Comparative study of electromagnetic scattering from two-dimensional linear and nonlinear sea surfaces

The two-dimensional linear and nonlinear sea surface models combined with the first-order small slope approximation (SSA) method are used to comparatively study the statistical properties of the two surfaces and their radar electromagnetic scattering characteristics. Computational results show that the nonlinear waves have sharper wave crests and shallower troughs than those of the corresponding linear waves. The root mean square of height remains unchanged, but the slopes are increased and depart from the Gaussian distribution. As a consequence, the bistatic normalized radar cross section (NRCS) calculated from nonlinear surfaces is slightly larger than its linear surface counterpart for the scattering angles departing from the specular direction, and the nonlinear surface backscattering coefficient increases. This discrepancy becomes greater for small depression angles.