Integrating the energy flux method for reverberation with physics-based seabed scattering models: modeling and inversion.

During the past 30 years, one of the major accomplishments in ocean acoustics is the improvement of understanding seabed scattering, resulting from a significant effort of both at-sea measurement and theoretical modeling. [Jackson and Richardson: High-Frequency Seafloor Acoustics, 2007]. Benefiting from this accomplishment, this paper integrates the energy flux method for shallow-water (SW) reverberation [Zhou, (Chinese) Acta Acust. 5, 86-99 (1980)] with the physics-based seabed scattering models. This integration directly and intuitively results in general expressions for SW reverberation in the angular and modal domains. The latter expression is the same as the modal reverberation expression derived from the Green's function and boundary perturbation method by Tracey and Schmidt [IEEE J. Ocean. Eng. 22, 317-331(1997)]. The integration also results in a simple relationship between the classic boundary scattering cross sections and the modal scattering matrix in SW waveguides. The bottom roughness spectrum and sediment volume scattering cross section at low grazing angles are inverted in a frequency range of 150-2500 Hz from the wideband long-range reverberation data by using the Biot seabed geoacoustic model. The results may offer some reference data sets for future analysis of the low-frequency seabed scattering mechanisms. (C) 2013 Acoustical Society of America.