SAR Cross-Spectral Analysis of Radial Intermediate Waves: Directional Properties

The ability of Synthetic Aperture Radar (SAR) to observe two-dimensional ocean wave spectra is restrained by both nonlinear imaging and spatial resolution. The improvement of SAR spatial resolution allows us to investigate the properties of intermediate ocean waves. In this study, a new complex parameter focusing on intermediate ocean waves is defined based on SAR image cross-spectra to describe their statistical characteristics. It includes both the magnitude and directional information of intermediate ocean waves. At first order, they are found to be associated to wind speed and wind direction, respectively. The preliminary results show that imaginary part of this parameter exhibits approximately a linear relationship with radial wind speed. The global map of this parameter further confirms its correlation with surface winds, which is potential to better restrain the wind retrieval over one SAR imagette.