RETRIEVAL OF GEOPHYSICAL PARAMETERS FROM RA-2 ENVISAT USING THE SOUTHAMPTON OCEANOGRAPHY CENTRE RETRACKING ALGORITHM

• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Sea ice
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.380.454; http://earth.esa.int/workshops/salzburg04/papers_posters/2A5_gomez_281.pdf

The Southampton Oceanography Centre ocean retracker, initially designed for ERS-1 altimeter data, has been updated for RA-2 Envisat waveform data, in order to be used to retrieve some geophysical parameters such as, the significant wave height, the backscatter power and the range. The algorithm, based on the Maximum Likelihood Estimation, is capable of obtaining those parameters, assuming both linear and non-linear conditions. The use of the non-linear case, allows us to estimate additional parameters, such us the skewness, which relates to the nonlinearity of the wave field (i.e. peakier crests/flatter troughs) and a crossskewness term, with no clear physical significance. In the present work, we have retrieved the significant wave height and the range from RA-2 Envisat 18 Hz waveforms using the SOC ocean retracker. First results show that the linear MLE model retrieves parameters consistent with those in RA-2 SGDR records. This work is part of an ESA study for the exploitation of the Envisat radar altimeter individual echoes and S-band data for ocean, coastal zone, land and ice/sea-ice altimetry (RAIES). 1