Abstract:
Pulse propagation from a wideband source in the ocean sound channel is being modeled theoretically and numerically in the time domain for comparison with ATOC transmissions on a 3-Mm path between California and Hawaii. The physics of pulse dispersion in a waveguide is addressed using stationary phase approximations for integrals over frequency. For a parabolic sound slowness profile the basic theory admits a closed analytic solution for an impulsive source using the WKB approximation. Inclusion of realistic SSPs with time- and range-dependent fluctuations (primarily internal waves) is accomplished by a combination of parabolic equation modeling and modal analysis. Attempts to include realistic fluctuations in the stationary phase approximation are discussed. [Work supported by NRL and ONR and by the Strategic Environmental Research and Development Program through ARPA.]