THEORETICAL ADVANCES IN PROPAGATION THROUGH A FLUCTUATING OCEAN WAVEGUIDE WITH RANDOM 3-D IN- HOMOGENEITIES

Recently a new fundamental theory has been developed from which closed form analytic expressions have been obtained for the mean and covariance of the acoustic field forward propagated through a fluctuating ocean waveguide with random 3-D inhomogeneities, such as internal waves, eddies, ocean turbulence, fish and bubbles. The expressions include the effects of multiple forward 3-D scattering, mode coupling, attenuation and dispersion. This approach has been applied to solve a number of outstanding ocean acoustics problems in both continental shelf and deep ocean waveguide environments. This includes determination of the attenuation and dispersion due to 3-D scattering from internal waves as a function of frequency, range and internal wave energy, the relative contribution of coherent versus incoherent field components, and spatial coherence for array processing. The temporal coherence and coherence time scales of acoustic propagation through a fluctuating ocean as a function of internal wave energy and range have also been determined with closed form analytic expressions. These developments make it possible to design experiments and make accurate performance predictions in many practical ocean acoustic sensing scenarios.