Statistics of Sound Propagation in the Ocean

Dyer, Ira

doi:10.1121/1.1912133

Cited by 96 publications

(62 citation statements)

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“…For example, at 1228 Hz the standard deviation when the source is on is on the order of 1 dB. When the source is off the standard deviation is on the order of 5 dB, in agreement with the 5.6 dB standard deviation of noise caused by distance sources predicted by Dyer [118]. Further, the peaks in the standard deviation seen for 220.5, 415, and 635 Hz correspond to the destructive interference nulls in the received signal levels where the received signal is noise dominated.…”

Section: Error Analysissupporting

confidence: 71%

“…2 )exp(y − exp(y)/2σ 2 ), the log density [118]. However, about the most probable point, the log density can be approximated by a gaussian density, which simplifies the analysis.…”

Section: Error Analysismentioning

confidence: 99%

“…Further, the peaks in the standard deviation seen for 220.5, 415, and 635 Hz correspond to the destructive interference nulls in the received signal levels where the received signal is noise dominated. In this case, one can consider the noise to be the contribution of the other tones, as well as distant noise, which would give an expected standard deviation between 2.3 dB and 5.6 dB [118]. Therefore, in determining the error caused by the variation in the received signal level, one must exclude the artificially large standard deviations caused by interference effects.…”

Section: Error Analysismentioning

confidence: 99%

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Investigation of ocean acoustics using autonomous instrumentation to quantify the water-sediment boundary properties

Carey

Holmes

2006

The Journal of the Acoustical Society of America

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Several noise criteria methods commonly used in architectural acoustics have been quantitatively related to noise perception and task performance under a variety of ventilation systems-induced background noise conditions. Noise criteria, balanced noise criteria, room criteria, room criteria mark II, and A-weighted equivalent sound pressure level were examined. The first phase of the project included noise conditions controlled to be non-time-varying and nontonal, with neutral, rumbly, roaring, or hissy characteristics. An intermediate study examined exposure time length and types of performance tasks used. The final phase included noise conditions containing various levels of discrete tones from 120 to 595 Hz. Under each noise, subjects completed performance tasks and perception questionnaires. Results indicate task performance was significantly affected by perception of noise, but this relationship was not fully demonstrated by the criteria systems analyzed. The five criteria were generally well suited in describing subjective loudness perception, but some discrepancies in criteria spectral quality ratings and subjective perception existed. Finally, perception of annoyance changed based on the frequency and prominence of tones in noise, but these changes were not reflected in the criteria level or spectral quality ratings. Modifications to the existing criteria are recommended.

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Section: Error Analysissupporting

confidence: 71%

“…2 )exp(y − exp(y)/2σ 2 ), the log density [118]. However, about the most probable point, the log density can be approximated by a gaussian density, which simplifies the analysis.…”

Section: Error Analysismentioning

confidence: 99%

Section: Error Analysismentioning

confidence: 99%

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Investigation of ocean acoustics using autonomous instrumentation to quantify the water-sediment boundary properties

Carey

Holmes

2006

The Journal of the Acoustical Society of America

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“…The resultant modal amplitudes for mode one incident are shown in [7] showed that for a fixed source and receiver in the SWARM95 experiment, situated across the mean direction of the internal wave crests, the root mean square of the log-intensity over a several hour time window was near 5.6 dB, the statistical value expected for fully saturated ocean waveguides [58,59]. …”

Section: A Multiple Wavesmentioning

confidence: 99%

Three-dimensional acoustic propagation through shallow water internal, surface gravity and bottom sediment waves

Shmelev¹

2011

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This thesis describes the physics of fully three-dimensional low frequency acoustic interaction with internal waves, bottom sediment waves and surface swell waves that are often observed in shallow waters and on continental slopes. A simple idealized model of the ocean waveguide is used to analytically study the properties of acoustic normal modes and their perturbations due to waves of each type. The combined approach of a semi-quantitative study based on the geometrical acoustics approximation and on fully three-dimensional coupled mode numerical modeling is used to examine the azimuthal dependence of sound wave horizontal reflection from, transmission through and ducting between straight parallel waves of each type. The impact of the natural crossings of nonlinear internal waves on horizontally ducted sound energy is studied theoretically and modeled numerically using a three-dimensional parabolic equation acoustic propagation code. A realistic sea surface elevation is synthesized from the directional spectrum of long swells and used for three-dimensional numerical modeling of acoustic propagation. As a result, considerable normal mode amplitude scintillations were observed and shown to be strongly dependent on horizontal azimuth, range and mode number. Full field numerical modeling of low frequency sound propagation through large sand waves located on a sloped bottom was performed using the high resolution bathymetry of the mouth of San Francisco Bay. Very strong acoustic ducting is shown to steer acoustic energy beams along the sand wave's curved crests.

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“…He showed that for a fixed source and receiver situated across the mean direction of the internal wave crests, the root mean square of the log-intensity over a several hour time window was near 5.6 dB, the statistical value expected for fully saturated ocean waveguides. 37 …”

Section: B Multiple Wavesmentioning

confidence: 99%

Three-dimensional coupled mode analysis of internal-wave acoustic ducts

Shmelev

Lynch

Lin

et al. 2014

The Journal of the Acoustical Society of America

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A fully three-dimensional coupled mode approach is used in this paper to describe the physics of low frequency acoustic signals propagating through a train of internal waves at an arbitrary azimuth. A three layer model of the shallow water waveguide is employed for studying the properties of normal modes and their coupled interaction due to the presence of nonlinear internal waves. Using a robust wave number integration technique for Fourier transform computation and a direct global matrix approach, an accurate three-dimensional coupled mode full field solution is obtained for the tonal signal propagation through straight and parallel internal waves. This approach provides accurate results for arbitrary azimuth and includes the effects of backscattering. This enables one to provide an azimuthal analysis of acoustic propagation and separate the effects of mode coupled transparent resonance, horizontal reflection and refraction, the horizontal Lloyd's mirror, horizontal ducting and anti-ducting, and horizontal tunneling and secondary ducting.

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Statistics of Sound Propagation in the Ocean

Cited by 96 publications

References 0 publications

Investigation of ocean acoustics using autonomous instrumentation to quantify the water-sediment boundary properties

Investigation of ocean acoustics using autonomous instrumentation to quantify the water-sediment boundary properties

Three-dimensional acoustic propagation through shallow water internal, surface gravity and bottom sediment waves

Three-dimensional coupled mode analysis of internal-wave acoustic ducts

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