CoAuthors

Sean Bruinsma (CNES, France); Frank Reinquin (CNES, France)

A new model of marine free-air gravity anomalies has been determined. It is based on the same data set used in the CNES CLS 2019 Mean Sea Surface determination. Particular attention is paid to the shortest wavelength of the geoid of less than 30 km. Furthermore, data sampling at 1 Hz (~7km) along track is not sufficient in this context. It is necessary to focus this new determination on the use of 20 Hz (~350m) data that are provided by a new generation of altimeter, such as the Jason-1/2, Cryosat-2, and also SARAL missions in the geodetic phase. However, at this rate, observations are too noisy. They are resampled at 5 Hz cadence after application of a dedicated optimal filter.
We will present the validation of this new marine gravity field by means of comparing with existing models like UCSD V27 and DTU15, and the high-resolution GEOMED2 (ship) gravity database of the Mediterranean in particular.