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Found the root cause of the “speckling” problem in the ne120 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, resulting in a 30% error in state variables mapped to the atmosphere grid. 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.
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 and ocn->lnd->atm, suggesting the use of a mixture of different tools to compute ave maps or an inconsistency in the TR aave tool.
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