Geoacoustic inversion using SA in East China Sea experiment

Matsumoto, Sayuri; Ohta, Kazuaki; Okabe, Kouki; Takei, G.

doi:10.1109/ut.2002.1002437

Cited by 3 publications

(2 citation statements)

References 4 publications

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“…The dependence of the sea surface reflection loss on grazing angle is not taken into account. Bottom reflection loss is calculated using OASES [6] with sound speed and density profiles in the sediment, which are estimated using the result of another sound propagation experiment conducted at a site approximately 37 km southwest away from this experimental site [7]. The sea surface reverberation level is calculated in the same way as the bottom reverberation level.…”

Section: Reverberation Modelmentioning

confidence: 99%

Estimation of sea surface and bottom scattering strengths from measured and modeled reverberation levels

Oikawa

Ohta

Okabe

et al. 2007

Acoust. Sci. & Tech.

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A measurement of low-frequency reverberation was conducted in order to investigate features of sea surface and bottom scatterings in shallow water, where it is generally difficult to acquire sea surface and bottom reverberations separately. In the measurement, a vertical line array receiver is used so that reverberations scattered from the sea surface and bottom over a wide range of grazing angles are captured with multibeams covering a vertical plane. The parameters of the sea surface and bottom scattering functions are estimated by applying the stochastic inversion method to solve the forward problem involving the measured reverberation and its modeling result calculated using the sea surface and bottom scattering functions. The estimated parameters produce a modeling result that is in good agreement with the measured reverberation for each beam, and describe sea surface and bottom scattering strengths as functions of grazing angle via the scattering functions.

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Section: Reverberation Modelmentioning

confidence: 99%

Estimation of sea surface and bottom scattering strengths from measured and modeled reverberation levels

Oikawa

Ohta

Okabe

et al. 2007

Acoust. Sci. & Tech.

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“…A series of experiments were conducted on the continental shelf of the East China Sea from 1999 through 2001 as a part of SWAT (Shallow Water Acoustic Technology) project for studying the shallow water acoustic properties [1,2]. The same kind of experiment was also conducted on the New Jersey continental shelf of the Atlantic Ocean in October 2000 [3,4].…”

Section: Introductionmentioning

confidence: 99%

Inversion for seabed geoacoustic properties in shallow water experiments

Ohta

Okabe

Morishita

et al. 2005

Acoust. Sci. & Tech.

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Low frequency sound propagation features and bottom sediment properties in shallow water were studied in the Shallow Water Acoustic Technology (SWAT) experiments conducted in the East China Sea. In these experiments, a hydraulic-type acoustic source was towed over a range of some 30 km at constant mid-water depth and transmitted low-frequency cw signals, which were received on a bottom-moored vertical line array. After suppressing a time-dependent factor of the received signals, the asymptotic Hankel transform was applied to the acoustic field provided by the resulting synthetic aperture horizontal array that was created at each receiver depth. The horizontal wavenumber spectra thus obtained had peaks corresponding to mode, but these peak positions were observed to be slightly different among the different receiver depths partially due to noise and range dependency. Thus, stochastic mode inversion was exploited by using all of the identified peak positions for estimation of the geoacoustic properties. The sound field simulated using the estimated properties was compared with the measured one for each receiver depth and an excellent agreement was confirmed not only at the frequency used for the inversion but also at the different frequency.

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