Can Continental and Ocean Water Mass Variability from Satellite Gravimetery be Used to Correct for the Loading Signal in Geodetic Time Series?

Model estimates of the annual variations in continental water storage are of sufficient magnitude to induce peak-to-peak changes in the vertical position of geodetic stations of up to 3 cm seasonally. Signals of this magnitude need to be removed from the geodetic data if the geodetic trend is to be interpreted in terms of geodynamic processes. Unfortunately, considerable errors are probably present in the model-derived water storage estimates due to errors in the model forcing, parameters and model formulation. If these models are used to correct the geodetic data, it is likely that the continental water storage signal is being improperly removed from the geodetic data sets. A number of satellite gravity missions have been recently launched, or will come online in the near future, that will measure changes in Earth's surface hydrology with unprecedented accuracy. Gravity missions such as CHAMP, GRACE and GOCE, and other satellite missions have the potential to significantly improve our understanding of many hydrologic processes, as well as improving our ability to monitor and predict the partitioning of continental water mass into snow, precipitation, soil moisture and ground water. In this paper, we investigate the possibility that estimates of water storage variations derived from satellite gravity missions can be used to correct geodetic data for the long wavelength component of the water storage signal.