[G02-5] Altimetry and marine geoid

[G02-5-06] Comparing marine gravity and satellite altimetry in the Mediterranean area

^○R. Barzaghi¹, D. Carrion¹, C. De Gaetani¹, A. Albertella¹, G. Vergos², A. Abulaitijiang³, O. Andersen³, P. Knudsen³, I. N. Tziavos², M.-F. Lequentrec-Lalancette⁴, C. Salaun⁴ (1.Politecnico di Milano, Milano, Italy, 2.Aristotle University of Thessaloniki, Thessaloniki, Greece, 3.DTU Space, Lyngby Denmark, 4.SHOM, Brest, France)

The combination of altimeter data and gravity allows an effective estimation of the Mean Dynamic Topography (MDT) at sea. The MDT allows then estimating the oceanic currents, a crucial information in hydrological analysis and oceanographic studies. This is of particular interest in closed seas, such as the Mediterranean Sea, due to the impact that marine physical phenomena can have in such a heavily populated area. In this work, detailed computations are carried out for comparing marine gravity data and satellite altimeter observations. Particularly, Cryosat-2 data are compared with marine gravity data in the Mediterranean area. This is done by collocation in the framework of the remove-compute-restore procedure. Different data reduction procedures based on different Global Geopotential Models and bathymetric models have been carried out in order to evaluate their impact on the final MDT and current estimates. The results have been discussed also in the framework of the Geomed2 project in view of the estimation of a refined and updated MDT surface in the entire Mediterranean basin.