scholarly journals Geoacoustic inversion for acoustic parameters of sediment layer with low sound speed

2019 ◽  
Vol 68 (9) ◽  
pp. 094301
Author(s):  
Meng-Zhu Li ◽  
Zheng-Lin Li ◽  
Ji-Xun Zhou ◽  
Ren-He Zhang
Keyword(s):  
Sound Speed ◽  
Sediment Layer ◽  
Acoustic Parameters ◽  
Geoacoustic Inversion

scholarly journals Effect of ocean sound speed uncertainty on matched-field geoacoustic inversion

2008 ◽  
Vol 123 (6) ◽  
pp. EL162-EL168 ◽  
Author(s):  
Chen-Fen Huang ◽  
Peter Gerstoft ◽  
William S. Hodgkiss
Keyword(s):  
Sound Speed ◽  
Geoacoustic Inversion

scholarly journals A Volunteer Computing Project for Solving Geoacoustic Inversion Problems

2017 ◽  
Vol 7 (1) ◽  
pp. 363-370
Author(s):  
Oleg Zaikin ◽  
Pavel Petrov ◽  
Mikhail Posypkin ◽  
Vadim Bulavintsev ◽  
Ilya Kurochkin
Keyword(s):  
Inverse Problems ◽  
Shallow Water ◽  
Sound Speed ◽  
Underwater Acoustics ◽  
Volunteer Computing ◽  
Speed Profile ◽  
Geoacoustic Inversion ◽  
Sound Speed Profile ◽  
Profile Reconstruction ◽  
Discretization Grid

AbstractA volunteer computing project aimed at solving computationally hard inverse problems in underwater acoustics is described. This project was used to study the possibilities of the sound speed profile reconstruction in a shallow-water waveguide using a dispersion-based geoacoustic inversion scheme. The computational capabilities provided by the project allowed us to investigate the accuracy of the inversion for different mesh sizes of the sound speed profile discretization grid. This problem suits well for volunteer computing because it can be easily decomposed into independent simpler subproblems.

SURFACE-GENERATED NOISE IN AN OCEAN WAVEGUIDE WITH A TRANSITION LAYER OF CONTINUOUSLY VARYING DENSITY AND SOUND SPEED

1999 ◽  
Vol 07 (04) ◽  
pp. 253-268 ◽  
Author(s):  
JIN-YUAN LIU ◽  
CHEN-FEN HUANG
Keyword(s):  
Continuous Spectrum ◽  
Sound Speed ◽  
Noise Intensity ◽  
Normal Modes ◽  
Vertical Direction ◽  
Sediment Layer ◽  
Noise Generation ◽  
Oceanic Waveguide ◽  
Noise Sources ◽  
Noise Field

This paper considers the noise field generated by surface random processes in an oceanic environment with a sediment layer possessing a continuously varying density and sound-speed profile. This model closely resembles the oceanic waveguide environment and therefore enables the simulation of surface noise generation. Many results of the noise field were generated, including the noise intensity distribution, vertical and horizontal correlations. It is demonstrated that the noise intensity may be affected by the stratification mainly through the continuous spectrum, in that the continuous spectrum is equally important as the normal modes in the present analysis. Moreover, the results for the correlations show that the noise field in the horizontal direction becomes more coherent when the noise sources are more correlated, while in the vertical direction, the results tend to reverse. The horizontal correlations of the noise field due to surface random sources with nonisotropic power spectrum, such as nonisotropic Gaussian and Pierson–Moskowitz, were generated and analyzed.

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

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.

Broadband Geoacoustic Deduction

1998 ◽  
Vol 06 (01n02) ◽  
pp. 45-59 ◽  
Author(s):  
R. M. Hamson ◽  
M. A. Ainslie
Keyword(s):  
Sound Speed ◽  
Test Cases ◽  
Data Sets ◽  
Sediment Layer ◽  
Frequency Data ◽  
Transmission Losses ◽  
Vertical Array ◽  
Starting Point ◽  
Versus Range ◽  
Speed Gradient

A two-stage approach to the geoacoustic inversion problems of selected Workshop '97 test cases is described. Initial parameters are deduced by inspection of transmission losses versus range, depth and frequency, and comparison with the calibration case. These provide a starting point for a conventional matched-field inversion applied to individual frequency data sets for a vertical array at 5-km range using the normal mode model SUPERSNAP and the standard Bartlett processor. Grid searches are carried out over pairs of parameters using: 500-Hz data to establish the sediment density and top sediment sound speed, 100-Hz data to estimate the sound speed gradient in the sediment layer and 25-Hz data for the remaining parameters. Results and error bounds are presented for two realizations of the SD workshop case. Partial results are presented for the SO case. Issues regarding SUPERSNAP/SAFARI mismatches are also discussed.

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