLE.
Previous testing of the code - conceptually identical science configurations just with PFTs technically renumbered 2→12 and 4→13 - produced unexpected large differences. Some of this has been identified to be linked to an existing bug in the UM convection scheme (uninitialised variable) which we have opted to leave in. The rest is of equivalent magnitude to differences that arise due to internal variability - and so would be expected given the inherent numerics of reordering in the grid cell averaging routines.
At this point we ( @inh599, @Jhan and @alexnorton) believe the code+config is ready to be updated. @RachelLaw’s call as to whether to proceed. First drafts of Australian PFT parameter values (CABLE namelist and input files) and land cover maps are also ready for later testing/calibration.
Other ESM1.6 branches
@anton do we include wombat in the 4xCO2 and 1% CO2 branches? Yes but wouldn’t expect an oceanic response (@MartinDix) when WOMBAT is “uncoupled”. @tiloz previous versions of WOMBAT this was a non-issue because the tracers were handled differently. @dougiesquire thinks the new WOMBAT version will respond to the forcings but is unsure how the atmosphere will respond. Issue for 1pct BGC and RAD runs BGC and RAD coupled simulations · Issue #170 · ACCESS-NRI/access-esm1.6-configs · GitHub
Land use change
@alexnorton is it helpful to have a historical run with the land cover changes? (Aware that we’re still waiting on some of the cmip forcings.) @clairecarouge do we have the input data for that? @inh599 thinks esm1.6 amip historical could be possible but perhaps not the “full” historical period (starts in 1978). @RachelLaw is testing this currently but there is a gap in the forcing, is considering using cmip6 input forcings. @alexnorton is interested if folks think this is a worthwhile idea? @inh599 are you imagining coupled? @alexnorton yes but is constrained by what is practically possible. @inh599 would like to be clear on what the objective of doing this is. @clairecarouge configuration stability?
Other items
From @harshula : @Manodeep Sinha & @Micael Oliveira , The oneapi build workaround fix is now in the master branch of ACCESS-NRI’s oasis3-mct.