Publications

The Gravity Recovery and Climate Experiment (GRACE) has so far seen around 4 years worth of monthly gravity-field solutions being released to the scientific community. These are provided in the form of Stokes potential coefficients by the GRACE Science Data Service centers; the Center for Space Research, University of Texas (CSR), the GeoForschungsZentrum Potsdam (GFZ) and the Jet Propulsion Laboratory (JPL), as well as the Centre National d'Études Spatiales (CNES). We make use of the releases from these centers that have the longest time series, and infer temporal changes in the geoid for Australia by fitting a model incorporating secular, annual, and semi-annual terms to the time series of each of the Stokes potential coefficients that make up the solutions. Geoid change in Australia, neglecting oceanic and atmospheric contributions, arises mainly from hydrological processes, ongoing glacial-isostatic adjustment and present-day global ice-mass changes. Predictions are made of these contributions using models describing changes in continental water storage, ice-volume changes in the areas of major present-day ice cover, and the continuing viscoelastic response of the Earth to the last glacial-interglacial transition. The reliability of the inferred geoid-change terms is examined using several classical statistical tests, namely the Student t-test and the Fisher F-test. In addition, we apply the Wiener Optimal Evaluator to the original GRACE solutions to determine the preferred release.

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Fleming, K.; Martinec, Z.; Sasgen, I. (2006): Geoid change over Australia: analysis of the GRACE gravity field solution. AGU 2006 Fall Meeting (San Francisco, USA 2006).