ABSTRACT

This chapter proposed a joint method to retrieve directional ocean wave spectra from synthetic aperture radar and real aperture radar (RAR). The method broke through the limitations existed in the single-sensor wave retrieval, by combining two sensors’ characteristics. First, the Hs was estimated from the SAR cutoff using an empirical model. On the other hand, the relative wave spectra at large scale was derived from the RAR modulation spectra. After that, the first guess spectra were estimated by relative wave spectra and SAR-derived Hs. Finally, the full wave spectra at small scale were retrieved from the SAR image cross spectra with the help of first guess spectra using the Max-Planck-Institute scheme. The 180° ambiguity of retrieved wave spectra was removed using the imaginary part of SAR cross spectra. Both simulation and collocated data were used to validate the joint method. This method helps to complement traditional wave retrieval methods.