Date: Oct 7, 2025
Chair: @MartinDix
Participants: Martin
Anton
Dougie
Rachel
Romain
Spencer
Siobhan
Tilo
Chris B
Alex Norton
Aidan
Paul
Jhan
Minutes: @cbull
Martin gave an update on control run candidates ( Global ocean temperature drift · Issue #188 · ACCESS-NRI/access-esm1.6-configs · GitHub )
Tilo: would like to keep all three going. B run looks promising.
Martin: a/b/c configs only differ in the restart files.
Rachel: has a few concerns about carbon. On the land, effectively photosynthesis, seems to come in before some of the more recent changes. Something happened between the August spin up and PR-129 (Claire was doing these) – code changes that went during that period don’t seem to explain the land carbon changes. Martin: would assistance be helpful for unravelling which code changes were made? Rachel: Claire was managing this but help would be useful. Changes seem to be occurring with PFTs in the tropics (Martin: not obvious what we would have done to affect that). Currently not documented in an issue. Martin and Rachel agreed that putting some figures in an issue would be a useful next step.
On the ocean carbon side (Rachel), seem to have more of a change ? (iron deposition to blame?).
Jhan has been looking at the UM7 repository (ACCESS-NRI repo), would like to see more of the open issues resolved to be consistent with the approach taken for AM3. Martin: some of those issues are more ‘thought bubbles’ could be deferred.
Tilo: Are the emission driven forcings up to date? Could we possibly start a perturbation simulation soon-ish? Spencer: There was a PR for updating the emissions driven config. Tilo: we do need an emissions driven control as well, so would be good to parralise. Spencer: where to start? Tilo: probably at the end of the B case.
Paul:
1. Volcanic, would need to talk to spencer. Might be that the namelist wasn’t filled out to the end.
2. Still working on the ozone forcing. Qn: what is supposed to happen when it’s ready? When will it be incorporated? Martin: ozone differences look pretty small, so could likely put them in half way through a run. Paul: nitrogen is still coming.
3. The emissions driven stuff, haven’t looked at them yet. Martin: The PI-control has 0 emissions (so nothing needed there but a zero field). Martin: Actual emissions driven, haven’t looked at those fields.
Rachel: there are some idealised runs we need to set up at some point too. Namely: flat 10, 10 petagrams of carbon per year (constant) – (also: flat 10 followed by 0 emissions, flat 10 CDR reduces emissions linearly and then -10 constant petagrams of carbon per year); these 3 are part of the fast track experiments. We had a script for setting this up in esm1.5 (there’s also a set of tools at access-nri). Martin: would be good to set these up as well. Tilo: relevant past discussion here