Propagation of Low-Frequency, Transient Acoustic Signals through a Fluctuating Ocean: Development of a 3D Scattering Theory and Comparison with NPAL Experimental Data

Development of a new, 3D, modal theory of low-frequency, long-range sound propagation through a fluctuating ocean, including both CW and transient acoustic signals. Comparison of theoretical predictions with NPAL experimental data. OBJECTIVES To develop a 3D modal theory of broadband sound propagation though a fluctuating ocean, including analysis of the coherence function for transient acoustic signals and temporal coherence. To develop computer codes for calculation of the horizontal and vertical coherence functions of transient acoustic signals and temporal coherence. APPROACH Coherence of low-frequency sound waves propagating in the ocean diminishes due to sound scattering by internal waves (IWs), spice, and other ocean processes. Therefore, studies of statistical characteristics of low-frequency sound waves propagating through a fluctuating ocean are important for many practical applications, e.g., underwater communication and assessment of performance of