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To remap data from the SE grid to other grids, ACME relies on ESMF mapping utilities. ESMF's conservative remapping algorithm can currently only map cell centered data. For every point in the mesh, ESMF treads treats that point as a cell average value, and requires that we specify the its cell boundaries as a polygon. These polygons are the dual grid to the SE subcell grid. For conservative remapping, the areas of these polygons must match the Gauss-Lobatto weight of each Gauss-Lobatto node. If we construct this dual grid in the usual way, by connecting the centers of all the subcells shown in the subcell grid, the areas of the cells will in general not match the Gauss-Lobatto weights. We thus have to perform an iteration, similar to spring dynamics, tweaking the polygons until the areas are correct. We have a couple of algorithms to do this, none of which are perfect. The result of this procedure one of these algorithms is shown below:
TempestRemap
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