Per Knudsen (Technical University of Denmark, Denmark); Jan Hafner (IPRC/SOEST, University of Hawaii, United States)

GOCE mission and OGMOC analysis resulted into a major improvement of the geoid model and geodetic mean dynamic topography (MDT) products. In this study we validate these products using a combination of most recent in-situ and satellite oceanographic data, including trajectories of drifters, sea level anomaly, and wind. Geographical distribution of the discrepancies is derived in a broad range of space scales.

Particular attention is paid to ageostrophic processes and uncertainties in oceanographic data and their influence on the accuracy of dynamic topography estimates. This includes effects of wind-driven currents and inertial oscillations as well as effects of methods used to filter out these motions. The latter filters are shown to have significant impact on representation of strong meandering jets in the dynamic topography.

The local statistics of the mean dynamic topography estimates, derived from repeat oceanographic observations, are analyzed under various sea state conditions and at different stages of the evolving observing system.

Finally, geodetic and oceanographic data are synthesized into a new high-resolution mean dynamic topography product. We also discuss limitations of thus-far accumulated historical observations with respect to the future improvement of the MDT accuracy and resolution.