LONG-RANGE REVERBERATION AND BOTTOM SCATTERING STRENGTH IN SHALLOW WATER

According to the method of angular power spectrum for average sound field in shallow water, the transformation relation between arbitrary angle dependence of bottom scattering and the range dependence of long-range reverberation in shallow water homogeneous layer is established. As compared with the conventional model of boundary reverberation at short-range in deep sea, a multipath factor will be added. By using the transformation relation, the bottom baekscattering strength for the frequency band of 0.8-4.0 kHz and grazing angle range of 2-10 has been derived from shallow-water reverberation data at five locations in the Yellow Sea, the Bohai Sea and the East China Sea. It is shown that the bottom scattering constant (u) and angle index (2n) for high speed sediment of continental shelf depend not only on sea area and frequency, but also on angle range. For very low grazing angle the decay of bottom baekscattering strength with decreasing grazing angle is. more rapid than that for mediate grazing angle.