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, Vassilis^5
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.