Directional ocean wave spectra extracted from the dual-polarization SAR imagery

A new method is proposed to extract the directional ocean wave spectra from the dual-polarization SAR imagery. Firstly, a new SAR - ocean transform is constructed by combining the quasi-linear transforms of the dual-polarization image spectra and cross spectra. The modulation transfer function (MTF) of the transform depends only on the tilt MTF. The uncertainty of MTFs in hydrodynamic and velocity bunching modulation can't bring extra errors. Secondly, the 180 degrees ambiguity of wave spectra is removed by the imaginary part of dual-polarization cross spectra. Finally, Radarsat-2 quad-polarization SAR imagery was collected to validate the performance. The extracted wave parameters are compared with the ones from buoy. Comparisons preliminarily show the potential of wave spectra extraction from dual-polarization SAR imagery. More cases will be studied.