Comparisons among ten models of acoustic backscattering used in aquatic ecosystem research

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2015-12-21
Authors
Jech, J. Michael
Horne, John K.
Chu, Dezhang
Demer, David A.
Francis, David T. I.
Gorska, Natalia
Jones, Benjamin A.
Lavery, Andone C.
Stanton, Timothy K.
Macaulay, Gavin J.
Reeder, D. Benjamin
Sawada, Kouichi
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10.1121/1.4937607
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Abstract
Analytical and numerical scatteringmodels with accompanying digital representations are used increasingly to predict acoustic backscatter by fish and zooplankton in research and ecosystem monitoring applications. Ten such models were applied to targets with simple geometric shapes and parameterized (e.g., size and material properties) to represent biological organisms such as zooplankton and fish, and their predictions of acoustic backscatter were compared to those from exact or approximate analytical models, i.e., benchmarks. These comparisons were made for a sphere, spherical shell, prolate spheroid, and finite cylinder, each with homogeneous composition. For each shape, four target boundary conditions were considered: rigid-fixed, pressure-release, gas-filled, and weakly scattering. Target strength (dB re 1 m2) was calculated as a function of insonifying frequency (f = 12 to 400 kHz) and angle of incidence (θ = 0° to 90°). In general, the numerical models (i.e., boundary- and finite-element) matched the benchmarks over the full range of simulation parameters. While inherent errors associated with the approximate analytical models were illustrated, so were the advantages as they are computationally efficient and in certain cases, outperformed the numerical models under conditions where the numerical models did not converge
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Author Posting. © Acoustical Society of America, 2015. This article is posted here by permission of Acoustical Society of America for personal use, not for redistribution. The definitive version was published in Journal of the Acoustical Society of America 138 (2015); 3742, doi:10.1121/1.4937607.
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Journal of the Acoustical Society of America 138 (2015); 3742
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