Prediction of underwater sound levels from rain and wind

Ma, Barry; Nystuen, Jeffrey A.; Lien, Ren‐Chieh

doi:10.1121/1.1910283

Cited by 100 publications

(60 citation statements)

References 16 publications

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“…The primary mechanisms of ocean-surface agitation are wind-generated breaking waves and the impact of raindrops (Franz 1959, Ma et al 2005. Surface impacts have 2 distinct noise generation mechanisms, both of which radiate preferentially downward, with cosine directionality.…”

Section: Noise Due To Surface Motionmentioning

confidence: 99%

Anthropogenic and natural sources of ambient noise in the ocean

Hildebrand¹

2009

Mar. Ecol. Prog. Ser.

877

576

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Ocean ambient noise results from both anthropogenic and natural sources. Different noise sources are dominant in each of 3 frequency bands: low (10 to 500 Hz), medium (500 Hz to 25 kHz) and high (> 25 kHz). The low-frequency band is dominated by anthropogenic sources: primarily, commercial shipping and, secondarily, seismic exploration. Shipping and seismic sources contribute to ambient noise across ocean basins, since low-frequency sound experiences little attenuation, allowing for long-range propagation. Over the past few decades the shipping contribution to ambient noise has increased by as much as 12 dB, coincident with a significant increase in the number and size of vessels comprising the world's commercial shipping fleet. During this time, oil exploration and construction activities along continental margins have moved into deeper water, and the long-range propagation of seismic signals has increased. Medium frequency sound cannot propagate over long ranges, owing to greater attenuation, and only local or regional (10s of km distant) sound sources contribute to the ambient noise field. Ambient noise in the mid-frequency band is primarily due to sea-surface agitation: breaking waves, spray, bubble formation and collapse, and rainfall. Various sonars (e.g. military and mapping), as well as small vessels, contribute anthropogenic noise at mid-frequencies. At high frequencies, acoustic attenuation becomes extreme so that all noise sources are confined to an area close to the receiver. Thermal noise, the result of Brownian motion of water molecules near the hydrophone, is the dominant noise source above about 60 kHz.

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Section: Noise Due To Surface Motionmentioning

confidence: 99%

Anthropogenic and natural sources of ambient noise in the ocean

Hildebrand¹

2009

Mar. Ecol. Prog. Ser.

877

576

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“…The steep slope, and decrease in PSD compared to the previous day, indicates attenuation of SGN at high frequencies. We suggest that this attenuation could be due to the characteristic subsurface bubble layer associated with heavy rainfall (Ma et al, 2005).…”

Section: Figmentioning

confidence: 99%

“…Following an acoustically active period, quiescent entrained bubbles can act as scatterers; this is generally more relevant in the breaking-wave case, where wave-induced turbulence entrains bubbles and thus extends bubble-scatterer lifetime in the water column (Deane et al, 2013). However, in heavy rainfall, subsurface bubble layer effects have been found to result in decreased sound levels at high frequencies through reduced sound speed and increased attenuation (Ma et al, 2005).…”

Section: F Rainfall Noisementioning

confidence: 99%

“…This indicates the resonance effect of a given bubble size range created by small raindrops ("type II" bubbles after Ma et al, 2005), which introduce sound at 13-25 kHz, as well as the less significant impact noise generated over a wide frequency band. The previous-day spectra were recorded during flows of ∼ 1 m/s (depth-averaged), indicating that SGN intensity would be below its peak value.…”

Section: Figmentioning

confidence: 99%

“…The initial impact sound, by contrast, is generated with every drop, with an intensity that increases with velocity and drop size. The combination of factors contributing to a rain noise signature was investigated by Ma et al (2005), who characterized acoustic observations and mechanisms based on rainfall parameters. It was also noted that tiny raindrops (<0.8 mm) do not have an observable acoustic signature.…”

Section: F Rainfall Noisementioning

confidence: 99%

See 2 more Smart Citations

Soundscape characterization in a dynamic acoustic environment: Grand Passage, Nova Scotia, a planned in-stream tidal energy site

Lombardi¹,

Hay²,

Barclay³

2016

Proceedings of Meetings on Acoustics

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The marine environment in the Bay of Fundy hosts a dynamic and diverse soundscape that is a fundamental component of the local ecosystem. The emergence of new human marine activities and infrastructure, such as tidal turbine installations, introduces new sound sources that change or disrupt the existing acoustic environment, but the full extent of these changes is not well understood and is not predictable. To better evaluate the effects of future tidal energy development on the local soundscape in Grand Passage, Nova Scotia, a thorough understanding of the pre-development characteristics must be established. The present research seeks to identify existing anthropophony, biophony, and geophony, and to evaluate the underlying mechanisms contributing to geophonic variability. Passive acoustic measurements have been conducted using long-term moored omnidirectional hydrophones, a moored 5-channel array, and drifting hydrophone arrays, enabling identification of dominant signals and source direction, estimation of pseudonoise masking effects due to turbulent flow, and analysis of diurnal, daily, seasonal, and annual variability as well as spatial variability within the study area. This paper provides an overview of the dominant sound sources and discusses the effects of environmental forcing on soundscape characteristics.

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Sediment‐generated noise and bed stress in a tidal channel

2013

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[1] Tidally driven currents and bed stresses can result in noise generated by moving sediments. At a site in Admiralty Inlet, Puget Sound, Washington State (USA), peak bed stresses exceed 20 Pa. Significant increases in noise levels are attributed to mobilized sediments at frequencies from 4-30 kHz with more modest increases noted from 1-4 kHz. Sediment-generated noise during strong currents masks background noise from other sources, including vessel traffic. Inversions of the acoustic spectra for equivalent grain sizes are consistent with qualitative data of the seabed composition. Bed stress calculations using log layer, Reynolds stress, and inertial dissipation techniques generally agree well and are used to estimate the shear stresses at which noise levels increase for different grain sizes. Regressions of the acoustic intensity versus near-bed hydrodynamic power demonstrate that noise levels are highly predictable above a critical threshold despite the scatter introduced by the localized nature of mobilization events.

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Prediction of underwater sound levels from rain and wind

Cited by 100 publications

References 16 publications

Anthropogenic and natural sources of ambient noise in the ocean

Anthropogenic and natural sources of ambient noise in the ocean

Soundscape characterization in a dynamic acoustic environment: Grand Passage, Nova Scotia, a planned in-stream tidal energy site

Sediment‐generated noise and bed stress in a tidal channel

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