Searched for: +
(1 - 20 of 21)

Pages

document
Lippert, T. (author), Ainslie, M.A. (author), von Estorff, O. (author)
Sound produced by marine pile driving activities poses a possible risk to marine life. The assessment and mitigation of this risk requires a precise prediction of the expected levels. An analytical approach to estimate the radiated sound exposure levels is presented, based on the axial symmetry of the problem, resulting in damped cylindrical...
article 2018
document
von Benda-Beckmann, A.M. (author), Thomas, L. (author), Tyack, P.L. (author), Ainslie, M.A. (author)
Passive acoustic monitoring with widely-dispersed hydrophones has been suggested as a cost-effective method to monitor population densities of echolocating marine mammals. This requires an estimate of the area around each receiver over which vocalizations are detected - the "effective detection area" (EDA). In the absence of auxiliary...
article 2018
document
Kastelein, R.A. (author), Helder-Hoek, L. (author), van de Voorde, S. (author), von Von Benda-Beckmann, A.M. (author), Lam, F.P.A. (author), Jansen, E. (author), de Jong, C.A.F. (author), Ainslie, M.A. (author)
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...
article 2017
document
Ainslie, M.A. (author), Leighton, T.G. (author)
The set of formulations commonly known as “the sonar equations” have for many decades been used to quantify the performance of sonar systems in terms of their ability to detect and ocalize objects submerged in seawater. The efficacy of the sonar equations, with individualterms evaluated in decibels, is well established in Earth’s oceans. The...
article 2016
document
Sertlek, H.Ö. (author), Binnerts, B. (author), Ainslie, M.A. (author)
Sound mapping over large areas can be computationally expensive because of the large number of sources and large source-receiver separations involved. In order to facilitate computation, a simplifying assumption sometimes made is to neglect the sound speed gradient in shallow water. The accuracy of this assumption is investigated for ship...
article 2016
document
Wensveen, P.J. (author), von Benda-Beckmann, A.M. (author), Ainslie, M.A. (author), Lam, F.P.A. (author), Kvadsheim, P.H. (author), Tyack, P.L. (author), Miller, P.J.O. (author)
The behaviour of a marine mammal near a noise source can modulate the sound exposure it receives.We demonstrate that two long-finned pilot whales both surfaced in synchrony with consecutive arrivals of multiple sonar pulses. We then assess the effect of surfacing and other behavioural response strategies on the received cumulative sound exposure...
article 2015
document
Sivle, L.D. (author), Kvadsheim, P.H. (author), Ainslie, M.A. (author)
For conservation purposes, it is important to evaluate potential population consequences of noise disturbance. Based on maximum reported sound levels of no response to sonar, a mathematical model is used to predict the potential risk to the population of herring (Clupea harengus) when these levels are exceeded. Results show that risk varies with...
article 2015
document
von Benda-Beckmann, A.M. (author), Aarts, G. (author), Sertlek, H.O. (author), Lucke, K. (author), Verboom, W.C. (author), Kastelein, R.A. (author), Ketten, D.R. (author), van Bemmelen, R. (author), Lam, F.P.A. (author), Kirkwood, R. (author), Ainslie, M.A. (author)
(UXO) are still present in the North Sea. UXO are frequently accidentally encountered by fishermen and dredging vessels. Out of concern for human safety and to avoid damage to equipment and infrastructure from uncontrolled explosions, most reported UXO found in the Dutch Continental Shelf (DCS) are detonated in a controlled way. These underwater...
article 2015
document
van der Schaar, M. (author), Ainslie, M.A. (author), Robinson, S.P. (author), Prior, M.K. (author), André, M. (author)
The growing scientific and societal concerns about the effects of underwater sound on marine ecosystems have been recently recognised through the introduction of several international initiatives, like the International Quiet Ocean Experiment, aimed at measuring the environmental impact of ocean noise on large spatial and temporal scales. From a...
article 2014
document
Sertlek, H.O. (author), Ainslie, M.A. (author)
In shallow water propagation, the sound field depends on the proximity of the receiver to the sea surface, the seabed, the source depth, and the complementary source depth. While normal mode theory can predict this depth dependence, it can be computationally intensive. In this work, an analytical solution is derived in terms of the Faddeeva...
article 2014
document
van Vossen, R. (author), Eidem, E.J. (author), Ivansson, S. (author), Chalindar, B. (author), Dybedal, J. (author), Colin, M.E.G.D. (author), Benders, F.P.A. (author), Andersson, B.L. (author), Juhel, B. (author), Cristol, X. (author), Olsen, G.K. (author), Pihl, J.N.B. (author), Tveit, E. (author), Jespers, S. (author), Ainslie, M.A. (author)
Accurate environmental information is required for obtaining confident sonar performance predictions. This environmental information is, however, often unreliable or unavailable. To support antisubmarine warfare (ASW) operations, a through-the-sensor approach has been developed in which relevant acoustic seabed properties are derived from...
article 2014
document
Miller, P.J.O. (author), Antunes, R.N. (author), Wensveen, P.J. (author), Samarra, F.I.P. (author), Alves, A.C. (author), Tyack, P.L. (author), Kvadsheim, P.H. (author), Kleivane, L. (author), Lam, F.P.A. (author), Ainslie, M.A. (author), Thomas, L. (author)
Eight experimentally controlled exposures to 1−2 kHz or 6−7 kHz sonar signals were conducted with four killer whale groups. The source level and proximity of the source were increased during each exposure in order to reveal response thresholds. Detailed inspection of movements during each exposure session revealed sustained changes in speed and...
article 2014
document
von Benda-Beckmann, A.M. (author), Wensveen, P.J. (author), Kvadsheim, P.H. (author), Lam, F.P.A. (author), Miller, P.J.O. (author), Tyack, P.L. (author), Ainslie, M.A. (author)
Ramp-up or soft-start procedures (i.e., gradual increase in the source level) are used to mitigate the effect of sonar sound on marine mammals, although no one to date has tested whether ramp-up procedures are effective at reducing the effect of sound on marine mammals. We investigated the effectiveness of ramp-up procedures in reducing the area...
article 2013
document
Ainslie, M.A. (author)
The detection performance of an active sonar depends on the intensity of the signal (target echo) relative to that of a background of reverberation plus noise. The echo is calculated for a standard test problem by convolving the time-domain impulse response at the target position with itself. The same approach is applied to a closely related...
article 2013
document
Ainslie, M.A. (author)
Passive acoustic monitoring with a single hydrophone has been suggested as a cost-effective method to monitor population density of echolocating marine mammals, by estimating the distance at which the hydrophone is able to intercept the echolocation clicks and distinguish these from the background. To avoid a bias in the estimated population...
article 2013
document
Dol, H.S. (author), Colin, M.E.G.D. (author), Ainslie, M.A. (author), van Walree, P.A. (author), Janmaat, J. (author)
Abstract—Sea-surface scattering by wind-generated waves and bubbles is regarded to be the main nonplatform related cause of the time variability of shallow acoustic communication channels. Simulations for predicting the quality of acoustic communication links in such channels thus require adequate modeling of these dynamic sea-surface effects....
article 2013
document
Zampolli, M. (author), Nijhof, M.J.J. (author), de Jong, C.A.F. (author), Ainslie, M.A. (author), Jansen, E.H.W. (author), Quesson, B.A.J. (author)
The acoustic radiation from a pile being driven into the sediment by a sequence of hammer strikes is studied with a linear, axisymmetric, structural acoustic frequency domain finite element model. Each hammer strike results in an impulsive sound that is emitted from the pile and then propagated in the shallow water waveguide. Measurements from...
article 2013
document
Heinis, F. (author), de Jong, C.A.F. (author), Ainslie, M.A. (author), Borst, W. (author), Vellinga, T. (author)
The Port of Rotterdam is expanding to meet the growing demand to accommodate large cargo vessels. The construction of Maasvlakte 2 (MV2) started in September 2008. One of the licensing conditions is the monitoring of the underwater sound produced during its construction, with an emphasis on the establishment of acoustic source levels of the...
article 2013
document
Sivle, L.D. (author), Kvadsheim, P.H. (author), Ainslie, M.A. (author), Solow, A. (author), Handegard, N.O. (author), Miller, P.J.O. (author), Nordlund, N. (author), Lam, F.P.A. (author)
Naval anti-submarine sonars produce intense sounds within the hearing range of Atlantic herring (Clupea harengus). In this study, schools of Atlantic herring were exposed to sonar signals of 1–2 kHz (low-frequency active sonar, LFAS) and 6–7 kHz (mid-frequency active sonar, MFAS) and playbacks of killer whale feeding sounds during their summer...
article 2012
document
van Vossen, R. (author), Ainslie, M.A. (author)
Reliable predictions of sea-surface backscattering strength are required for sonar performance modeling. These are, however, difficult to obtain as measurements of sea-surface backscattering are not available at small grazing angles relevant to low-frequency active sonar (1-3 kHz). Accurate theoretical predictions of scattering strength require...
article 2011
Searched for: +
(1 - 20 of 21)

Pages