Backscattering Characteristics over a Wide Band of a Sand Bottom in the South Yellow Sea of China

For shallow water environments, reverberation disturbance mainly derives from the bottom scattering. Although acoustic scattering strength is a feature of the bottom, scattering characteristics are different for various sediment types and areas. Backscattering strength at a grazing angel range of 20°–70° over a broad band of 6–24 kHz from a sand bottom in the area of the South Yellow Sea was measured, utilizing a pair of omnidirectional transmitter and hydrophone. The backscattering strength depends on the grazing angle with a positive gradient and performs a faster rate at grazing angle range of 60°–70°. For frequency dependence, the backscattering strength overall enhances with the frequency. Fitting curves of Lambert’s law to the measured data indicate that Lambert’s law departs from the data at grazing angle range of 60°–70°. Fitting curves of a scattering model on the basis of that of Jackson et al. against the data indicate that the seafloor roughness scattering is primary relative to the sediment volume scattering for frequency lower than 10 kHz and at grazing angle range of 60°–90° for high frequency.