Numerical simulations of global-scale high-resolution hydrological crustal deformations

High-resolution load-induced crustal deformations calculated from numerical models are tested for their ability to predict hydrologically-induced station height variability, as they are known to be large enough to affect epoch-wise parameters obtained from the analysis of global geodetic networks. Loading contributions due to terrestrial water storage as given by global hydrological models are calculated on a 0.5 degrees global regular grid with daily temporal resolution. Apart from the dominant seasonal variations, the hydrological loading signal discloses also rapid changes exceeding 1 mm in several regions that can be associated with major precipitation events and river floods. Locally strong loading signals with exceptionally high amplitudes, in many cases even with nonseasonal nature, occur along the major river channels. Only high-resolution loading calculations considering also the water mass anomalies stored in the model river flow can resolve the correct amplitudes in the surrounded area up to 100 km distance. The comparison of the modeled hydrological surface deformation with GPS station time series shows that high-resolution hydrological loading estimates based on global-scale models are able to explain a considerable fraction (up to 54%) of the observed vertical station movements caused by continental water storage variations.