Phys. Dept., Ocean Univ. of Qingdao, Qingdao 266003, People's Republic of China
R. Kind's method of calculation was adopted in dealing with the reflected coefficient spectrum from layers of nonuniform plane waves. With measurements of temperature, salinity, and depth at the Southern Yellow Sea in China, data of simulated scattering signals were obtained. Compared with what the scattering signals were measured, it was proven that the mechanism of sound scattering was mainly dependent on the nonuniformity of temperature in the shallow sea. According to the magnitude of sea waves and the parameter of plankton distribution, it is possible to expound the fluctuation of sound scattering signals affecting by the ocean circumstance. The influence of the distribution of plankton density was merged as a background noise in it. The results showed that the primary factors of interference were the wind waves and swells. Under a second degree ocean condition, the variance of the arrived times of scattering signals is about 0.2 ms. In the case of a third ocean condition, the variance of the arrived times of scattering signals is 3.5 ms due to the wind wave and 1.5 ms due to the swell.