Page Comparison

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• Found the root cause of the “speckling” problem in the ne256 trigrid setup reported here: /wiki/spaces/NGDNA/pages/3597565953 This problem is due to the land->atmosphere state map being inconsistent with the land franction on the atmosphere grid. In particular, the map does not provide data in a few grids points where the land fraction is .30. At such a point, the atmosphere field is 30% land + 70% ocean, and since land will send no data, this results in temperature at a single point being consistently 30% too low. This is reported in the metric for “land frac consistency error” given in the page for the lnd2atm state map.

• Uses the python “holoviews” package which can directly plot unstructured grid data (by shading each polygon cell) manytimes faster than matplotlib’s ‘polycollection’ approach.

• The E3SM v3 trigrid setups have a small (but larger than expected) discrepancy between the land fraction computed from ocn->atm (computed from ocn2atm map) and ocn->lnd->atm (computed from domain.lnd + lnd2atm map). The metric for this is the “land frac consistency error” given in the page for the lnd2atm flux map. Andrew Bradley identified a likely source of this error, which is the default fminval=.001 in gen_domain. Land cells with a land fraction less than fminval are removed (land mask=0). For tri-grid we may want to consider lowering fminval, so that there are more land points and thus more likely that the lnd->atm map will provide data on all partial land atmopshere cells.

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