Using Ambient Noise to Inverse Geo-Acoustic Parameters

This paper presents a theoretical study of the vertical coherence of ocean ambient noise as the source is the windy ocean surface on the ray theory. At low frequencies less than 2 kHz, the sensitivity of stratified fluid seabed to the vertical coherence of ambient noise in shallow water is analyzed under the condition of distance-irrespective stratified ocean. Using ambient noise data from Chinese north shallow water seabed geo-acoustics parameters are obtained, and the research results show that the inverted method is effective.

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Effect of Guide’s Acoustic Parameters on Vertical Directivity of the Marine Ambient Noise

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.577.1207 ◽

2014 ◽

Vol 577 ◽

pp. 1207-1210

Author(s):

Chun Xia Meng ◽

Hao Mu ◽

Gui Juan Li

Keyword(s):

Shallow Water ◽

Sound Speed ◽

Ambient Noise ◽

Sound Propagation ◽

Sea Water ◽

Surface Boundary ◽

Ray Theory ◽

Directivity Characteristic ◽

Acoustic Parameters ◽

Equipment Performance

The vertical directivity characteristic of ambient noise is one inherent characteristic of the ocean in shallow water. And it includes the information of guide’s acoustic characteristic information. The marine guide is composed of sea water; seabed and surface boundary, there into, the acoustic parameters of seabed are hardly obtained exactly. In this paper, the model of vertical directivity for ambient noise is established. Based on the ray theory of sound propagation, the influence of guide’s acoustic parameters which include sound speed, density and attenuation coefficient on vertical directivity of marine ambient noise is simulated. The results are propitious to analysis and command the characteristics of ambient noise, and valuable to accelerate the exertion of acoustic equipment performance.

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Geo-Acoustic Parameters Inversion from Vertical Coherence Characteristic of Ambient Noise

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.385-386.567 ◽

2013 ◽

Vol 385-386 ◽

pp. 567-570

Author(s):

Chun Xia Meng ◽

Gui Juan Li ◽

Liang Zhang

Keyword(s):

Shallow Water ◽

Acoustic Field ◽

Relative Stability ◽

Ambient Noise ◽

Frequency Range ◽

Shallow Sea ◽

Acoustic Parameters ◽

Different Seasons ◽

Noise Data ◽

Parameters Inversion

In shallow sea the wave of ambient noise contains the information of environment acoustic field. In theory, vertical coherence, which is one of the numerous ambient noise field characters, can be used to invert geo-acoustic parameters because of its relative stability. The ambient noise data were collected in two different seasons using two vertical-laid hydrophones in shallow water. Then acoustic parameters of semi-infinite space seabed are inversed from the vertical coherence of measured ambient noise in the frequency range of 100Hz~3 kHz. The predicted vertical coherence curve of ambient noise, which is computed using inversed parameters, agrees with the measured curve by comparison. The experiment results show that geo-acoustic parameters can be inversed effectively by the vertical coherence of ambient noise.

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