References

[milankl]

Just came across this which talks about 1st and 2nd order conservative remapping

https://www.dwd.de/EN/ourservices/reports_on_icon/pdf_einzelbaende/2019_03.pdf?__blob=publicationFile&v=1

[asinghvi17]

https://gmd.copernicus.org/articles/10/425/2017/ is the source paper on that 2nd order method. their acceleration approach is, hilariously enough, very similar to what we did in SphericalSpatialTrees and what I plan to do here.