Improving the estimation of Earth's gravitational potential for better ocean level assessment using GRACE data: encouraging first results

The objective of this study is to improve the determination of the Earth gravitational potential, especially the low-degrees, using GRACE observations to obtain a better assessment of ocean level variations. One of the main sources of error in the closure of the sea level budget is related to the knowledge of the ocean mass changes.To address this issue, we have tested new orbit adjustment parametrizations for the gravity field estimation. We analyze errors associated with the dynamics models and measurements to better understand the sources of the uncertainties.The poster presents the initial results from several parametrization schemes, including approaches that adjust the use of onboard data to reduce noise and improve signal recovery. A new assessment tool developed by Magellium for CNES was employed to evaluate the effectiveness of these strategies, showcasing encouraging improvements in particular C20 harmonic coefficient.