title: Comparisons among ten models of acoustic backscattering used in aquatic ecosystem research.
abstract: Analytical and numerical scattering models 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 m(2)) 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.
authors.affiliation: Northeast Fisheries Science Center, 166 Water Street, Woods Hole, Massachusetts 02543, USA.
authors.forename: J Michael
authors.initials: JM
authors.lastname: Jech
authors.affiliation: School of Aquatic and Fishery Sciences, University of Washington, Box 355020, Seattle, Washington 98195, USA.
authors.forename: John K
authors.initials: JK
authors.lastname: Horne
authors.affiliation: Northwest Fisheries Science Center, 2725 Montlake Boulevard East, Seattle, Washington 98112, USA.
authors.forename: Dezhang
authors.initials: D
authors.lastname: Chu
authors.affiliation: Southwest Fisheries Science Center, 8604 La Jolla Shores Drive, La Jolla, California 92037, USA.
authors.forename: David A
authors.initials: DA
authors.lastname: Demer
authors.affiliation: School of Electronic, Electrical and Systems Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom.
authors.forename: David T I
authors.initials: DT
authors.lastname: Francis
authors.affiliation: Institute of Oceanography, University of Gdansk, Aleja Marszlka Pilsudskiego 46, 81-378 Gdynia, Poland.
authors.forename: Natalia
authors.initials: N
authors.lastname: Gorska
authors.affiliation: Oceanography Department, Graduate School of Engineering and Applied Sciences, Naval Postgraduate School, Monterey, California 93943, USA.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Jones
authors.affiliation: Department of Applied Ocean Physics and Engineering, Woods Hole Oceanographic Institute, Woods Hole, Massachusetts 02543, USA.
authors.forename: Andone C
authors.initials: AC
authors.lastname: Lavery
authors.affiliation: Department of Applied Ocean Physics and Engineering, Woods Hole Oceanographic Institute, Woods Hole, Massachusetts 02543, USA.
authors.forename: Timothy K
authors.initials: TK
authors.lastname: Stanton
authors.affiliation: National Institute of Water and Atmospheric Research, Private Bag 14901, Kilbirnie, Wellington 6021, New Zealand.
authors.forename: Gavin J
authors.initials: GJ
authors.lastname: Macaulay
authors.affiliation: Naval Postgraduate School, Monterey, California 93943, USA.
authors.forename: D Benjamin
authors.initials: DB
authors.lastname: Reeder
authors.affiliation: National Research Institute of Fisheries Engineering, Fisheries Research Agency, 7620-7, Hasaki, Kamisu, Ibaraki 314-0408, Japan.
authors.forename: Kouichi
authors.initials: K
authors.lastname: Sawada
mesh_terms: D000162:Acoustics; D000818:Animals; D003198:Computer Simulation; D017753:Ecosystem; D020342:Finite Element Analysis; D005399:Fishes; D008962:Models, Theoretical; D009038:Motion; D009716:Numerical Analysis, Computer-Assisted; D012542:Scattering, Radiation; D013016:Sound; D013997:Time Factors; D014867:Water; D015048:Zooplankton
chemical_list: D014867:Water