University of Colorado
The ESMF_RegridWeightGen software is a utility for generating interpolation weights from file. It is bundled with the Earth System Modeling Framework (ESMF) distribution and is an easy way to begin using ESMF regridding.
The software may be used in serial or parallel. It has been noted for its speed and stability by our users, who have reported that it allows them to compute in minutes weights which took hours with previous software, and allows them to compute weights in cases where other software failed.
The software takes in two grid files and outputs a file containing interpolation weights. It supports both logically rectangular and unstructured grids. The grid files may be specified in any of four different formats: the SCRIP format that is used as an input to the SCRIP application, the GRIDSPEC format following the CF metadata conventions, a custom ESMF unstructured grid format, or the proposed CF unstructured grid (UGRID) format. The weight file is specified in the same format as was used by the SCRIP application for consistency with existing applications.
ESMF_RegridWeightGen supports a variety of options for controlling the generation of interpolation weights. Five types of interpolation are supported: bilinear, higher-order patch, first-order conservative, and two types of nearest neighbor. There are multiple options for handling interpolation around the pole, and options for what to do if it is not possible to interpolate to a destination point. The software also supports masking and user-supplied areas for the first order conservative method.
There is also an option to check the weights produced by ESMF_RegridWeightGen. This option performs a regridding operation on an analytic field using the weights and computes both the interpolation error and the conservation error (if used with a conservative interpolation method). These errors are then output to the user.
For more information about the above please refer to the documentation for the 6.3.0rp1 release of ESMF_RegridWeightGen
ESMF_RegridWeightGen is being developed by the NOAA Environmental Software Infrastructure and Interoperability Group (NESII).