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For PG2 data, to remap from FV (unstructured) to FV (latlon), we dont yet have an integrated bilinear option. ESMF’s “aave” option ( which can be obtained most efficiently using NCO’s ncremap) is conservative and good for downscaling, but will produce blocky plots when upscaling. For nicer looking plots when upscaling, ESMF’s “bilinear” is currently the only option.

Dual grid (GLL data)

Data on the SE grid is awkward to work with primary because the data on the Gauss-Lobatto-Legendre (GLL) grid exists at cell vertices (i.e., data is point values), while most existing analysis tools expect cell-centered data (i.e., data points represent values over some representative area bounded by each “cell”). We can sort of mimic this cell-centered view by constructing a new mesh that is a “finite volume dual grid” to the SE GLL grid, in which we construct bounding polygons around each GLL node and pretend that the data at the GLL node is representative of the value across the area of the polygon. When adding a new SE grid to E3SM, we construct a SCRIP-formatted file with this information, primarily because some of our remapping tools used to/still do require this cell-centered representation of the data. And example can be found in the inputdata repository for the ne4np4 grid here:

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