Sea surface topography by airborne laser altimetry and offshore GPS buoys in the Eastern Mediterranean: Comparison with JASON-1 radar altimeter data and GRACE gravity field

Abstract

Satellite radar altimetry is the basic means for global-scale sea surface height (SSH) monitoring, constituting a major source for gravity field improvements. In order to contribute to the improvement of sea level monitoring and to provide local-scale information on the short-wave structure of the marine gravity field, enhanced ground-based methods for precise SSH measurements have been developed, consisting in airborne laser altimetry, shipborne multi-antenna GPS measurements and GPS-equipped buoys. Two local survey areas were chosen in the vicinity of JASON-1 ground-tracks in the Eastern Mediterranean. The gathered SSH data could ultimately allow to contribute to the validation and calibration of radar altimeter missions. Preliminary SSH results from airborne laser altimetry and offshore GPS surveys are presented. Furthermore comparisons with JASON-1 radar altimeter data and geoid heights from both EGM96 and GRACE-based GGM02 models are made.