Predictions of global crustal deformation from forward simulations of terrestrial water storage

Non-tidal loading processes due to variations in atmospheric surface pressure, ocean bottom pressure and terrestrial water storage cause vertical crustal displacements of several millimeters on subdaily to seasonal time scales. These deformations are well reflected in positioning time series from GPS sites and, thus, affect epoch-wise parameters obtained from the analysis of global geodetic networks. In this contribution high-resolution load-induced crustal surface deformations derived from numerical model simulations are tested for their ability to predict hydrologically induced station height variations. Apart from the dominant seasonal variations, the hydrological loading signal contains also rapid changes exceeding several millimeters that can be associated with major precipitation events and river floods. Locally strong loading signals with exceptionally high amplitudes occur along the major river channels even on non-seasonal scales. As the horizontal resolution of water mass distributions from global hydrological models are typically limited to 0.5x0.5 degree, the water masses stored in the modeled river flow have to be reallocated on a high-resolution river network to resolve river loading deformations for stations at the river banks, like at Manaus where peak-to peak height variations of 70mm are observed. By comparing analyses of modeled hydrological surface deformations and GPS station time series it will be demonstrated that high-resolution hydrological loading estimates based on global-scale models accounting for water mass anomalies in river flows are able to explain significant parts of observed vertical station movements.