Numerical modeling in the problem of the mechanisms of SAR imaging of the ocean

Based on numerical modeling, we demonstrate the validity of the conclusion, drawn on the basis of theoretical analysis in [1], that the mechanism of fluctuations of the effective density of scatterers, which is commonly accepted at present as the physical basis for the space-borne SAR diagnostics of the ocean surface, actually works only in the case of a sufficiently flat swell in the absence of wind roughness. In all other cases, the dominant role is played by another mechanism, namely, fluctuations of the number of surface elements whose images are randomly shifted and superimposed due to orbital velocities. The special consideration is devoted to the case of mixed roughness comprising both wind roughness and swell. It is shown that, in contrast to long-wavelength narrow-band swell in the absence of large wind waves, the same swell in the mixed roughness is revealed in the linear manner in an SAR image.