CoAuthors

Craig Donlon (ESTEC/ European Space Agency, Netherlands); Achilles Tripolitsiotis (Space Geomatica, Greece); Constantine Mavrocordatos (ESTEC/ European Space Agency, Netherlands); Pierre Femenias (ESRIN/European Space Agency, Italy); Franck Borde (ESTEC/ European Space Agency, Netherlands); Xenofon Frantzis (Technical University of Crete, Greece); Constantine Kokolakis (Space Geomatica, Greece); Demitris Piretzidis (Space Geomatica, Greece); Thierry Guinle (CNES, France); Mingsen Lin (NSOAS, China); Yongjun Jia (NSOAS, China); George Vergos (Aristotle University of Thessaloniki, Greece); Robert Cullen (ESTEC/European Space Agency, Netherlands); Elias Tziavos (Aristotle University of Thessaloniki, Greece)

This work presents the latest calibration results for the Jason-3, Copernicus Sentinel-3A and -3B and the HY-2B radar altimeters as determined by the Permanent Facility for Altimetry Calibration (PFAC) in west Crete, Greece. To maintain Fiducial Reference Measurement status, the stability and quality of altimetry products need to be continuously monitored throughout the operational phase of each altimeter. External and independent calibration and validation facilities provide an objective assessment of altimeter’s performance by comparing satellite observations with ground-truth and in-situ measurements and infrastructures. Three independent methods are employed in the PFAC: Range calibration using a transponder, sea-surface calibration relying upon sea-surface Cal/Val sites, and crossover analysis.
Absolute biases for Jason-3 Passes No. 18, 109, Sentinel-3A Passes No. 14, 278 and 335, Sentinel-3B Passes No. 14, 71 and 335 as well as HY-2B Pass No. 280 are given. Diverse calibration results by various techniques, infrastructure and settings are presented and intercompared.
Finally, the activities for the establishment of a second range and sigma-0 transponder to operate under a Sentinel-6 “Michael Freilich” crossover location on the island of Gavdos, Greece are also summarized.