Inversion of GNSS Vertical Displacements for Terrestrial Water Storage Changes Using Slepian Basis Functions

The surface displacements measured by the Global Navigation Satellite System (GNSS) provide a unique insight for studying terrestrial water storage (TWS) changes. In this study, we recovered TWS changes from GNSS vertical in Southwest China (SWC) using Slepian basis function (SBF) January 2011 to December 2020. performance of estimated SBF was validated against Gravity Recovery and Climate Experiment (GRACE)/GRACE Follow-On (GFO) GNSS-inverted Green's method. results showed that spatial patterns, seasonal, linear trends derived agreed with GRACE/GFO estimates. However, there are still evident differences local scope, GNSS-derived presented stronger amplitudes more details spatio-temporal domains than estimates SWC. unconstrained inversion also signal those function, were reliable method regions sparsely distributed stations Additionally, average distance between can be considered as reasonable filtering radius SBF, SBF-estimated different Gaussian radii had comparable patterns GRACE/GFO.