Mass redistribution from global GPS timeseries and GRACE gravity fields: Inversion issues

Monitoring hydrological redistributions through their integrated gravitational effect is one of the primary aims of the GRACE mission. Yet it has been proposed that at larger scales this may be achieved independently by measuring and invert- ing the elastic loading associated with redistributing masses, e. g. with the IGS network. This is particularly interesting as long as GRACE monthly gravity solutions not (yet) match the targeted baseline accuracies at the lower degrees. In this contribution (1) we describe a joint inversion technique, (2) we introduce a physically motivated regularization that guarantees stable inversion results if only GPS data is used, (3) we apply this technique to GPS data pro- vided by the IGS service covering recent years, and (4) finally we compute what the relative contribution of GRACE and GPS would be in a joint inversion.