Verification of airgun sound field models for environmental impact assessment

Ainslie, Michael A.; Halvorsen, Michele B.; Dekeling, R.P.A.; Laws, Robert; Duncan, Alec J.; Frankel, Adam S.; Heaney, Kevin D.; Küsel, Elizabeth T.; MacGillivray, Alexander O.; Prior, Mark K.; Sertlek, Hüseyin Özkan; Zeddies, David G.

doi:10.1121/2.0000339

Cited by 15 publications

(9 citation statements)

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“…Differences between AASM and Agora-2 are likely unrelated to AASM's use of the high-frequency module because the two models diverge well below the 700-900-Hz transition band. Two other source models presented at the 2016 IAMW workshop also predicted greater overall high-frequency acoustical output than Agora-2 (see [2] for additional comparisons).…”

Section: Workhop Problem Resultsmentioning

confidence: 85%

“…Some form of artificial damping must be introduced in (1) to account for energy lost to turbulence in the isotropic bubble model, since radiative energy loss alone does not account for the observed decay of the airgun bubble oscillations. The thermodynamic properties of the bubble are encapsulated in the enthalpy term, H. Though (1) was derived for compressible water, satisfactory results are obtained by calculating the enthalpy assuming the water density is independent of pressure H = (P eff − P a ) /ρ w (2) where P a is the pressure at the bubble wall, ρ w is the water density, and P eff is the effective hydrostatic pressure at the bubble. Following Giles and Johnston [12], the effective hydrostatic pressure at each bubble is the sum of the hydrostatic pressure at depth plus the time-varying pressure fields of adjacent guns in the array.…”

Section: Aasm Low-frequency Modulementioning

confidence: 99%

“…Digital Object Identifier 10.1109/JOE.2018.2853199 low frequencies (<200 Hz) but a large mismatch at high frequencies (>1 kHz) [2]. While specific features of the predicted waveforms, such as the rise time, were identified as the cause of the mismatch, the underlying reasons for these differences remains unclear.…”

Section: Introductionmentioning

confidence: 99%

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An Airgun Array Source Model Accounting for High-Frequency Sound Emissions During Firing—Solutions to the IAMW Source Test Cases

MacGillivray¹

2019

IEEE J. Oceanic Eng.

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JASCO's Airgun Array Source Model (AASM) is a combined deterministic and stochastic model that separately treats the low-frequency and high-frequency components of signals produced by airgun arrays. The low-frequency module is based on solving the equations of motion for interacting spherical bubbles. The high-frequency module is based on a stochastic model of the airgun spectrum, which has been derived from a principal component regression analysis of the experimental data. This stochastic model determines the frequency spectrum of an airgun waveform during the rapid onset of a pressure that occurs when air is released from the gun chamber. AASM combines the output of these two modules to predict the source waveform of an airgun array over a wide frequency range (0-25 kHz). AASM was among the source models included in benchmark comparisons presented at the International Airgun Modeling Workshop (IAMW), held in Dublin, Ireland, in 2016. Results from the workshop showed that different source models agreed reasonably well at low frequencies (<200 Hz), but they diverged substantially at high frequencies (>1 kHz). To help better understand the reasons for a mismatch between source models, this paper presents solutions to the IAMW source test cases, calculated using AASM, as well as a detailed description of AASM's theoretical underpinnings.

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Section: Workhop Problem Resultsmentioning

confidence: 85%

Section: Aasm Low-frequency Modulementioning

confidence: 99%

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An Airgun Array Source Model Accounting for High-Frequency Sound Emissions During Firing—Solutions to the IAMW Source Test Cases

MacGillivray¹

2019

IEEE J. Oceanic Eng.

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“…Germany alone acquired 59,621 km of multichannel seismic survey lines between 1976 and 2011 (Boebel et al, 2009;Breitzke, 2014). Seismic airgun arrays emit broadband (5 Hz-20 kHz) pulses repeatedly (every 5-20 s) at levels up to 224 dB re 1 µPa 2 m 2 s (Ainslie et al, 2016;Li and Bayly, 2017).…”

Section: Underwater Antarctic Noisementioning

confidence: 99%

Managing the Effects of Noise From Ship Traffic, Seismic Surveying and Construction on Marine Mammals in Antarctica

et al. 2019

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Erbe et al. Antarctic Underwater Noise score was a refinement of noise exposure criteria. Environmental evaluations are a requirement before conducting activities in the Antarctic. Because of a lack of scientific data on impacts, requirements and noise thresholds often vary between countries that conduct these evaluations, leading to different standards across countries. Addressing the identified research needs will help to implement informed and reasonable thresholds for noise production in the Antarctic and help to protect the Antarctic environment.

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“…The total volume in an airgun array is between 49 000 cm 3 and 130 000 cm 3 (3000 in 3 and 8000 in 3 ), and the pressure is $13 800 kPa (2000 lbf/in 2 ) (Caldwell and Dragoset, 2000). Sounds recorded from conventional airguns may have high-frequency content (>1 kHz), but the characteristics of the airgun sounds that harbor porpoises are exposed to in the wild vary according to the type of airgun used, the geometry of the array, propagation effects and the distance and position of an animal relative to the airgun array (Caldwell and Dragoset, 2000;Madsen et al, 2006;Lucke et al, 2009;Landrø et al, 2011;Sertlek and Ainslie, 2015;Thompson et al, 2013;Hermannsen et al, 2015;Ainslie et al, 2016). The smaller volume and lower pressure of the airgun used in this study (see also Hermannsen et al, 2015) resulted in a higher dominant frequency ($50 Hz rather than $20 Hz) and a somewhat smaller bandwidth (40 Hz measured at À10 dB, rather than 100 Hz) than found in full arrays used for seismic surveying (Caldwell and Dragoset, 2000).…”

Section: A Evaluationmentioning

confidence: 99%

Temporary hearing threshold shift in a harbor porpoise (Phocoena phocoena) after exposure to multiple airgun sounds

Kastelein¹,

Helder-Hoek²,

Voorde³

et al. 2017

The Journal of the Acoustical Society of America

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In seismic surveys, reflected sounds from airguns are used under water to detect gas and oil below the sea floor. The airguns produce broadband high-amplitude impulsive sounds, which may cause temporary or permanent threshold shifts (TTS or PTS) in cetaceans. The magnitude of the threshold shifts and the hearing frequencies at which they occur depend on factors such as the received cumulative sound exposure level (SELcum), the number of exposures, and the frequency content of the sounds. To quantify TTS caused by airgun exposure and the subsequent hearing recovery, the hearing of a harbor porpoise was tested by means of a psychophysical technique. TTS was observed after exposure to 10 and 20 consecutive shots fired from two airguns simultaneously (SELcum: 188 and 191 dB re 1 μPas) with mean shot intervals of around 17 s. Although most of the airgun sounds' energy was below 1 kHz, statistically significant initial TTS (1-4 min after sound exposure stopped) of ∼4.4 dB occurred only at the hearing frequency 4 kHz, and not at lower hearing frequencies tested (0.5, 1, and 2 kHz). Recovery occurred within 12 min post-exposure. The study indicates that frequency-weighted SELcum is a good predictor for the low levels of TTS observed.

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Verification of airgun sound field models for environmental impact assessment

Cited by 15 publications

References 0 publications

An Airgun Array Source Model Accounting for High-Frequency Sound Emissions During Firing—Solutions to the IAMW Source Test Cases

An Airgun Array Source Model Accounting for High-Frequency Sound Emissions During Firing—Solutions to the IAMW Source Test Cases

Managing the Effects of Noise From Ship Traffic, Seismic Surveying and Construction on Marine Mammals in Antarctica

Temporary hearing threshold shift in a harbor porpoise (Phocoena phocoena) after exposure to multiple airgun sounds

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