Bottom scatter strength—the fraction of incident acoustic energy scattered nonspecularly from the rough ocean bottom—can significantly affect the performance of underwater acoustic systems in bottom-limited environments. Despite this, bottom scatter strength is one of the lesser understood inputs to underwater acoustic propagation models, and the lack of high-quality bottom scatter data often results in the application of coarse rules-of-thumb (e.g. Mackenzie model with μ = –27 dB). In this presentation, an approach to characterizing local bottom scatter strength is presented that utilizes a vertical glider array and an acoustic projector towed from a surface vessel repeating a spread-spectrum (2–4 kHz) waveform. Spatial beamforming and matched filtering are used to separate and identify the unique acoustic paths from source to receiver. This allows for the isolation of nonspecular scattered energy from the bottom-interacting paths as a function of angle and arrival-time. These distributions of received energy are then visually and quantitatively compared against a simple geometric model and used to estimate the parameters of a generalized Lambert bottom scatter kernel. Results are shown for a region near the New England Shelf Break, and comparisons are made against results from previous independent surveys.
Flynn et al. (Wed,) studied this question.