code: (PR to E3SM PreAndPostProcessing repo): https://github.com/E3SM-Project/PreAndPostProcessingScripts/pull/53
The page documents a python utility to analyze E3SM map files. It checks the the key properties that can be examined by NCO (ncks --checkmaps), and several additional properties, including consistency with the land/ocean fractions induced by the flux maps. It’s currently setup to examine all mapping files from a working E3SM case by parsing the XML files after running ./case.setup. It produces a latex file, which can then be processed into a PDF report.
...
This was a 2023 summer intern project (Dallin Seyfrield ( BYU ), Drew Sukova (Purdue), Mark Taylor ). Funded by the E3SM ECP project. For code and instructions on how to run, see the README file in: https://github.com/E3SM-Project/PreAndPostProcessingScripts/tree/master/regridding/map_file_analysis
Some highlights:
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. This error suggests that a mixture of different tools to compute ave maps and domain files, or an inconsistency in the TR aave tool. (The older ne256 trigrid setup has much smaller errors for this metric and it’s flux maps may have been computed with nco or esmf).
...