Assessment of the Jason-2 Extension to the TOPEX/Poseidon, Jason-1 Sea-Surface Height Time Series for Global Mean Sea Level Monitoring

Abstract

The Jason-2 (OSTM) follow-on mission to Jason-1 provides for the continuation of global and regional mean sea level estimates along the ground-track of the initial phase of the TOPEX/Poseidon mission. During the first several months, Jason-1 and Jason-2 flew in formation separated by only 55 seconds, enabling the isolation of inter-mission instrument biases through direct collinear differencing of near simultaneous observations. The Jason-2 Ku-band range bias with respect to Jason-1 is estimated to be −84 ± 9 mm, based on the orbit altitudes provided on the Geophysical Data Records. Modest improved agreement is achieved with the GSFC replacement orbits, which further enables the isolation of subtle (<1 cm) instrument-dependent range correction biases. Inter-mission bias estimates are confirmed with an independent assessment from comparisons to a 64-station tide-gauge network, also providing an estimate of the stability of the 17-year time series to be less than 0.1 mm/yr ± 0.4 mm/yr. The global mean sea level derived from the multi-mission altimeter sea-surface height record from January 1993 through September 2009 is 3.3 ± 0.4 mm/yr. Recent trends over the period from 2004 through 2008 are smaller and estimated to be 2.0 ± 0.4 mm/yr.

Keywords:

• Jason-2
• satellite altimetry
• calibration
• verification
• mean sea level

Acknowledgments

We acknowledge the JPL PODAAC for providing T/P and Jason-1 GDR data, and the AVHRR SST data, and CNES AVISO for the OSTM GDR data. We thank Nicolas Picot and Remko Scharroo for providing Jason-1 GDR_B correction tables prior to the version C release. Foremost the authors are honored to have been able to make a contribution to this special issue dedicated to the memory of Yves Ménard. This work was supported by the U.S. National Aeronautics and Space Administration under the auspices of the Ocean Surface Topography Science Team, the IDS Program in Mean Sea Level, and the MEaSUREs program.