Intensity-range relations in oceanographic acoustics

Weston, D. E.

doi:10.1016/0022-460x(71)90350-6

Cited by 96 publications

(53 citation statements)

References 20 publications

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“…The loss mechanisms in the deep water environment can be expressed as energy flux (Weston, 1971), in terms describing spherical and cylindrical spreading, surface scattering and absorption: TL = 20 log r T + 10 log͑r/r T ͒ + 10 log µ + 10 −3 ␣r ͑dB͒, ͑5͒…”

Section: Deep Water Environmentmentioning

confidence: 99%

Ocean acidification and its impact on ocean noise: Phenomenology and analysis

Reeder

Chiu

2010

The Journal of the Acoustical Society of America

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Ocean acidification has been observed since the beginning of the industrial era and is expected to further reduce ocean pH in the future. A significant increase in ocean noise has been suggested based upon the percentage change in acoustic absorption coefficient at low frequencies. Presented here is an analysis using transmission loss models of all relevant loss mechanisms for three environments experiencing a significant near-surface pH reduction of 8.1–7.4. Results show no observable change in the shallow water and surface duct environments, and a statistically insignificant change of less than 0.5 dB for all frequencies in the deep water environment.

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Section: Deep Water Environmentmentioning

confidence: 99%

Ocean acidification and its impact on ocean noise: Phenomenology and analysis

Reeder

Chiu

2010

The Journal of the Acoustical Society of America

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“…4 discrete components are noticeable which are the effect of activity of main engines, shaft lines and propeller, and also an electric generating set. Each particular component was distinguished by a successive number, namely one group of numbers (2, 4, 6, 8, 10, 12, 14, 17, 19, 21) indicate components coming from propeller and shaft lines, and other group of numbers (1,3,5,7,9,11,13,15,16,17,18,20,22,23,24,25) show components coming from working main engines. The identification results obtained by using the method in question have been confirmed in the following papers [4][5][6][7].…”

Section: Results Of In Situ Investigationmentioning

confidence: 99%

“…In order to explain this phenomenon, simulation of a description of these rays was carried out [4]. In the simulation theoretical model of Weston [3] was used describing the propagation of waves in the sea. For simplicity, the model assumed a depth measurement h = 20 m, speed of sound in water, c = 1450 m/s, and also assumed that the medium is lossless.…”

Section: Characteristic Forms Of Ship Noise Spectrograms Connected Tomentioning

confidence: 99%

“…7. Just as the ship was directly above the sensor, a wavelength of standing wave was 40 m. The length of this wave sets the creation of the fundamental mode, which is associated with the depth [3,6].…”

Section: Characteristic Forms Of Ship Noise Spectrograms Connected Tomentioning

confidence: 99%

“…For decades the high interest in acoustic noise produced by ships, has caused that it was subject of intense investigation, both theoretical and experimental [1][2][3]. The primary practical aspect of this investigation is military usage of noise produced by ships in reference to their detection and localization.…”

Section: Introductionmentioning

confidence: 99%

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Shipping Low Frequency Noise and Its Propagation in Shallow Water

Kozaczka

Grelowska

2011

Acta Phys. Pol. A

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One of the most significant factor influencing acoustical climate of the sea is underwater noise generated by moving ships. If the considered sea area has features of the shallow water, namely the wave frequency fulfils relation f < 10c h , where c denotes phase speed of sound, and h is depths of the sea, then in certain distance from the wave source specific image of sound pressure distribution in the mean of wave modes appears. The modes constitute wave packet propagating with group speed in the direction parallel to the sea surface. The paper presents results of the experimental investigation concerning the distribution of the sound field created by moving ship in the shallow water, in a small distance from the ship. The main acoustical characteristics, describing features of the field are spectrograms in pseudo-3D system: distance and frequency in geometrical form, and sound intensity in the optical one (color). Results presented in such a way pointed individual features of the sound source known often as acoustical signature of the source (ship).

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Exposure of individual harbour seals (Phoca vitulina) and waters surrounding protected habitats to acoustic deterrent noise from aquaculture

Findlay

Hastie

Farcas

et al. 2022

Aquatic Conservation

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1. Pinniped depredation at aquaculture sites is a globally recognized problem. To mitigate depredation, the aquaculture sector uses acoustic deterrent devices (ADDs) as a non-lethal alternative to shooting pinnipeds interacting with caged finfish. However, it is unclear whether sound emissions from ADDs have the potential to also impact non-target pinnipeds at spatial scales relevant to populations.2. Global Positioning System (GPS) tracking data from seven harbour seals tagged in a non-aquaculture context, on the west coast of Scotland, in 2017 were combined with modelled maps of ADD noise to quantify sound exposure and estimate the potential for auditory impairment. The acoustic model applied an energy flux approach across the main frequency range of ADDs (2-40 kHz).Predictions of temporary and permanent auditory threshold shifts were made using seal location data and published noise exposure criteria. The acoustic exposure of waters (10-km buffers) surrounding protected habitats (i.e. designated haul outs and Special Areas of Conservation (SACs)) on the west coast of Scotland was also assessed.3. All tagged seals and waters surrounding 51 of 56 protected sites were predicted to be exposed to ADD noise exceeding median ambient sound levels. Temporary auditory impairment was predicted to occur in one of the seven tagged harbour seals and across 1.7% of waters surrounding protected habitats over a 24-hour period, when assuming a 100% ADD duty cycle.4. Although the predicted risk of auditory impairment appears to be relatively low, these findings suggest that harbour seals inhabiting inshore waters off western Scotland are routinely exposed to ADD noise that exceeds median ambient sound levels. This chronic exposure risks negative consequences for individual harbour seals among the wider population in this region. The use of ADDs to mitigate pinniped depredation should be carefully considered to reduce unintended habitat-wide impacts on non-target species, including pinnipeds that are not specifically interacting with aquaculture.

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Intensity-range relations in oceanographic acoustics

Cited by 96 publications

References 20 publications

Ocean acidification and its impact on ocean noise: Phenomenology and analysis

Ocean acidification and its impact on ocean noise: Phenomenology and analysis

Shipping Low Frequency Noise and Its Propagation in Shallow Water

Exposure of individual harbour seals (Phoca vitulina) and waters surrounding protected habitats to acoustic deterrent noise from aquaculture

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