Meeting minutes
Date: 08/04/2025
Attendees: Romain, Claire, Harshula, Martin, Tilo, Michael, Manodeep, Jhan, Dougie, Dave, Aidan, Ian, Lachlan, Spencer, Pearse, Paul
Cascade Lake non-reproducibility
Manodeep: Configs now run on SapphireRapids (~20% faster). PI runs non-reproducible on CascadeLake cores when changing atmosphere layout. With the same ocean layout but different atmosphere layout. AMIP runs with any atmosphere layout are deterministic.
Micael and Martin agree it is not worth chasing further but important to document.
New WOMBAT-lite
@dougiesquire and @pearseb have released a new version of WOMBAT-lite on main. Can there be a new ESM1.6 build release using that update? It is almost identical to what Pearse has used in the spin up run. @dougiesquire cmake build stuff is still not in main, so could either release from dev tag or try to get that in. @Aidan the latter would be better. @harshula to organise doing this asap.
It has also implications for the new spin up configuration we want to put in place. The ocean restart will need some manual change in the deep ocean for the ocean BGC to use the new WOMBAT-lite. (@pearseb to do).
When do we want to start the new spin up? @tiloz does not want to wait too much as there are more changes coming. It might be good to start before Easter so we can analyse and fix some problems before it runs through Easter time.
Decision: we shouldn’t wait too long to the new WOMBAT-lite. If it can come in today or about, it can go in the new spin up. Otherwise, it will get integrated later on.
Spin ups and tests
@tiloz says Pearse’s current spin up can still run in parallel to the new spin up so Pearse can test changes in the ocean, sea ice and BGC. Same approach to be used if we have new changes focused on the land later on.
Salinity decrease
@dhb599 Salinity decrease, have tests been done with a parameter change to solve this? @pearseb Dave’s suggestion seems to solve the decreasing salinity. @inh599 says we may want to undo that because new land changes that are coming in are slightly increasing the salinity. The parameter is a tunable parameter so can be modified depending on what an experiment produces.
CICE5 technically working
@dhb599 says CICE5 is now working technically in ESM1.5. Haven’t checked results yet. @anton and Siobhan need to analyse it.