Steep Bathymetry Changes Close to the Coast as Sensed with Altimetry at the Gavdos Permanent Cal/Val Facility
Mertikas, Stelios1; Daskalakis, Antonis2; Tziavos, Ilias3; Andersen, Ole B.4; Vergos, George3; Zervakis, Vassilis5
1Technical University of Crete, GREECE; 2Space Geomatica Ltd., GREECE; 3Aristotle University of Thessaloniki, GREECE; 4Danish National Scapce Center, DENMARK; 5University of Aegean, GREECE

This work outlines how changes in steep bathymetry (from 200 m to 3500 m depth over a distance of 10 km) close to the coast are reflected on the determined sea surface anomalies at the Gavdos permanent site used for satellite altimeter calibration. After almost 4 years of Jason-2 calibration, it has been observed that in some calibration regions, south of Gavdos Cal/Val, and along the Passes No. 018 and No. 109, certain features in the produced bias showed a permanent characteristic that required further explanation as to its causes. Some of these features seem to be related to the general oceanographic circulation (anticyclonic currents), but others are related to inaccurate geoid model resolution and bathymetry changes. Finally, this work describes the relation between these parameter trends and the region's local characteristics.