Walter Smith (NOAA, USA); Marcello Passaro (Technical University of Munich, Germany)

The standard retracking of Jason-2 and Jason-3 data uses the Maximum Likelihood Estimator to fit 4 geophysical parameters at once: range, significant wave height (Hs), normalized backscatter strength (sigma0) and mispointing. However Rayleigh noise, which is an inherent property of the system will affect the estimation, with correlated induced errors in the 4 parameters, which are clearly visible in the 20 estimates within each 1-second record. Here we update work on the correction of sigma0 values for apparent mispointing, showing how the factor varies with sea state conditions. Previous work on ERS-1 had shown the cross-talk between estimates of range and wave height; these are detailed more fully for the Jason instruments. We draw conclusions on the accuracy of sea level retrievals from such retrackers, and especially on the spectral representation at high wavenumber.