Now that this forum exists, I was hoping I could flag an issue that was uncovered a couple years ago but was languishing in my to-do list regarding the ACCESS-CM2 runs.
It looks like the time-integrated heat flux into the ocean (‘hfds’ variable) does not equal the time-integrated ocean heat content (calculated using the ‘thetao’ variable), in both the historical and piControl runs. I should note that this is NOT an issue in the raw outputs, just in the published CMIP data. Here’s the mismatch in the historical runs:
In the piControl runs, @rmholmes found that the non-closure is because some terms are neglected in the ‘hfds’ calculation:
Just to clarify for others - the problem is with the pre-processing that computes the ESMF/CMIP output variable hfds from the raw MOM5 output diagnostics. The old calculation (“abhi-hfds” above) did not include frazil formation below the surface layer (frazil-2d vs. frazil-3d) or some components of the heat flux associated with surface volume fluxes (a few terms to do with ice-ocean fluxes). The “ryan-hfds” calculation above correctly includes all of these terms.
Technical note: To close the heat budget exactly you should technically also be comparing the time integral of area-integrated hfds to snapshots of the global OHC, not time-averages of OHC. This point is minor compared to the difference that Taimoor is showing above in the first plot, as shown by the second plot.
@MartinDix I assumed the “pre-processing” referred here was Chloe’s ACCESS-Archiver, but I can’t find any mention of it in the gitlab repo. Where is this calculation done? It seems like a bug which should be fixed.