Acoustic Scattering From Rough Sea Surface

Acoustic scattering from the 1-D rough surface by the small slope approximation theory is studied, and the scattering strength of the rough sea surfaces which has a Gaussian spectrum is derived. The change of the scattering strength with the rms surface slope, frequency, velocity of sound propagation, incident angle and scattering angle is discussed by means of computer simulation. The results by the small slope approximation are also compared with the integral equation method, and show that the small slope approximation is an efficient method to solve the problem about acoustic scattering from the rough surface.Acoustic scattering from the 2-D rough surface by the small slope approximation theory is also studied, and the scattering strength of the rough sea surfaces which has a modified power-law spectrum is derived. The change of the scattering strength with the power-law parameter, frequency, velocity of sound propagation, wind speed, incident angle, scattering angle and bistatic angle is analyzed by means of computer simulation. The results of the small slope approximation are consistent with the experiment.In the experiment fans at different position are used to obtain the rough sea surface. And the rough sea surface's spatial power spectrum density is obtained with the method of periodogram method. The horizontal spatial power spectrum density is compared with the vertical spatial power spectrum density, and show that the rough sea surface is isotropic. In order to eliminate the direct signal and the scatters at the fixed position scattering signals from the rough surface scattering signal, a spatial domain processing method was introduced.