Evaluation of Temporal Variations on the Gravity Field Caused by Geophysical Fluids and Their Possible Detection by GRACE

We tried to model an artificial geoid signal and than decompose it into its causes. First we modeled the geoid heights changes caused by the hydrosphere and the atmosphere, and composed them to simulate the measurable signals by GRACE. Then, we decomposed the signals by considering the following properties; 1) different ocean responses to atmospheric pressure changes, and 2) different time-frequencies of the variations of the hydrospheric contributors. These tests prove that an appropriate assumption for the ocean response is important to minimize decomposition errors. Since atmospheric errors necessarily affect the recovered hydrospheric signal, minimization of these errors by mathematical tricks is desired.