Long-range propagation of finite-amplitude acoustic waves in an ocean waveguide

A hybrid method coupling nonlinear and linear propagation codes is used to study the nonlinear signature of long-range acoustic propagation for high-amplitude sources in an ocean waveguide. The differences between linear and nonlinear propagation are investigated in deep and shallow water environments. The spectral reshaping that occurs in nonlinear propagation induces two main effects: in shallow water, an unusual arrival time structure in the lowest order modes is observed, and in both shallow and deep water environments, there is a tendency to have acoustic energy more uniformly distributed across modes. Further, parametric low-frequency generation in deep water is a candidate for the coupling between water and sediments for T-wave formation. (C) 2004 Acoustical Society of America.