CSIRO - ACCESS-NRI standup minutes

CMIP7 CMIP7 development
41

Meeting minutes (24/06/2025)

@clairecarouge
@inh599
@Jhan
@Aidan
@anton
@dougiesquire
@ezhilsabareesh8
@manodeep
@micael
@paulleopardi
@RachelLaw
@spencerwong
@cbull
Chair: @clairecarouge
Minutes: @cbull

MOM5 and cmake

  • Updating to MOM5 build with CMake (some context here). There is also updating the grid.
  • Rachel: happy for changes to go in given we don’t expect any radical answer changes.
  • Aidan (speaking for Harshula): does this affect generic tracers? Dougie: Currently, we are building from the development branch that Harshula has been looking into.
  • Ian: are there any downstream impacts on the model? Land sea-mask changes? Dougie: Land sea-mask has not changed. Re-gridding weights have been changed a little.
  • Claire: also supports bundling them together.
  • Anton: was hoping to do the build and CICE5 changes at the same time. Are there other build changes planned for UM / Cable? Ian/Rachel: Yes, they are coming but they are a while away.
  • Rachel: is it worth doing a 4xCO2 run in CICE5? Anton: is there a configuration already running with CICE4? Rachel noted that there is a config on GitHub but it doesn’t appear to be up to date with the spin-up configuration so Tilo had taken the dev-preindustrial+concentrations config and made the one line change required (changing CO2MMR value in line 652 in atmosphere/namelists). There is also some documentation in this forum post
  • Ian: slight backtrack. Would be good to separate technical and science changes.
  • @paulleopardi I missed your comment please add.
  • @dougiesquire suggested some changes are ready now but others such as the grid change (relevant to the med’ salinity issue) are blocked, would be at least a week for that one

Updates on oneAPI compiler switch

See details in a table at the top comment in this PR

With the new compiler the atmosphere is now “faster” than the ocean (was the opposite using the old compiler), this has led to a different load balancing with the new compiler. (Micael clarified that MOM5 is actually just slower so the atmosphere is unchanged.) Manodeep is going to look into whether giving the ocean more cores will improve performance, this will break bitwise repro’ so he’s been delaying this test. Manodeep wanted to know if it was possible that we use the old compiler for spin up and then when we go to production with the new compiler. Yes, that is a possible solution. @RachelLaw (@inh599 agreed) suggested having ~100 years of the new one before going to production. @micael wished to emphasise the the old compiler will stop getting improvements but in theory the new compiler should be capable of the same performance and so will hopefully “get it” in the future (@cbull and @micael note that this change down the line could be answer changing.)

Decisions Made

  • Proceed with infrastructure changes as they become ready, rather than waiting to bundle them. Separate technical and science updates where possible.
  • Keep the spin-up configuration updated and documented on the forum.
  • Avoid bundling too many changes at once to simplify debugging.
  • Maintain flexibility in compiler use during spin-up, but aim to finalize before production.
  • Accept that some answer changes may be inevitable with future compiler/machine updates.

Action Items

  • Dougie to proceed with MOM5 and CMake updates when ready.
  • Keep the spin-up configuration table updated on the forum.
  • Rachel (?) to locate and share the forum post documenting the 4xCO₂ runs. - this is already linked in the comment above. I’ve added some extra detail around the config status.
  • Manodeep to continue performance testing with oneAPI and explore optimal configurations.
42

Meeting minutes (01/07/2025)

Participants:
@anton
@manodeep
@clairecarouge
@paulleopardi
@MartinDix
@inh599
@pearseb
@Aidan
@adfraser
@dhb599
@dougiesquire
@harshula
@manodeep
@RachelLaw
@tiloz
@cbull

Chair: @clairecarouge
Minutes: @cbull

Action items from last week.

Rachel last week suggesting running 4xCO2 CICE5. Anton has done a run and will make some plots and put them on GitHub.

Next steps: Tilo configuration still needs to be finalised. Martin: encountered some Payu issues that are being worked through. Once they are sorted he will share the configuration [@MartinDix there were a few configurations here I think?]

Manodeep clarified: so everything else except the 4xCO2 is using CICE4. Anton: everything (all configurations) will be rolled over to CICE5 once we are happy with using CICE5.

@Paul: FYI will need details of configurations running and planned, to update the CMIP7 ACCESS-ESM1.6 ancillary suite and Python scripts. See https://code.metoffice.gov.uk/trac/roses-u/ticket/648 and Produce ancillaries for ACCESS-ESM1.6 submission to CMIP7 · Issue #23 · ACCESS-NRI/CMIP7-Input · GitHub

@spencerwong has been looking into freshwater spreading options. Looks like there’s some curiosities with conservation. Spencer is currently putting together what he’s found in an issue. @inh599: has looked into this in the past and is open to discussing further.

@inh599 update: have been working on Australian PFTs.

@manodeep update on the oneapi transition. Recap oneapi performance was 20-25% worse last week. Has tried adding a node and that leads to the same performance as before (with a higher SU cost).

@RachelLaw: @tiloz has flagged that there is 0 allocation on p66 for compute. We may need to ask other people for some resources.

43

Meeting minutes (08/07/2025)

Participants:
@cbull
@anton
@Aidan
@MartinDix
@pearseb
@alexnorton
@clairecarouge
@dhb599
@dougiesquire
@harshula
@inh599
@jemmajeffree
@manodeep
@paulleopardi
@RachelLaw
@rbeucher
@spencerwong
@tiloz
Chair: @clairecarouge
Minutes: @cbull

Manodeep optimisation update
oneapi with a new version is now matching classic compiler performance
19.6 vs 19.1 years per wall day. See PR for details

Manodeep is also looking into optimisation in terms of layout changes but this will break reproducibility. Martin: would entertain it if the performance was worthwhile so would be good to profile (as long as it doesn’t break determinism).

Aidan on metadata standards. Clare, Kelsey, Aidan, Martin, Romain have been working on an output specification document that describes all the ESM1.6 output. Aidan has been leading the global attributes spec’ where the plan is for this information to be injected into the file outputs by Payu using Axiom (e.g. model, model version, uuid etc). Aidan can share the doc via Sharepoint (needs an invite). Jemma suggestion: “I think it’s valuable to keep stuff that’s in the filename also in the metadata, just because it’s harder to accidentally rename the metadata.”

Claire: thinking behind netcdf version, is it for compression? Aidan: No there’s a few things, Netcdf 4 classic has a smaller subset of Netcdf 4 and is backwards compatible – however, compression is worthwhile. Anton: can turn on compression for cice (not sure of effort or timeline) but it’s part of a wider plan.

Ian: land (cable + mosis) via the UM makes things a little complicated so needs to be described more carefully (can take the discussion offline, Dougie is interested too). Rachel: is there any synergy here between cmor and the existing outputs? Romain: some but this process helps facilitate cmor-isation.

Spencer and Martin have found an old bug in the inland basin code for river (runoff?) which they are investigating.

Wouldn’t it be simpler just to assign salinity from the surface to every depth level in the Mediterranean? and run a control & new config from there?

Mediterranean sea (this discussion was also continued after the stand up with @MartinDix, @RachelLaw, @pearseb, @inh599, @cbull, @dougiesquire)
@ezhilsabareesh8 is leaving ACCESS-NRI so progress on this has been disrupted, see Ezhil’s summary. @cbull has been looking into it and was interested in what @inh599 and others had already looked at (sea surface salinity mostly). Rachel suggested ping’ing @matthew.chamberlain on the GH issue for the latest set of plots he’s made. The discussion converged on trialling bigger bathymetry changes (or aphysical mixing as @dhb599 proposed) and re-setting the whole med’ sea salinity back to initial conditions. Concern that the excess salinity in the western salinity may flow out into the Atlantic and affect the AMOC (we should try and avoid this) although a signature of western med salinity is visible in the Atlantic in the i.c. files.

Both @clairecarouge and @cbull can’t attend next week. Martin and Spencer can run next week (chair/minutes resp’)

44

Meeting minutes (15/07/2025)

Participants:
@MartinDix
@Aidan
@anton
@spencerwong
@manodeep
@paulleopardi
@RachelLaw
@rbeucher
@tiloz
@alexnorton
@jemmajeffree
@dougiesquire
@dhb599
@inh599
@harshula

CICE5:

@anton has run ~130 years of a 4xCO2 run with a CICE5 config. Results for SAT and TOA radiation are nearly identical compared to the AprilSpinup 4XCO2 run. Climate sensitivity is ~3.357 K for the AprilSpinup configuration and 3.290 K for the CICE5 run, and the difference is possibly within sampling noise.

Unclear on when to make the swap to CICE5. Masking changes will require a change to add_lprec, however potential updates to the UM will change this again. Should the swap be done at the same time as the UM changes and the change to oneAPI?

@Aidan in favour of swapping to CICE5 sooner rather than later, as it reduces the problem space.

OneAPI

@manodeep: The oneAPI has reached performance parity with the classic compilers. Results are not bit for bit identical, which is to be expected. We are now ready to do long runs to evaluate the science impacts of the change.

Cable: Australian PFTs

@inh599 has met with the Hawkesbury Institute at UWS who will be helping with parameter values. Some work is needed on this.

On the code side, @Jhan has found that runs which shuffle the indexes and should be bitwise identical are not. This seems to trigger differences in random places such as over the ocean, even though the code changes should only effect land.

@MartinDix to follow up with @Jhan, and suggests a memory overwrite could be happening somewhere.

Ambition is to finalise the Australian PFT work before the proper control run.

@RachelLaw: Aside from the Australian PFTs, we also want to change the vegetation distribution. @alexnorton is working on this. Additionally, there are problems in the CO2 seasonality especially at high latitudes, suggesting problems with leaf respiration that need to be chased down.

Cable: Library

@inh599 notes that work on cable as a library is still ongoing. @lachlanswhyborn is investigating bit reproducibility problems. Simultaneous developments on Cable main make it complicated to coordinate this work.

1pct CO2 configuration

A 1pct CO2 configuration is now available here, which @tiloz is testing. Temperature and CO2 are going up as expected.

It would be useful to add a convenient way of checking the gas concentrations that the model actually sees. Currently it’s difficult to confirm whether config changes are being picked up by the model.

Ancillary generation

@paulleopardi will set up a new branch on the ESM1.6 configs repository to test out generating forcings for the Historical configuration.

CMIP7 data request

@rbeucher has read through the CMIP7 data request and produced a spreadsheet of the requested variables, and their current status in ESM1.6. Please look over the spreadsheet (linked here )and add comments.

Fast track timeline

@Tilo notes that the fast track deadline is end of 2026. As we have a relatively fast model, and various configurations in runnable states, that allows us some more time to finalise the code. However we don’t want to drag it out for too long.

NetCDF conversion failures

netCDF conversion failures have been encountered by everyone running the model. @jo-basevi is investigating the causes and will submit an nci help request. @spencerwong has started a forum topic here to collect reports of the failures. Please add a comment with details of any failures you encounter. Reports close to the time of the crash would be especially useful.

45

Meeting minutes (22/07/2025)

Participants:
@anton
@lachlanswhyborn
@inh599
@MartinDix
@Jhan
@pearseb
@Aidan
@adfraser
@dhb599
@harshula
@jemmajeffree
@manodeep
@paulleopardi
@RachelLaw
@rbeucher
@tiloz
@cbull
@clairecarouge

Chair: @clairecarouge
Minutes: @cbull

payu dev bug

Spencer added things to calendar handling for the UM in esm1.6 late last week in Payu. This unfortunately broke running new experiments with Payu (existing submitted runs should have been okay), but was fixed yesterday and new payu dev should be working again.

water conservation in the um

Ian, Spencer and Martin have been looking into water conservation issue in the UM. Unravelling compensating errors. Could be a substantive bit of work to fix all the bugs. Considering rolling back to an earlier version. Jhan asked for further detail. CICE4 is doing a better job (Martin it’s not actually a CICE issue but the issue was found through the model change). Martin: Atmosphere is creating water, which could be balanced with scaling the river outflow (by a few %). Ian had a look at this and thinks it goes through about 14 layers of code. Martin: Could a module be used? Spencer has been looking into it. Martin is keen to keep looking into how feasible is it.

Lachlan doing some tests with some compiler flags off

Lachlan: ESM1.6 with CABLE included as a library within UM7, rather than as source code, bitwise reproduces the release build when optimisations are turned off i.e. release compiled with -O0 is identical to library build with -O0. Doing a 10 year run with optimisations turned back on with -O2, and comparing results to determine effect of optimisations on behaviour. First few years suggest runtime/year is about the same between builds, perhaps even slightly faster with the library, but most likely just natural variance.

Australian PFTs

Ian: Martin and Jhan are still looking into Australian PFTs.

Radiation frequency

Martin: Using hourly radiation (rather than 3 hourly) gives a better land surface energy balance but also has a larger effect on net surface SW than expected (even seems to affect something as basic as amount of Rayleigh scattering). Likely to have an unacceptably large effect on the overall surface energy budget. Ian and Martin think it needs to be parked.

Forcing update

Martin: no update on the forcing but still waiting on the ozone. Paul hasn’t seen it yet (July is a possibility).

Optimisation

Manodeep: 20 model years per day using 4 nodes per day (1000 Su). 5 nodes can get us up to 22 model years per day (1200 Su). Anton: is it harder to justify on a NCIMASS type application, Manodeep highlighted that he has tested 1-4 nodes as well and they all are more mpi efficient so there’s a balance. Tilo: 1kSu 20 years/d is similar to esm1.5 and would be happy with that (for production runs). Aidan: are you resource or time constrained? Tilo: both and storage. Martin would like to see both configs available. Aidan: highlighted current tests are using cice4 would be good to confirm that cice5 has similar performance. Rachel: we are generally limited by our ability to post-process, quality control and assess simulations.

General updates?

None.

46

Meeting minutes (29/07/2025)

Participants:
@cbull
@clairecarouge
@anton
@lachlanswhyborn
@dhb599
@inh599
@dougiesquire
@jemmajeffree
@manodeep
@paulleopardi
@RachelLaw
@rbeucher
@tiloz
@micael
@spencerwong
@tiloz
@Jhan
@Aidan
@alexnorton

Chair: @clairecarouge
Minutes: @cbull

The day’s standup consisted of discussing revisions and updates to the implementation of development threads for the upcoming configuration/build freeze so that the final spin up can be done. During the meeting a live editable version of the table from Coordinating development threads for next phase of control experiment was edited.

Following the meeting @cbull and @clairecarouge revised the table, re-ordering in terms of sequencing and priority. The new table is posted here.

47

Meeting minutes (5/08/2025)

Participants:
@cbull
@clairecarouge

@micael
@anton
@inh599

@jemmajeffree

@manodeep

@paulleopardi
@RachelLaw
@rbeucher

@tiloz
@spencerwong
@tiloz
@Jhan
@alexnorton

@pearseb

@Aidan

Chair: @clairecarouge
Minutes: @cbull

Project Coordination and Workflow

  • Claire gave an overview of the proposed forward protocol for folding in everyone’s development threads. @jhan is confirmed as the runner for integrating changes.
  • Claire emphasized the importance of coordination between contributors, runners, and reviewers.

Experiment Management

  • Discussion on whether to start new experiments or continue existing ones when applying changes.
    • Anton and Chris highlighted the need for new experiments when restart files are modified.
    • Ian stressed the importance of maintaining an accurate spin-up table for tracking changes.
    • Mixed approaches have been used so far; flexibility remains depending on the nature of changes.

Status Updates

  • Anton: Order 1 items are ready to go; Anton confirmed a 50-year test was run over the weekend (to decide on lprec value).
    • @anton and @Jhan will have an offline meeting to coordinate getting all the order 1 items going.
  • Ian raised concerns about long-term cooling trends in the deep ocean.
    • Pearse suggested Antarctic Bottom Water dynamics may be contributing.
    • Tilo and Rachel discussed whether this is a spin-up issue or a deeper energy imbalance.
    • Further investigation is needed, but changes to sea ice and vegetation may help.
  • Ian: still trying to understand the long-term change in temperature. We’re nearly at 2000 years and for the last 500 years the deep ocean has been cooling. Pearse: Matt and Pearse think that the AABW upwelling is affecting tracers at mid-latitudes. This may have been driven by the changes we made in southern ocean fluxes (change of distribution of fresh water has changed southern ocean overturning). Pearse is wondering if we need even more spin up time for this problem might resolve itself? Tilo: thinks Ian is concerned that there is an energy imbalance issue not a spin up issue. Rachel: thinks CICE5 coming in is a priority and need to see what impact that has. Rachel has suggested if Ian thinks energy imbalance could be canopy related then latest veg distribution has some reduction in trees. Pearse views the impact on the BGC and global ocean metrics as minor.
  • Paul: still waiting on the ozone and nitrogen forcings. Current guidance is that it was due in July and they are still running simulations. See link.
  • Spencer: wanted to check if anyone had any follow up thoughts on the water balance issue. Do we want to try some of the UM changes or stick with what we have now? Ian: would be interested to see how the salinity is affected by the changes? But in general, would like to see the changes go in. Spencer: has done a 50 year run but didn’t see any major changes so will consider running it a bit longer.
  • Vegetation and Australian PFT updates are progressing.
    • Alex confirmed restart creation; awaiting system availability.

Scheduling and Prioritization

  • Chris Bull suggested swapping Spencer and Alex’s items with Manodeep’s if needed.
    • Manodeep noted oneAPI changes need a week of testing.
    • Decision: maintain current order but allow flexibility based on readiness.

Technical and CI Updates

  • Harshula asked for any Spack issues; none raised.
  • Ian reported no conversion failures in recent runs. Aidan commented that nothing has changed infrastructure wise during that time.
48

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.

49

Meeting Minutes (19/08/2025)

Present: @clairecarouge, @spencerwong, @manodeep, @paulleopardi, @dougiesquire, @RachelLaw, @harshula, @jemmajeffree, @Aidan, @MartinDix, @rbeucher, @inh599, @anton, @pearseb, @sofarrell, @dhb599, @alexnorton

Chair: @clairecarouge
Minutes: @spencerwong

New experiment runner
As @Jhan will be on leave for a couple of weeks, it was decided to try and find someone to cover as the experiment runner, especially in light of the recent random crashes. @tiloz, @clairecarouge, and @RachelLaw will discuss further to find someone.

Wombat crashes
Random wombat crashes have been occurring at the start of simulations. @pearseb has looked into it. The crashes always occur at a particular routine, though there’s no indications of problems in the MOM restart data.

@MartinDix suggests that there could be something not being read correctly, and @manodeep mentions that there could be a race condition. @dhb599 has also had this error during test runs. Usually it resolves upon restarting, however in one case, restarting repeatedly reproduces the error. @dougiesquire will investigate more over the next few days. @spencerwong will test whether oneAPI has any effect.

Australian PFTs
@RachelLaw and @alexnorton are running several AMIP runs to test different parameterisations for the Australian PFTs. So far, these do not appear to cause major differences, and the changes in carbon fluxes are within the range of variability. More tests are being run to make sure that various metrics look sensible. LUC is also working.

Ocean temperature drift
@tiloz mentions that the priority should be on understanding the ocean temperature drift before bringing in further configuration changes, especially as the drift has increased when changing to CICE5.

@MartinDix is testing ocean albedo changes, and has done additional tests with the AprilSpinup configuration. Using the AprilSpinup configuration but removing the solar constant change results in a short drop in ocean temperature, but does not show any large long term drift.

@spencerwong will look into the proposed water balance changes. They will alter the global runoff, and hence will likely impact the iceberg melt.

Infrastructure changes
@Aidan notes that there are infrastructure changes ready to be made to the ESM1.6 model deployment repository, however it makes sense to wait until development is less active to make these changes, as they will require rebasing each open PR. We should let @Aidan know when it’s a good time to make these changes.

50

Meeting Minutes (26/08/2025)

Participants: @clairecarouge , @cbull , @RachelLaw @spencerwong @MartinDix , @manodeep , @tiloz , @Aidan ,@alexnorton, @harshula, @inh599, @jemmajeffree, @micael, @rbeucher, @sofarrell

Chair: @clairecarouge

Minutes: @cbull

Recent crashes

@spencerwong Testing different versions of mpi and compiler. Seems some versions of openmpi / wombat stop the crashes. @dougiesquire/@pearseb is looking into it further.

CICE crash, @spencerwong was talking to someone at NCI, upgrading openmpi helped there too. From crashes 1/100 to 1/700 years.

@dougiesquire suggestion: oneapi and openmpi 5 that we go that way as soon as possible (the wombat issue can be further investigated on the side). @manodeep is currently testing this combination / optimising.

Action: @manodeep will put the related PRs together.

Changing compiler flags is currently difficult

@paulleopardi , @lachlanswhyborn, @harshula has been asking about the Spack build. Current spack build does not allow one to change compiler flags for components that use the FCM build system (UM7 and GCOM) on the fly. Doing some scoping work to see if this can be modified. @lachlanswhyborn clarification: spack.yaml does in theory allow one to specify flags, however UM will silently ignore all these flags or architecture flags.

Ocean drift issue

@tiloz : discussion with many people on Friday. There were two options and one lesson that came out:

  • change parameters that influence freshwater fluxes in the polar regions but likely quite a limited impact;
  • change ocean albedo.
  • @RachelLaw lesson learned: we now understand why CICE5 rather than CICE4 has significant changes in ocean cooling, related to value of aicenmin(default is 1e-11) but we think we need something close to what it is now in CICE5 (2e-4) same as on UM7.3 side of code @sofarrell.

@MartinDix : update on changing ocean albedo (tweaked to cancel out solar constant changes – reduction in 4% of absolute value), from the start of the “June spin up”. Looks like it helped but not enough. Considering trying the same parameter change from the start of the “April spin up” (when the solar constant change was done @sofarrell ).

Large temporary output file from proc 207

Found when @RachelLaw and @inh599 were discussing a crash. Work output in processor 207 (the proc responsible for the rivers). @inh599 is logging saying that outputs are “not positive”. Possibly related to how values have been changed in inland water basins. One solution could be suppress the warning (the solutions are ok). @MartinDix : is it happening everywhere? @inh599 unsure, comes out in the work temp dir. @spencerwong: there is an upcoming change that will resolve this issue.

OASIS3MCT

Last week we talked about getting rid of esm1.5/esm1.6 branches in the build. Currently, we are using the esm1.5 branch for oasis. @dougiesquire did a test with the master branch and it’s bitwise reproducible. Note compiler flags will likely change when we start using the same branch across both models.

@manodeep: Upstream is version 5, currently we are using version 2. Quite a few years in between the two versions. In version 5, load balancing logging output is a welcome improvement and would help the optimisation work (better load balance).

@dougiesquire would ask that we do the upgrade in two steps: 1. switch to main branch, then do upstream update.

No objections from the room on these proposed changes.

Misc

  • @RachelLaw has updated the table to capture all the planned land updates and is looking to pull them together, a little difficult as @Jhan is on leave. @clairecarouge is happy to help with the build side of things. Related issue.
  • @paulleopardi forcings for ozone and nitrogen are now available. Stilll missing documentation on what’s inside them. Pending issue: files on Gadi are out of date and Paul needs a Gadi software update to get newer versions.
  • @RachelLaw : would be good to do a historical test (with CMIP6 forcing) since land-use change file now ready. @MartinDix is happy to set up configuration.