Calibration of TOPEX/Poseidon and Jason Altimeter Data to Construct a Continuous Record of Mean Sea Level Change

Abstract

Jason, the successor to the TOPEX/POSEIDON (T/P) mission, has been designed to continue seamlessly the decade-long altimetric sea level record initiated by T/P. Intersatellite calibration has determined the relative bias to an accuracy of 1.6 mm rms. Tide gauge calibration of the T/P record during its original mission shows a drift of −0.1 ± 0.4 mm/year. The tide gauge calibration of 20 months of nominal Jason data indicates a drift of −5.7 ± 1.0 mm/year, which may be attributable to errors in the orbit ephemeris and the Jason Microwave Radiometer. The analysis of T/P and Jason altimeter data over the past decade has resulted in a determination of global mean sea level change of +2.8 ± 0.4 mm/year.

Keywords:

• Jason
• TOPEX/POSEIDON
• calibration
• verification
• sea level

Acknowledgments

The authors would like to thank D. P. Chambers, T. J. Urban, A. Cazenave, B. J. Haines, R. Ray, and P. Callahan for useful discussions. Altimeter data for this study was obtained from the NASA Physical Oceanography Distributed Active Archive Center (PO.DAAC) at the Jet Propulsion Laboratory/California Institute of Technology. We also thank JPL and G. Kruizinga of the Satellite Geodesy and Geodynamics Group for providing the altimetry database software. S.D. Desai provided the cross-track gradient model. S. Labroue provided TOPEX and Jason SSB models. This work was funded by the U.S. National Aeronautics and Space Administration under a Jason science investigation.