Effects of Roughness Scale on Ocean Radar Scattering Using Numerical Simulations

We employ the second-order small slope approximation (SSA-II) and the method of moment (MoM) to investigate the roughness scale effect on ocean radar scattering in both three- (3-D) and two-dimensional (2-D) cases. Various roughness scales of the ocean surface are represented by truncating the Kudryavtsev wave spectrum. Criteria of full spectrum truncation are proposed for the numerical simulations of ocean scattering. Numerical results are illustrated in fully bistatic configuration at L- and C- bands. It is found that short waves with wavenumber larger than 316 rad/m have little effects on ocean scattering. The large-scale waves put more effects on scattering in the forward directions, particularly for large incidence angles. For numerical simulations of ocean scattering with incidence angle less than 60°, using small surface profiles with size about 1/6 of those accounting for full spectrum yields result with errors less than 2dB.