Validation of EOST loading service using global GPS solutions

The circulation of the surface geophysical fluids (atmosphere, oceans and continental hydrology) induces global mass redistribution and therefore global Earth deformations, recorded for example by permanent GNSS networks.

Models of surface displacements due to atmospheric, non-tidal oceanic and hydrological loading are available at the EOST loading service (http://loading.u-strasbg.fr) as time series for ITRF sites, but also as global maps.

We present here a comparison of a global GPS solution with these loading models, and show that loading effects can only explain a maximum of 50 percent of the observed vertical displacements, especially at mid- and high-latitude regions. On the other hand, at low-latitudes, the variability of modeled displacements is much lower than the GPS solutions.

In a later step we include the loading models at the observation level and show how the global solution is improved on the entire spectrum, i.e. from a few days to secular