SEARCHING FOR SHADOW ZONES AND COMMUNICATING AND IMAGING IN THE OCEANIC ACOUSTIC WAVE GUIDE

摘要

We apply new mathematical and numerical techniques for studying the propagation of acoustic waves in the oceanic wave-guide. In its simplest form the approach solves exactly the parabolic wave equation for a given acoustic field based upon sound speed profiles over a well-defined range, say those obtained by AXBTs. The well-known standard numerical approaches propagate the acoustic field using, for example, the fast Fourier transform [Hardin and Tappert, 1973]. The approach has several advantages over other approaches for studying the PE: (a) It provides the exact solution of the PE by using multi-dimensional Fourier analysis, (b) it provides a new and important physical interpretation of the nonlinear modes in the acoustic field, (c) it provides new approaches for the time series analysis and interpretation of acoustic data and (d) it provides for new numerical codes which are "hyper fast" with respect to the well known fast Fourier transform solutions of the PE.