Footprints were produced using LPDM, based on meteorology from a custom WRF setup described in Barkley et all 2022 or 2023 (I swear the year keeps changing. Just look for the Permian one).
Data goes from 2020-mid 2023.
Footprints are in units of ppb/(mol/(hr km^2)).
Personally, I'm more confident in the HYSPLIT footprints, but both give similar results in the Permian, so I wouldn't overthink it.