17. Consistency of GOCE Geoid Information with in-situ Ocean and Atmospheric Data, Tested by Ocean State Estimation

Ocean state estimation is a powerful method to test the consistency of data sets assimilated into an Ocean General Circulation Model (OGCM) among each other and with the initial and boundary conditions of the model. We apply the GOCE-GRACE combined GOCO01s geoid model to reference temporal Mean Sea Surface (MSS) height measured from satellite altimetry to derive the Mean Dynamic Topography (MDT). The consistency of this MDT with ocean and atmospheric data is tested through application of the GECCO (German part of Estimating the Circulation and Climate of the Ocean) model. Three optimizations are performed: One as a reference run applying usual data sets but without assimilation of MDT, and two integrations applying different MSS models in the computation of the MDT. We find improved performance of the state estimation, if MDT is assimilated. The choice of the MSS, however, has no significant impact on the optimization. The MDT is overall consistent with both, the other assimilated ocean data sets as well as the atmospheric forcing.