Investigation of Acoustic Wavefield Dynamics in Quasi-Realistic Ocean Environments

Our long-term goal is to provide a more complete understanding of the forward propagation of acoustic pulses in range dependent deep ocean environments at multi-megameter range scales. OBJECTIVES The objective is to understand the limits of wavefield predictability in ocean environments where refractive scattering is the dominant physical process controlling the dynamics of the wavefield. The canonical scenario is long range acoustic transmissions along the ocean waveguide which has sound speed fluctuations due to oceanic processes characterized by linear Rossby waves and internal waves. The work on this project to date has focused on ocean environments that include the former. APPROACH The technical approach involved the development of a three dimensional ocean acoustic ray trace numerical model associated with the solution of the one-way Helmoltz equation. The boundary conditions are specular reflection at the surface, open in the horizontal, and open on the bottom. A Cartesian coordinate system is used, and no account is taken for the sphericity of the Earth. A Hamiltonian prescription is facilitated, and besides the standard ray quantities (i.e. depth, crossrange, vertical momentum, horizontal momentum, and travel time), the model also solves for the elements o