Synthesis of the main Features and Evolutions of ESA and CNES/NASA Radar Altimeters, Ocean Ground Processing and Products
Jean-Paul Dumont(1) , Ouan Zan Zanife(1) , Batoula Soussi(1) , Pierre Thibaut(1) , Patrick Vincent(2) , Nicolas Picot(3) , Jérôme Benveniste(4) , and Pierre Femenias(4)
8-10 rue Hermes,
31520 Ramonville Saint-Agne,
(2) IFREMER, 155, rue Jean-Jacques Rousseau, 92138 Issy-les-Moulineaux Cedex, France
(3) CNES, 18 avenue Edouard Belin, 31041 Toulouse Cedex 4, France
(4) ESA/ESRIN EOP-GOQ, Via Galileo Galilei CP64, I-00044 Frascati, Italy
A global and unbroken coverage of the globe is insured for 15 years by radar altimeters, thanks to a series of ESA and CNES/NASA missions (ERS-1 / 1991, TOPEX-Poseidon / 1992, ERS-2 / 1995, Jason-1 / 2001 and ENVISAT / 2002).
On behalf of ESA, CNES or IFREMER, CLS has been in charge of the definition, the specification and the development of the ground processing of the corresponding ESA and CNES altimeters data (ERS-1/2 altimeters, Poseidon-1/2 and RA2) from level 0/1 up to level 2 products. CLS is also in charge of the maintenance of the operational ground processing of ERS-2 altimeter data (IFREMER/CERSAT-2), of RA2 data (ESA/IPF for the NRT ocean processing, CNES/SSALTO-CMA for the off-line processing), of Poseidon-1 data (CNES/RADALT) and of Poseidon-2 data (CNES/SSALTO-CMA).
Thanks to our experiment in altimetry for 20 years, we propose to present a synthesis of the main features and evolutions of ESA and CNES/NASA radar altimeters, ocean ground processing and products. Instrumental features and on-board processing will be compared (e.g. emitted frequencies, operation modes, tracking method). The main functions of the ground ocean processing will be identified and their major evolutions from a mission to another but also within each mission will be presented and discussed (e.g. ocean retracking algorithm, geophysical corrections, environmental parameters, auxiliary data used). Finally, the various kinds of ocean products will be presented and characterised (e.g. type of product, impact of the processing evolutions on their accuracy).