A joint inversion of gravimetry, altimetry and GNSS to improve spatial resolution of Earth system mass change

Knowledge of Earth system mass change is limited to spatial scales of approximately 300 km x 300 km, as this is near the native resolution of the data collected from the GRACE and GRACE-FO (G/GFO) satellite gravimetry missions.  Measurements of surface height change at much finer spatial scales can additionally be exploited to derive mass change, albeit with the proper treatment of the data.  Here, we jointly invert inter-satellite range-rate measurements from GRACE and GRACE-FO, surface height changes measured by in-situ GNSS receivers, and surface elevation changes from a multi-mission synthesis of radar and laser satellite altimeters to estimate mass change at spatial scales of 100 km x 100 km within a Bayesian framework over the time period 2002 - 2021.  In this talk, we will focus on results over North America, where nearly 3,000 in-situ GNSS measurements are processed in combination with G/GFO, and over Antarctica, where Envisat, ICESat, CryoSat-2, and ICESat-2 measurements have been processed in combination with G/GFO.  We find agreement between the geodetic data combination solution and the G/GFO-only solution at large basin scales, but unique knowledge of mass change is gained with the geodetic data combination solution at smaller spatial scales not observed by satellite gravimetry alone.