Michael Ainslie

Michael Ainslie
JASCO Research Ltd | JASCO

About

195
Publications
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2,231
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Publications

Publications (195)
Article
The habitat of the endangered southern resident killer whale (SRKW) overlaps major international shipping lanes near the Port of Vancouver, British Columbia. Shipping is a dominant source of underwater noise, which can hinder SRKW key life functions. To reduce environmental pressure on the SRKWs, Vancouver Fraser Port Authority offers incentives fo...
Article
Full-text available
Applications of underwater acoustics include sonar, communication, geophysical imaging, acoustical oceanography, and bioacoustics. Specialists typically work with little interdisciplinary interaction, and the terminology they employ has evolved separately in each discipline, to the point that transdisciplinary misunderstandings are common. Furtherm...
Article
The acoustical output of marine-seismic airguns is determined from recordings of the sound pressure made on hydrophones suspended below a floating barge from which the airguns are also deployed. The signals from multiple types of airguns are considered and each type is operated over a range of deployment depths and chamber pressures. The acoustical...
Technical Report
Full-text available
Best Practice Guide for Underwater Particle Motion Measurement for Biological Applications
Article
No PDF available ABSTRACT The Atlantic deep-water Ecosystem Observation Network project (https://adeon.unh.edu/) deployed seven autonomous long-term observatory landers in waters between 250 and 900 m deep along the east coast of the United States for three years (November 2017–November 2020). The objectives of the project included quantifying the...
Technical Report
Full-text available
This report is the result of Phase 2 of a two-phase project for the standardization of measurement, processing and reporting procedures for offshore oil and gas exploration and production-related sound sources. This project was carried out for the Sound and Marine Life Joint Industry Programme of the International Association of Oil & Gas Producers...
Article
The soundscape of the Northeast Pacific Ocean is studied with emphasis on frequencies in the range 63–125 Hz. A 34-year (1964–1998) increase and seasonal fluctuations (1994–2006) are investigated. This is achieved by developing a simple relationship between the total radiated power of all ocean sound sources and the spatially averaged mean-square s...
Article
Modern active sonar systems can (almost) continuously transmit and receive sound, which can lead to more masking of important sounds for marine mammals than conventional pulsed sonar systems transmitting at a much lower duty cycle. This study investigated the potential of 1-2 kHz active sonar to mask echolocation-based foraging of sperm whales by m...
Article
Geophysical exploration of the seabed is typically done through seismic surveys, using airgun arrays that produce intense, low-frequency-sound pulses¹ that can be heard over hundreds of square kilometers, 24/7.²,³ Little is known about the effects of these sounds on free-ranging fish behavior.4, 5, 6 Effects reported range from subtle individual ch...
Article
Regulations for underwater anthropogenic noise are typically formulated in terms of peak sound pressure, root-mean-square sound pressure, and (weighted or unweighted) sound exposure. Sound effect studies on humans and other terrestrial mammals suggest that in addition to these metrics, the impulsiveness of sound (often quantified by its kurtosis β)...
Article
Environmental risk assessment for impact pile driving requires characterization of the radiated sound field. Damped cylindrical spreading (DCS) describes propagation of the acoustic Mach cone generated by striking a pile and predicts sound exposure level ( L E) versus range. For known water depth and sediment properties, DCS permits extrapolation f...
Conference Paper
Understanding the influence of changes in shipping intensity on the temporal and spatial distribution of underwater sound is needed for marine spatial planning. We introduce a practical approach for the estimation of underwater shipping sound for both past and future. Shipping sound has been identified as one of the largest contributors to the Dutc...
Article
No PDF available ABSTRACT Pile driving for the installation of wind farms has become a recent topic of interest as we seek to learn how to protect the marine environment while energy efficient offshore turbines are installed. For environmental compliance, propagation models for spreading from a point source are sometimes used to evaluate impact vol...
Conference Paper
Full-text available
Abstract: To support North Sea countries to comply with EU legislation, a framework for a fully operational joint monitoring programme for ambient noise in the North Sea is developed in the Interreg Joint Monitoring Programme for Ambient Noise North Sea (JOMOPANS). A key task in the project is to develop and demonstrate verified and validated model...
Article
The papers in this special issue had its origins in the International Airgun Modeling Workshop (the Workshop), which took place in Dublin, Ireland, on July 16, 2016. The purpose of the Workshop was to address the demand for increasingly precise assessment of the environmental impacts of seismic surveys. However, an increase in precision requires ac...
Article
The papers in this special issue focuses on the verification and validation of models for predicting the sound field radiated by air guns and air gun arrays. This issue aims to address the demand for increasingly precise assessments of environmental impacts, requiring accurate characterization of the air gun array sound field, including the interfa...
Article
Computer models can be used to predict the sound field near an airgun or airgun array. The accuracy of such predictions can be assessed either by a process of verification (comparison with alternative theoretical solution to the same computational problem) or by validation (comparison with measurement). A set of verification test problems is descri...
Article
Full-text available
Offshore activities elevate ambient sound levels at sea, which may affect marine fauna. We reviewed the literature about impact of airgun acoustic exposure on fish in terms of damage, disturbance and detection and explored the nature of impact assessment at population level. We provided a conceptual framework for how to address this interdisciplina...
Article
To understand the consequences of underwater noise exposure for cetaceans, there is a need for assessments of behavioural responses over increased spatial and temporal scales. Bottom-moored acoustic recorders and satellite tags provide such long-term and large spatial coverage of behaviour compared to short-duration acoustic-recording tags. However...
Data
A movie of weekly averaged sound maps is provided as a supplementary information. (https://www.sciencedirect.com/science/article/pii/S0269749118344932#mmc1)
Article
Effective measures for protecting and preserving the marine environment require an understanding of the potential impact of anthropogenic sound on marine life. A crucial component is a proper assessment of the anthropogenic soundscape: which sounds are present where, when and how strong? We provide an extensive case study modelling the spatial, tem...
Article
Comparisons are made of sound pressure and particle acceleration predicted by two methods in the vicinity of two arrays of marine-seismic airguns. Data describing the array properties and the environmental conditions are taken from test cases designed to facilitate intermodel comparison. The two propagation approaches, one based on method of images...
Article
An analytical formulation for the calculation of the range and depth-dependence of propagation loss in isospeed water is introduced. The range-dependent bathymetry is handled with Weston's ray invariant approach, requiring a gradually varying water depth. The depth dependence of propagation loss is formulated using a transformation from an incohere...
Article
To protect marine life, piling activities at sea are subject to regulations on sound emission. Different regulatory authorities base different action criteria based on different statistics of the emitted sound pressure. Modelling efforts to predict these metrics have achieved mixed success. While the sound exposure level (SEL) can be predicted rela...
Article
Fish rely on their auditory system for survival to detect and interpret sounds in their surroundings, especially those originating from predators, prey, and conspecifics. The sensitivity of fish hearing can be impaired, for example, by masking or temporary threshold shifts. To understand and quantify the impact of noise in the oceans, we need a qua...
Article
Full-text available
Naval sonar signals may affect the behavior of harbor porpoises (Phocoena phocoena). The 53C sonar system produces 1,600 ms sonar signals in the 3.5 to 4.1 kHz band, each consisting of a sweep immediately followed by two tones which are separated by a 100 ms silence. Effects of sound pressure level (SPL) and duty cycle on the behavioral responses o...
Preprint
Full-text available
Computer models can be used to predict the sound field in the vicinity of an airgun or airgun array. The accuracy of such predictions can be assessed either by a process of verification (comparison with alternative theoretical solution to the same computational problem) or by validation (comparison with measurement). A set of verification test prob...
Article
Full-text available
This erratum concerns Figure 9 of the original article in which the line delimiting two effect types ("Permanent hearing loss increasingly likely" and "Permanent hearing loss very likely") was misplaced. This error, which has now been corrected, affects neither the main text nor the conclusion of the study. The authors apologize for the error.
Article
Full-text available
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 measurements en...
Article
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 spread...
Article
Full-text available
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 depe...
Technical Report
Vocabulary is the most basic of subjects for standardization. Without an accepted standard for the definition of terminology, the production of scientific and engineering publications in a technical area, including the development of standards for measurement, processing or modelling in that area, becomes a laborious and time-consuming task that wo...
Article
Toward the end of the First World War, Paul Langevin and Robert Boyles developed the first underwater echo-ranging systems capable of detecting and localizing submarines, with important consequences for the outcome of the Second World War. Their invention involved the use of quartztransducers for initial generation of sound and reception of the ech...
Article
Various models for the underwater noise radiation due to marine pile driving are being developed worldwide, to predict the sound exposure of marine life during pile driving activities. However, experimental validation of these models is scarce, especially for larger distances. Recently, TNO has been provided with data from underwaternoise measureme...
Article
Anthropogenic underwater sounds create a potential risk to aquatic organisms. Many regulators require this risk to be assessed before allowing a sound-producing activity to proceed. Regulators typically set allowable exposure criteria for a range of acoustic parameters and require the assessment to address whether a given acoustic metric would exce...
Article
In shallow water, active sonar performance is typically limited by reverberation, making the prediction of target echo and reverberation, and their ratio, an important part of sonar performance prediction. In range-dependent shallow water environments, these quantities are often calculated without considering the effect of dispersion. The effect of...
Article
In shallow water, active sonar performance is typically limited by reverberation, making the prediction of target echo, reverberation, and echo-to-reverberation ratio an important part of sonar performance prediction. In range-dependent shallow-water environments, the echo is often calculated without considering the effect of dispersion, and reverb...
Conference Paper
Anthropogenic underwater sounds represent a potential risk to aquatic organisms. Many regulators require this risk to be assessed before allowing a sound-producing activity to proceed. Regulators typically set exposure criteria for a range of acoustic parameters and require the assessment to address whether a given acoustic metric would exceed a sp...
Article
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 localize objects submerged in seawater. The efficacy of the sonar equations, with individual terms evaluated in decibels, is well established in Earth's oceans. The sona...
Article
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 generated...
Article
Full-text available
The prediction of underwater noise emissions from impact pile driving during near-shore and offshore construction activities and its potential effect on the marine environment has been a major field of research for several years. A number of different modeling approaches have been suggested recently to predict the radiated sound pressure at differe...
Conference Paper
The potential impact of seismic surveys on marine life has given regulators and scientists a shared interest in quantifying the sound field radiated by airgun arrays. Predictions do not always agree well with measurements, and there is a need to build confidence in model accuracy. To address this need, experts in airgun sound fieldmodeling were inv...
Article
Full-text available
Large amounts of legacy unexploded ordnance (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 detona...
Article
In mitigating the risk of sonar operations, the behavioral response of cetaceans is one of the major knowledge gaps that needs to be addressed. The 3S-Project has conducted a number of controlled exposure experiments with a realistic sonar source in Norwegian waters from 2006 to 2013. In total, the following six target species have been studied: ki...
Article
Full-text available
The European Union requires member states to achieve or maintain good environmental status for their marine territorial waters and explicitly mentions potentially adverse effects of underwater sound. In this study, we focused on producing maps of underwater sound from various natural and anthropogenic origins in the Dutch North Sea. The source prop...
Article
Ramp-up procedures are used to mitigate the impact of sound on marine mammals. Sound exposure models combined with observations of marine mammals responding to sound can be used to assess the effectiveness of ramp-up procedures. We found that ramp-up procedures before full-level sonar operations can reduce the risk of hearing threshold shifts with...
Article
We estimated the long-range effects of air gun array noise on marine mammal communication ranges in the Southern Ocean. Air gun impulses are subject to significant distortion during propagation, potentially resulting in a quasi-continuous sound. Propagation modeling to estimate the received waveform was conducted. A leaky integrator was used as a h...
Article
Effects of noise on fish populations may be predicted by the population consequence of acoustic disturbance (PCAD) model. We have predicted the potential risk of population disturbance when the highest sound exposure level (SEL) at which adult herring do not respond to naval sonar (SEL0) is exceeded. When the population density is low (feeding), th...
Technical Report
Full-text available
The European Marine Strategy Framework Directive requires European member states to develop strategies for their marine waters leading to programs of measures that achieve or maintain good environmental status (GES) in all European seas by 2020. An essential step toward reaching GES is the establishment of monitoring programs, enabling the state of...
Conference Paper
As concern about anthropogenic noise and its impacts on marine fauna is increasing around the globe, data are being compared across populations, species, noise sources, geographic regions, and time. However, much of the raw and processed data are not comparable due to differences in measurement methodology, analysis and reporting, and a lack of met...
Article
Full-text available
The underwater sound produced during construction of the Port of Rotterdam harbor extension (Maasvlakte 2) was measured, with emphasis on the contribution of the trailing suction hopper dredgers during their various activities: dredging, transport, and discharge of sediment. Measured source levels of the dredgers, estimated source levels of other s...
Article
Because of the history of sonar and sonar engineering, the concept of "source level" is widely used to characterize anthropogenic sound sources, but is it useful for sources other than sonar transmitters? The concept and applicability of source level are reviewed for sonar, air guns, explosions, ships, and pile drivers. International efforts toward...
Article
The requirement by modern navies to predict sonar performance in shallow water, whether for use in research, planning or operations, led to an initiative for the validation of reverberation models in the form of two Reverberation Modeling Workshops at the University of Texas at Austin in November 2006 and May 2008 [J. S. Perkins and E. I. Thorsos,...
Conference Paper
Full-text available
Seismic exploration has the potential to make a significant contribution to the soundscape of the North Sea. An airgun works by rapid release of air into water, forming a large bubble, which then pulsates, radiating sound as the bubble successively compresses and rarefies the surrounding water. An airgun array source signature model is described, f...
Conference Paper
Full-text available
The SONIC (Suppression Of underwater Noise Induced by Cavitation) and AQUO (Achieve QUieter Oceans by shipping noise footprint reduction) projects were awarded withinthe European Seventh Framework Program to develop tools to investigate and mitigate the effects of underwater sound generated by shipping activities on marine life. Model generated sou...
Article
Full-text available
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 reverbera...
Article
Active sonar performance is determined by the characteristics of the target, the sonar system and the effect of the environment on the received waveform. The two main influences of the environment are propagation effects and the contamination of the target echo with a background. The ambient noise and reverberation are mitigated by means of signal...
Article
The International System of Quantities (ISQ), incorporating definitions of physical quantities and their units, was completed in 2009 following an extensive collaboration between two major international standards organizations, the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC). The ISQ...
Article
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 distinguish the echolocation clicks from the background. To avoid a bias in the estimated population density, this method relie...
Article
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 functio...
Conference Paper
Full-text available
Accurate and fast estimation of propagation loss (PL) is needed for simulations of sonar or acoustic communication performance, and for environmental risk assessment. Accurate calculation of PL in range dependent and lossy waveguides can require computationally expensive wave theory techniques. In this work, a new propagation model is introduced fo...
Article
Full-text available
Pile driving as used for in-water construction can produce high levels of underwater sound that has potential to produce physiological and/or behavioral effects on fish, benthic invertebrates, and marine mammals. There are two basic pile driving methods: impact pile driving where the pile is driven by strikes from a high-energy hammer, and vibrator...