Observations of the R reflector and sediment interface reflection at the Shallow Water ’06 Central Site

Choi, Jee Woong; Dahl, Peter H.; Goff, John A.

doi:10.1121/1.2963048

Cited by 32 publications

(34 citation statements)

References 17 publications

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“…Choi et al 7 analyzed close range high frequency (1-20 kHz) bottom loss data from the same site, and inferred the attenuation from a very thin surficial sediment layer from inversions of the measured loss. They found that a frequency dependence of 0.2͑f / f ref ͒…”

Section: Resultsmentioning

confidence: 99%

Estimating marine sediment attenuation at low frequency with a vertical line array

Jiang

Chapman

Yang

et al. 2009

The Journal of the Acoustical Society of America

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This paper presents a method of determining the compressional wave attenuation in marine sediment from a short range measurement. The data were collected on a vertical line array at a range of 230 m during the Shallow Water 2006 experiments. The sediment attenuation is extracted from the signal strength ratio of the sea bottom reflection to a sub-bottom reflection at different frequencies from 1.75 to 3.15 kHz. Linear frequency dependence of the attenuation is found from the estimation. The sediment attenuation estimate is lower than the values estimated from the inversions of acoustic field data previously done in the vicinity.

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Section: Resultsmentioning

confidence: 99%

Estimating marine sediment attenuation at low frequency with a vertical line array

Jiang

Chapman

Yang

et al. 2009

The Journal of the Acoustical Society of America

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“…• Waveform and bottom loss matching (Choi et al 2008) • Matched field inversion • Matched field inversion (Huang et al, 2008) • Wavenumber extraction inversion (Ballard et al, 2010).…”

Section: Work Completedmentioning

confidence: 99%

Geoacoustic Inversion in Shallow Water

Chapman¹

2012

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Award Number: N00014-11-1-0057 / Shallow-water acoustics LONG TERM GOALSThe ability to predict the sound field in shallow water is constrained by the knowledge of the geoacoustic properties of the bottom. The long term objectives of this research project are related to the investigation of experimental methods and inversion techniques for estimating parameters of geoacoustic models of the ocean bottom and the associated uncertainties in the model parameter values. The specific goals are to evaluate the performance of geoacoustic inversion techniques that have been developed for use in range-dependent shallow water environments, and synthesize the results obtained for characterizing the seabed from the SW06 and other recent experiments. The wider context of this research is to achieve improved sonar system performance through greater understanding of the physics of the interaction of sound with the ocean bottom. OBJECTIVESThere are two objectives in this research report. The first is to compare the performance of geoacoustic inversion methods that have been developed for estimating geoacoustic models from acoustic field data. The inversion performance has been assessed previously in ONR Benchmarking workshops (Tolstoy et al., 1998;Chapman et al., 2003) that used simulated acoustic fields for several candidate shallow water waveguide environments. The hypothesis in this work is that data from the ONR SW06 experiment can serve as an experimental benchmark for assessing inversion performance against real data. This report compares the performance of geoacoustic inversion methods that were used to estimate parameters of geoacoustic profiles in SW06. These include matched field inversion, reflection coefficient and bottom loss inversion, and wavenumber extraction inversion.A critical issue in the many of the inversion methods is the impact of uncertainty in the knowledge of the ocean environment and the experimental geometry on inversion performance. A second objective in this work is to investigate approaches for estimating geoacoustic model parameters that are robust to environmental and experimental uncertainty. APPROACHThe research makes use of data recorded from different experiments in the vicinity of the MORAY site shown in Figure 1 (Yang et al., 2008). This area of outer shelf wedge sediments (Goff et al., 2004)

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“…및 음속, 감쇄계수 역산, [1] 다층 구조 퇴적층에서 수 신된 반사 손실을 이용한 퇴적층의 두께 및 지음향 인자 역산, [2] 해양에 존재하는 주변 소음의 수신 위 상 정보를 이용한 하부 퇴적층 구조 역산 [3] 에서 제 공받은 평균입도자료를 이용하여 계산되었다.…”

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Estimation of surficial sediment thickness using mid-frequency ocean acoustic bottom reflected signals measured in shallow water off Geoje island

KwonHyuckJong¹,

Son²,

Cho³

et al. 2016

The Journal of the Acoustical Society of Korea

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Measurements of bottom loss as a function of grazing angle (in range of 9~14°) at a frequency range of 4~8 kHz were conducted on an experimental site off Geoje island in October 2015. Geoacoustic inversion of the surficial sediment thickness is performed using the arrival time difference between the surficial layer and the sub-bottom layer reflected signal. To invert the thickness of surficial sediment, we used the grain size of 8~10 ϕ obtained by KIGAM (Korea Institute of Geoscience and Mineral Resources). The thickness of the surficial sediment was estimated to be 4~7 m. Finally, this inversion result was compared with the geoacoustic observation conducted by the KIOST (Korea Institute of Ocean Science & Technology) using sub-bottom profiler.

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Observations of the R reflector and sediment interface reflection at the Shallow Water ’06 Central Site

Cited by 32 publications

References 17 publications

Estimating marine sediment attenuation at low frequency with a vertical line array

Estimating marine sediment attenuation at low frequency with a vertical line array

Geoacoustic Inversion in Shallow Water

Estimation of surficial sediment thickness using mid-frequency ocean acoustic bottom reflected signals measured in shallow water off Geoje island

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