CoAuthors

Ole Andersen (DTU Space, Denmark); Nikolai Maximenko (University of Hawaii at Manoa, USA); Jan Hafner (University of Hawaii at Manoa, USA)

Within the ESA supported Optimal Geoid for Modelling Ocean Circulation (OGMOC) project an optimally combined geoid model was derived. It is based on the GOCO05C setup, though the newer DTU15GRA altimetric surface gravity was used in the combination. The OGMOC geoid model was optimized to avoid striations and orange skin like features. Subsequently the model has been augmented using the EIGEN-6C4 coefficients to d/o 2160. Also, a newly updated mean sea surface was used. Compared to the DTU15MSS, the DTU18MSS has been derived by including re-tracked CRYOSAT-2 altimetry also, hence, increasing its resolution. Some issues in the Polar regions have been solved too.
Initially, a new geodetic DTU19MDT was derived using the OGMOC geoid model and the new DTU18MSS mean sea surface. The processing scheme was similar to the one used for the previous geodetic DTU17MDT model. The filtering was re-evaluated by adjusting the quasi-gaussian filter width to optimize the fit to drifter velocities. The results show that the new MDT improves the resolution of the details of the ocean circulation. Subsequently, the drifter velocities were integrated to enhance the resolution of the MDT. As a contribution to the ESA supported GOCE++ project DYCOT a special concern was devoted to the coastal areas to optimize the extrapolation towards the coast and to integrate mean sea levels at tide gauges into that process. The presentation will focus on the coastal zone when assessing the methodology, the data and the final model DTUUH19MDT.