[G02-5] Altimetry and marine geoid

[G02-5-01] The GEOMED2 project: Geoid estimation in the Mediterranean Area

^○Riccardo Barzaghi¹, Georgios Vergos², Alberta Albertella¹, Daniela Carrion¹, Ilias N. Tziavos², Vassilios N. Grigoriadis², Dimitrios A. Natsiopoulos², Sean Bruinsma³, Sylvain Bonvalot³, Lucia Seoane³, Franck Reinquin³, Marie-Francoise Lequentrec-Lalancette⁴, Corinne Salaun⁴, Pascal Bonnefond⁵, Per Knudsen⁶, Ole Andersen⁶, Mehemet Simav⁷, Hasan Yildiz⁷, Tomislav Basic⁸, Matei Varga⁸, Olga Bjelotomic⁸ (1.Politecnico di Milano, Milano, Italy, 2.Aristotle University of Thessaloniki, Thessaloniki, Greece, 3.GET UMR 5563, Toulouse, France, 4.SHOM, Brest, France, 5.OCA/Géoazur, Sophia-Antipolis, France, 6.DTU Space, Kopenhagen, Denmark, 7.General Command of Mapping, Ankara, Turkey, 8.University of Zagreb, Zagreb, Croatia, 9.University of Jaén, Jaén, Spain)

The GEOMED2 project has been set up in order to compute an updated estimate of the geoid in the Mediterranean area. In this work, the geoid computation based on gravity data collected in the area 29o<lat.<48o -10o<lon.<41o, covering the entire Mediterranean basin, is presented. Outlier rejection and data homogenization have been carefully performed on the entire database. Low frequency components of the gravity field have been modelled using the more recent global geopotential models, such as EIGEN-6c4 and satellite only derived models (namely those based on the GOCE mission). Reduction for the terrain effect has been also accounted for using the SRTM Digital Terrain Model that has been complemented with bathymetric data. In computing the geoid, different methods have been considered. Collocation, Fast Collocation, Stokes and Stokes/FFT have been applied and discrepancies among the different estimates have been evaluated and discussed. The obtained geoid solution will then allow estimating a refined SST, both over open-sea and coastal areas, which will be used to compute permanent and seasonal currents in the Mediterranean Sea that are relevant to many physical phenomena (e.g. climate changes).