Jason-2 Global Statistical Assessment and Cross-Calibration with Jason-1

Abstract

OSTM/Jason-2 (Ocean Surface Topography mission, named Jason-2 in this paper) satellite was successfully launched on June 20, 2008, and was put on its nominal orbit on July 4, 2008. Up to January 26, 2009, Jason-2 was flying in formation with Jason-1 only 55 seconds apart before Jason-1 was moved to its new interleaved orbit. The objectives of this paper are to assess Jason-2 data quality and to estimate the altimetry system performance from the beginning of the mission, using Geophysical Data Records (GDRs) products. Our study will focus on Jason-1/Jason-2 cross-calibration using the opportunity that the missions were on the same ground track separated by 55 seconds during the formation flight phase. This allows us to precisely assess parameter discrepancies and Sea Surface Height (SSH) consistency between both missions in order to detect geographically correlated biases, jumps or drifts. From the results presented in this paper, it is demonstrated that the Jason-2 mission fulfils the requirements of high precision altimetry, which is crucial for future oceanographic studies and applications. In particular, it allows continuation of the observation of the Mean Sea Level (MSL) variations at the same (or better) accuracy as Jason-1 and TOPEX/Poseidon, which was one of the challenges of the Jason-2 mission. Potential improvements and open issues are also identified, with the objective of still making progress in terms of altimetry data quality.

Keywords:

• altimetry
• calibration/validation
• sea level
• mean sea level

Acknowledgements

This work has been supported by the Centre National d’Etudes Spatiales (CNES) in the frame of the SALP project. We thus gratefully acknowledge the CNES Jason-2 project team, as well as others partners (JPL, EUMETSAT, NOAA) for fruitful discussions and extensive collaborative work.