The sound propagation in shallow water is greatly influenced by the acoustic properties of seabed. An anomalous transmission loss was observed in an experiment, and a range dependent bottom model with horizontal variation of seabed acoustic property is proposed and could be well used to explain the anomalous phenomena. It is shown that the horizontal variation of bottom properties has a great effect on underwater sound propagation, and it should be given much attention in sound propagation and geoacoustic inversion problems.
The in-plane bistatic backward scattering caused by seabottom with random inhomogeneities and rough interface is studied. This work combines the ray tube integral method of Ivakin et al. and the complex-ray/steepest descent method of Hines. For a given incident grazing angle, the theoretical expression can easily be used to calculate scattering strength for different backward scattering angles. (This is essential for modeling shallow water reverberation by the normal mode approach.) The model is tested against published scattering measurements. The frequency/angle dependence of backward scattering and effects of volume inhomogeneity parameters on backward scattering are also discussed.
PENG Zhaohui1,,ZHOU Jixun1,& ZHANG Renhe1 2 2 1.Institute of Acoustics,Chinese Academy of Sciences,Beijing 100080,China
