New ocean variables for floating land ice #5464
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See E3SM-Ocean-Discussion#38 for further discussion |
TestingMachine: chrysalis The PR test suite passes comparison with baseline for all tests except Furthermore, I ran all of the |
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@jonbob, I'm marking this as |
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As I have discussed with @cbegeman, this can't go in until we get new initial conditions for all New ICs:
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I used commands like: to add the new variables. |
| !$omp parallel | ||
| !$omp do schedule(runtime) | ||
| do iCell = 1, nCells | ||
| dThreshMLD(iCell) = dThreshMLD(iCell) - abs(landIceDraft(iCell))*landIceMask(iCell) | ||
| dThreshMLD(iCell) = dThreshMLD(iCell) - abs(landIceDraft(iCell)) | ||
| end do |
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@vanroekel, this is the piece of code I'd like to get your input on. It's the only thing that I think will lead to non-BFB results in fields that could feed back on model dynamics.
I think I masked this with the landIceMask before without really thinking about the consequences. But the ice draft is smoothed near the ice-shelf calving front on both the iceward and seaward sides. It seems like we should remove this ice draft (the amount that the sea surface is depressed by the weight of an ice shelf) even in open ocean areas where it is nonzero (maybe 10 cells seaward of an ice shelf at most).
I just wanted to check with you because you'll have the best sense of what fields we should be testing for changes as a result of modifying dThreshMLD. Which parts of the eddy parameterizaiton are affected?
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@xylar thanks for the explanation on the change. I agree that if we have an added pressure on the sea surface we should account for this and so it makes sense to remove that iceMask.
At minimum this will cause some changes in the submesoscale eddy parameterization, my feeling is it will strengthen as I'd expect MLD to deepen with this change where the ice pressure wasn't being removed previously. So checking the MLEvelocity (normal and vertical) fields would be a good start.
If you have redi enabled, I'd expect very slight changes there as well. For that one you could take a look at the temperature_hmixTendency (or salinity) variable, assuming the tracer budgets are on. But again am expecting small changes.
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@vanroekel, thanks for your intuition on what will change.
I'd expect MLD to deepen with this change
I could be wrong but I expect the opposite -- I think the MLD was artificially deep because the old code didn't account for the fact that much of that depth was actually because the sea surface was suppressed by land ice.
So it may be that we would expect a weakening of those parameterizations around ice-shelf fronts. I'll take a look and see which it is.
Thanks again!
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Sorry you are right @xylar I thought this bit of code was correcting the pressure when finding the reference pressure level, but is a correction to the MLD itself. Yes MLD will definitely shallow with this change.
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@jonbob, I'd like to do a bit-for-bit test for each of the 6 meshes with ice-shelf cavities. Is there a way to do that with the E3SM testing infrastructure (i.e. do we have short test runs for all 6 meshes)? If not, do you have an alternative suggestion for how I could do this efficiently? |
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@jonbob, following up, I'm going to see how far I can get with tests like: Let me know if you suggest something different. |
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@xylar -- that's pretty much what I was going to suggest |
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Holy cow! It works! |
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I'll have to pick this up tomorrow but I should have my 6 baselines by then. |
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I ran 6 baseline tests using 0a642b7 as the baseline (the commit on master where this branch was created). 5 of 6 show diffs in many fields:
One test, Overall, my results are in the subdirectories of: |
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@cbegeman, I think the actual issue is just that oQU240wLI was never set up to use data icebergs. So both the baseline and the comparison runs failed. I think the error about the SSH being outside of bounds is just because there's a check that should be turned off, but as you say it's unrelated to the main failure. |
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From the sea ice log file for both oQU240wLI runs: |
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Comparison of 10-year test with baseline, using ne30pg2_ECwISC30to60E2r1 and CRYO1850 configurations, are available at: 20230227.5464test.anvil. @xylar and @cbegeman, please make sure this looks OK to you -- and invite anyone else to review based on these results. |
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@vanroekel, just waiting on your approval based on my questions about the MLD changes. It looked like you were okay with them. |
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@cbegeman -- I went to test this before merging and now getting an error from mpaso: But the tests all use non-wISC grids -- my longer run was with ECwISC30to60E2r1. |
The new initial conditions have: * `landIceFloatingMask=landIceMask` * `landIceFloatingFraction=landIceFraction`
We want `config_land_ice_flux_mode` to be `off` for most meshes but to be one of: * `pressure_only` (default) * `standalone` if `$OCN_ISMF = internal` * `coupled` if `$OCN_ISMF = coupled`
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…5464) New ocean variables for floating land ice This PR adds new variables to represent floating land ice. This is a necessary step toward coupling with an ice sheet model component (MALI). * landIceMask and landIceFraction (existing variables) now represent both grounded and floating land ice. * landIceFloatingMask and landIceFloatingFraction (new variables) represent only floating land ice. The landIceFloating* variables are used to modulate land ice fluxes, whereas the landIce* variables are used to mask out certain fields, as before. landIce* variables also modulate top drag, as we want to include the effect of top drag on thin film regions to slow flow. [NML] [non-BFB]
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passes:
with expected NML DIFFs and BFB for grids without ice shelf cavities merged to next |
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merged to master and expected NML DIFFs blessed |
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Was this actually non-BFB for any of our tested cases? |
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@rljacob -- I don't think so, after re-reading the discussion above |
This PR adds new variables to represent floating land ice. This is a necessary step toward coupling with an ice sheet model component (MALI).
landIceMaskandlandIceFraction(existing variables) now represent both grounded and floating land ice.landIceFloatingMaskandlandIceFloatingFraction (new variables)represent only floating land ice.The
landIceFloating*variables are used to modulate land ice fluxes, whereas thelandIce*variables are used to mask out certain fields, as before.landIce*variables also modulate top drag, as we want to include the effect of top drag on thin film regions to slow flow.[NML]
[non-BFB]