Modeling of Microwave Backscattering from a Rough Sea Surface with Steep Waves

Traditionally, Kuand C-band radars are used in ocean scatterometry to retrieve an ocean wind vector. Examples are QuikSCAT and ASCAT satellites. Recently, attempts have been made to use X-band SAR aboard the German TerraSAR-X satellite for the same purpose [1]. Usually, wind retrieval is performed using empirical Geophysical Model Functions (GMF). In the past, a set of GMFs have been designed based on data sets obtained in calibration missions with Kuand C-band radars. In the paper [1] the development of a GMF for X-band has been reported, which was utilized to retrieve ocean surface wind speeds from TerraSAR-X. In order to better design the GMFs, use of physical models for radar ocean scattering can be helpful. Previously, such a model was successfully developed for Kuand C-band. The mismatch between the model predictions and GMFs was of the order of 1-2 dB [2]. Here, we present results produced by this model for normalized radar cross section (NRCS) from ocean surface at X-band and provide comparisons with cross sections at Kuand C-bands.