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IMAU-paleo / UFEMISM2.0

Version 2.0 of the Utrecht FinitE voluMe Ice-Sheet Model
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Ice shelf area conservation #14

Open erwinlambert opened 4 months ago

erwinlambert commented 4 months ago

After remeshing, the calving front advances. This should be conserved, ideally with partial grid cells.

Also, in some cases a hole appears after remeshing in the middle of an ice shelf, which fills again after the next remeshing. Looks like a bug

erwinlambert commented 4 months ago

Calving front advance may/may not be related to calving front relaxation. In ice_model_main.f90, in l. 844 relax_calving_front is hardcoded in (not within an IF statement depending on the config flag).

Additionally, the noice mask is enforced before calving front relaxation, not after it. Hence, area is not conserved. Either reordering these routines, or repeating apply_mask_noice_direct after l. 844 may be necessary

erwinlambert commented 4 months ago

In addition to the remapping, some calving front advance (bleeding?) into the noice region occurs. As the ice thickness near the CF thins, the area that is gained temporarily seems to increase. The area gain is corrected after 1-2 years. So apply_mask_noice_direct should probably be applied somewhere at each time step to fix this.

Note: this area gain / CF advance does not only occur during/after remapping. Example:

frame_017 frame_018

erwinlambert commented 4 months ago

Commenting out CF relaxation does not resolve the issue. After remapping, ice thickness values of +/- 1e-xx (small, both positive and negative) remain in front of the calving front, in the noice region. These seem to oscillate between positive and negative, and, when positive, leading to an expanded ice shelf mask.

To be tested: