Most of these features are tied to differences in precip - so possibly a signal of interannual variability rather than a more systematic change in carbon cycle.
Most of the surface cooling (associated with the revised solar constant) is in the northern hemisphere - though note that the 2K near-Antarctic warming signal seen in previous comparisons between December 2024 runs and February 2025 runs is also mitigated).
Current time series of surface ocean temperature, and volume averaged ocean temperature from the current runs (test3 is an extension of @pearseb’s Spin up started in December i.e. older CABLE) Note that the two April Spinup start from the year 61 of the Test3 ocean (land restart is sourced from MarchEpot test run). Key difference between these simulations is that solar constant is reduced (to CMIP7 value) in the April run (and other land-based differences).
Equivalent plots for surface and volume-averaged salinity. Key difference is that the updates to CABLE-UM coupling have resulted in better water conservation. lprec is a tuning factor used to add fresh water to the ocean (ideally should =0, i.e. green line; blue and red use the same value).
Following this morning’s discussion, @dougiesquire and I have looked into the UM versions used in @pearseb’s spin up simulation. The git history for manifests/exe.yaml file in the experiments repository shows that the same UM executable was used in all the years that have been uploaded to the repository (0-766). We can confirm this is true for the remaining years once @pearseb has pushed the remaining runlog commits to Github. The UM executable used is at:
We’ve tried separately rebuilding a UM executable by specifying this commit hash, and reran year 770 of the spinup with the new executable. The output with the rebuilt executable is identical to the original spinup, suggesting that this is the correct version.
It would be great to for the more recent experiments to be uploaded to the experiments repository, as it helps a lot with this type of investigation.
@RachelLaw@tiloz - BREAKING NEWS - CMT is not active. namelist element deep_cmt_opt =1, a non-existent case. Is this supposed to be set to case = 2 @arnoldsu ?
The new field table is now being used. This is the April run (AprilSpinUp) and we can see the big change in the ocean net carbon flux (annual mean values [PgC/yr]). @pearseb is this what you expected? Looks like we went too far the other way.
