Hydrological Loading in Western Europe Estimated from the Inversion of GPS Displacements computed with GINS/PC software
Abstract
Since the launch of the GRACE satellites in 2002, followed by GRACE-FO in 2018, the determination of seasonal hydrological variations has been significantly improved. These surface mass variations also induce crustal deformation which can be measured by GNSS permanent stations. In this study, we produce a dense GPS solution in Western Europe using the GINS/PC software developed by CNES. We compare the solutions of Precise Point Positioning processing with or without fixing the integer ambiguities. Displacements can be linked to mass loading process using the Green's functions formalism, assuming an elastic or anelastic Earth models. The observed displacements are then inverted in order to recover hydrological seasonal variations. We use a regularized least square inversion for vertical and horizontal displacements and compare our estimations to GRACE solutions and global hydrological models. We show that dense and homogeneous GPS networks allow a retrieval of mass variations with spatial resolution equivalent or even better than GRACE.