Regridding is a crucial step in climate and weather modeling. It allows scientists to transfer information between climate models that use different types of grids to represent the Earth. These grids can have different shapes, sizes, or orientations, and transferring data between them accurately is challenging. If handled poorly, errors can build up over time and reduce the reliability of climate predictions.

This study provides an overview of how regridding should be correctly addressed from a geometric perspective, how it is currently implemented in climate models, and why this accuracy matters. We explain the basic components of the process, including how grids are represented and how overlapping regions are calculated. Special attention is given to correctly handling certain boundaries, such as those following lines of latitude, which is essential for physically meaningful results.

We also summarize how leading tools approach these challenges and highlight differences in their methods. Our work underscores the importance of accurate geometry in regridding calculations and calls for more direct comparisons of advanced tools to evaluate both their accuracy and speed. These insights can help improve future climate models, making them more reliable for understanding our changing planet.