Chapter 2
RA2/MWR Products and Algorithms

2.1 Introduction

In section 2, the RA-2/MWR data products and the algorithms developed to compute the main parameters in the products are described.

Based on the experience from the ERS missions, significant improvements have been built into this new generation of altimetric products, particularly in terms of the enhanced quality of the near-real-time observations, which will be almost as accurate as the final precise product. The product-specification process has included wide consultation with users of ERS and Topex/Poseidon altimetric data. Further product refinement and state-of-the- art algorithm specification were conducted with the help of three European Expert Support Laboratories (ESLs): Alenia Aerospazio (I), Collecte Localisation Satellites (F) and Mullard Space Science Laboratory (UK).

The algorithm specifications were validated by prototyping within the ESL. Once verified, ESL prototypes became reference processors to produce test data sets designed to validate the ground-segment Instrument-data Processing Facility (IPF). Moreover, the RA-2 and MWR products and algorithms were peer-reviewed by dedicated experts and were the subject of an open review at the Envisat Altimetry Products and Algorithms Review Workshop held at ESRIN in Frascati in June 1999.

The EnviSat RA-2 and MWR Data Products will have - already available in near-real-time - global coverage, the wet tropospheric correction from the microwave radiometer and the ionospheric correction from the two frequencies, as well as many other improvements coming from the novel design of second-generation Radar Altimeter. The comprehensive near-real-time processing runs the same algorithms as for the offline products, with only the availability and quality of the auxiliary data differing.