GNSS2TWS_Slepian: A software to recover daily GNSS-inverted terrestrial water storage changes based on Slepian basis functions

Abstract

Changes in terrestrial water storage (TWS) can deform the Earth’s solid surface in the form of geodetically measurable vertical motions. Here, a new open-source Matlab software, named GNSS2TWS_Slepian, is developed to achieve the recovery of daily TWS changes from Global Navigation Satellite System (GNSS) crustal vertical positions. Differing from the widely-used spatial-domain inversion strategy based on Green's function method, our inversion modeling is implemented in the spectral domain based on Slepian basis functions, which aims to infer daily large-scale TWS changes using non-uniformly distributed GNSS vertical data. GNSS2TWS_Slepian is designed with different structured modules and the logic of the program workflow can be easily followed. To obtain daily estimates of TWS changes, the principal component analysis is integrated into our time-varying inversion model. To demonstrate the main functionalities, equivalent water height changes are investigated in the Western United States. This study aims to provide a scientific mathematical tool for resolving large-scale water mass loads, which is instrumental in broadening the applications of GNSS in hydrology.