Seafloor characterization using time-dependent acoustic backscatter: study at Arabian Sea

Abstract

This paper presents application of "inversion modeling" technique to echo shape data acquired shallow water regions off Goa. The estimated sediment and seafloor roughness parameter for two different frequencies (33 and 210 kHz) provide comparable results. The mean grain size of the sediment (М <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ϕ</sub> ) estimated through the inversion of echo envelope data deviates for mixed sediments of clayey-silt type of five locations for both the operating frequencies, though the roughness characteristics (ω <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ) and volume characteristics (σ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">v</sub> ) show a good agreement for relatively mixed and coarse-grained sediments. The extent of deviation in estimated grain size parameters can be related well the estimated sediment volume roughness parameters. Location wise higher sediment volume inhomogeneities in turn show difference in the estimated mean grain size (interface roughness) parameter for five mixed sediment type (clayey-silt).