GEOMETRICAL RAY-BUNDLE REVERBERATION MODELING

The classical ray approach for monostatic ocean boundary reverberation has been re-examined based on a geometrical ray-bundle concept. In this new formulation, the impulse response for the averaged scattering intensity is expressed by a simple function consisting of continuous ray-bundle quantities with respect to the time, and which can be regarded as a generalized function for ray-based reverberation in a boundary cell. To numerically evaluate this impulse response, a zeroth- and a first-order polynomial interpolation method are respectively applied to approximate the ray-bundle quantities. Then, the impulse function is reduced to the forms of the delta function and the rectangular function either with or without linear amplitude modulation linear in time. These basic functions are used to develop an explicit numerical scheme for the monostatic reverberation, which originates in the split-step marching algorithm for the range. This numerical scheme provides a considerable accuracy even with larger range steps and gives reasonable results for numerical examples of ocean waveguides with isovelocity, summer, and winter sound-speed profiles.