CoAuthors

Per Knudsen (DTU Space, Denmark); Luca Centurioni (Scripps Institution of Oceanography, United States); Ole Andersen (DTU Space, Denmark); Jan Hafner (IPRC/SOEST, University of Hawaii, United States); Oleg Melnichenko (IPRC/SOEST, University of Hawaii, United States)

The new mean dynamic ocean topography (MDOT) is the result of an international collaboration between experts on different satellite and in situ observing systems. Using variational technique, the product combines gravity-based and currents-based MDOT's, the former having advantages on a large scale and the latter extending into a mesoscale. Compared to previous generation, the new MDOT utilizes recent results of the 'Gravity field and steady-state Ocean Circulation Explorer' (GOCE), a new dataset of drifter velocities, having significantly better global coverage, that was reprocessed with the enhanced drogue presence detection technique, and new generation of the AVISO maps of sea level anomaly. Methodologies of filtering, scale selection, Ekman current parameterization, and "drogued-undrogued" drifter velocity bias elimination are also improved.

The threshold scale for variational blending of the two source MDOT's is selected after careful comparison of errors and correlations, which revealed remarkable spectral overlap, ensuring high accuracy of the synthesized MDOT.

The quality of the product is demonstrated in dynamically complex regions of the ocean and co-existence of high eddy activity with the reach spatial structure of time-averaged currents is discussed. Local MDOT scales, resolved by the existing Ocean Observing System are analyzed, mapped, and compared with the scales of essential dynamical ocean features.