Naval Res. Lab., Washington, DC 20375-5350
Scattering from a target in a bounded medium involves both propagation effects and target scattering effects as well as the coupling of the two. Previously, in order to simply the problem, the coupling of the two effects had been neglected by ignoring the contribution of multiple scattering between target and shallow water boundaries. This has been highly desirable because it eliminates the need to evaluate the shallow water Green's function over short ranges. Scattering computations are made to show the importance of including this coupling effect even at relatively low frequencies. It is shown that if the target is closer to the surface than the bottom, then the main contribution of the multiple scattering is due to the interaction of the target with the top surface and this effect may easily be included when the method of superposition is applied.