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… by ice concentration before coupling (unscale in UM)
…oming fluxes by ice fraction
…m in the cap from local fluxes (#11) Co-authored-by: Kieran Ricardo <kieran.ricardo@anu.edu.au>
* Add meltponds to ice export * Scale pond fraction and depths to conserve area and volume * Abort if tr_pond_lvl selected
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Merge conflicts while updating CICE driversWe had no conflicts in the core CICE code. I rebased our Several conflicts came up in the merge. I'll record each of the conflicts here for the purpose of documentation. For review, I've separated them into more substantial conflicts, and much more straightforward ones where I'm more confident in my choice for resolution. Where relevant, I've tried to include some background on the upstream or local changes that caused the conflicts. The Changes more likely to need reviewNew
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kieranricardo
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Apr 23, 2025
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Great work @blimlim!!
- I suspect the water balance error increase is unrelated to your changes, and probably caused by TTI/coupling time stepping changes. Either way I think the increase is negligible, but I'll check whether it's caused by the time offset
- the salt flux errors look fine to me, the absolute values are so small that I think you're right that the time step offset is causing this
- swapping to the CESM names seems like the right approach to me, it's more readable and consistent with main
- keeping the aerosols seems reasonable
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Not to be merged
This PR describes the changes made when updating the CICE version used by CM3 from 8e2aab2 to 2025.01.0, the version used in OM3 0.4.0. If the changes are approved, I'll change the branch name from
cm3-update-cicetocm3-coupling-0.4.0(or another name if we decide on a different naming scheme).This branch was created by rebasing
cm3-couplingonto e68e05b (i.e. 2025.01.0). This update should be done in parallel to the icepack update at ACCESS-NRI/Icepack#7.Water balance
The following plots compare the water balance before any of the version updates (i.e. before any of the MOM, CMEPS, CICE updates), and after the latest CICE and ICEPACK updates. (I accidentally deleted my intermediate run which had the MOM+CMEPS changes, but not the CICE+ICEPACK uptdates). Note that there were other changes to the suite including the swap to the time travelling ice scheme between these two simulations.
The water balance looks quite similar. By the end of the year, the updated code does show a bigger change in equivalent sea level: ~ 0.00075873 m difference:
Fluxes:
The following show the errors in the fluxes for each of the two runs:
Water balance
Details
The water flux errors are very comparable between the two runs.
Energy balance
Details
Energy flux errors also are comparable.
Ice to ocean fluxes
Details
Here is the main cause for concern: the relative error for the ice-ocean salt flux increased from
0.00041570969851748523to `0.00313466280604876231. I.e. ~7.5 times. The absolute error is similar between the two runs, while the average salt flux decreased greatly for the new versions.While the jump in error is large, I think it may not actually be a cause for concern. It's an error between the mediator import and mediator export, which shouldn't be influenced by changes in the CICE and Icepack code. The intermediate update, where CMEPS and MOM were updated without CICE, showed a much smaller salt error.
I think the errors in mediator imports and exports could be due to their data being offset by one timestep.This seems consistent with the error pattern in the meltwater flux imports and exports in January and June:
I'm less sure about the very large decline in the salt flux magnitude between the two runs. A significant part of the difference appears to be in the Arctic in June:
EDIT: @MartinDix points out that the global year average salt flux ends up being a cancellation of different signed fluxes from different seasons, and in equilibrium should sum up to zero. This looks like it's the case in these two simulations, where the resulting in a global average is much smaller than the typical values during the year.
I think this suggests the change in yearly average salt flux is likely not a big cause for concern!
Atmosphere to ice fluxes
Details
The errors look largely similar for these fluxes.