The GAVDOS Mean Sea Level and Altimeter Calibration Facility: Results for Jason-1

Abstract

The location of the GAVDOS facility is under a crossing point of the original ground-tracks of TOPEX/Poseidon and the present ones for Jason-1, and adjacent to an ENVISAT pass, about 50 km south of Crete, Greece. Ground observations and altimetry comparisons over cycles 70 to 90, indicate that a preliminary estimate of the absolute measurement bias for the Jason-1 altimeter is 144.7 ± 15 mm. Comparison of Jason microwave radiometer data from cycles 37 and 62, with locally collected water vapor radiometer and solar spectrometer observations indicate a 1–2 mm agreement.

Keywords:

• calibration
• validation
• radar altimetry
• sea level
• GPS
• water vapor
• Jason-1
• ENVISAT

Notes

*Two events (ascending/descending) at five locations over 43 cycles, except for one site with only one event/cycle.

†Two events (ascending/descending) at five locations over 61 cycles.

1COSPAR 2004 results.

2Present analysis.