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MPAS-Dev / MPAS-Model

Repository for MPAS models and shared framework releases.
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Remapping of terrain height and other static fields is incorrect for `bdyMaskCell == 7` cells #1149

Closed mgduda closed 5 months ago

mgduda commented 5 months ago

If static fields are remapped to a regional mesh, cells whose bdyMaskCell value is 7 (i.e., those cells forming the outer specified zone) do not receive correct values.

This issue does not occur when remapping static fields to global meshes, and so a workaround is to remap static fields to a global mesh before creating a regional subset (rather than the reverse: subsetting a global mesh and then remapping static fields).

mgduda commented 5 months ago

Leading up to the MPAS v8 release, we migrated the routines for checking whether a point is within a cell into the mpas_geometry_utils module, and in doing so, we replaced a call to sphere_angle with the shared mpas_sphere_angle routine. Unfortunately, the mpas_sphere_angle routine only works for a unit-radius sphere, while the interpolation of static fields happens on an "earth-sized" sphere, leading to errors in determining whether pixels whose nearest cell center was a specified-zone cell were in that cell.

mgduda commented 5 months ago

Closed by PR #1148.