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Ocean Noise

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https://www.readbyqxmd.com/read/28389569/parallel-adaptive-evolution-of-geographically-distant-herring-populations-on-both-sides-of-the-north-atlantic-ocean
#1
Sangeet Lamichhaney, Angela P Fuentes-Pardo, Nima Rafati, Nils Ryman, Gregory R McCracken, Christina Bourne, Rabindra Singh, Daniel E Ruzzante, Leif Andersson
Atlantic herring is an excellent species for studying the genetic basis of adaptation in geographically distant populations because of its characteristically large population sizes and low genetic drift. In this study we compared whole-genome resequencing data of Atlantic herring populations from both sides of the Atlantic Ocean. An important finding was the very low degree of genetic differentiation among geographically distant populations (fixation index = 0.026), suggesting lack of reproductive isolation across the ocean...
April 7, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28372102/bowhead-whale-localization-using-time-difference-of-arrival-data-from-asynchronous-recorders
#2
Graham A Warner, Stan E Dosso, David E Hannay
This paper estimates bowhead whale locations and uncertainties using nonlinear Bayesian inversion of the time-difference-of-arrival (TDOA) of low-frequency whale calls recorded on onmi-directional asynchronous recorders in the shallow waters of the northeastern Chukchi Sea, Alaska. A Y-shaped cluster of seven autonomous ocean-bottom hydrophones, separated by 0.5-9.2 km, was deployed for several months over which time their clocks drifted out of synchronization. Hundreds of recorded whale calls are manually associated between recorders...
March 2017: Journal of the Acoustical Society of America
https://www.readbyqxmd.com/read/28372041/vertical-line-array-measurements-of-ambient-noise-in-the-north-pacific
#3
Mehdi Farrokhrooz, Kathleen E Wage, Matthew A Dzieciuch, Peter F Worcester
Shipping noise and wind are the dominant sources of ocean noise in the frequency band between 20 and 500 Hz. This paper analyzes noise in that band using data from the SPICEX experiment, which took place in the North Pacific in 2004-2005, and compares the results with other North Pacific experiments. SPICEX included vertical arrays with sensors above and below the surface conjugate depth, facilitating an analysis of the depth dependence of ambient noise. The paper includes several key results. First, the 2004-05 noise levels at 50 Hz measured in SPICEX had not increased relative to levels measured by Morris [(1978)...
March 2017: Journal of the Acoustical Society of America
https://www.readbyqxmd.com/read/28345033/improved-estimates-of-ocean-heat-content-from-1960-to-2015
#4
Lijing Cheng, Kevin E Trenberth, John Fasullo, Tim Boyer, John Abraham, Jiang Zhu
Earth's energy imbalance (EEI) drives the ongoing global warming and can best be assessed across the historical record (that is, since 1960) from ocean heat content (OHC) changes. An accurate assessment of OHC is a challenge, mainly because of insufficient and irregular data coverage. We provide updated OHC estimates with the goal of minimizing associated sampling error. We performed a subsample test, in which subsets of data during the data-rich Argo era are colocated with locations of earlier ocean observations, to quantify this error...
March 2017: Science Advances
https://www.readbyqxmd.com/read/28298467/swimming-and-diving-energetics-in-dolphins-a-stroke-by-stroke-analysis-for-predicting-the-cost-of-flight-responses-in-wild-odontocetes
#5
Terrie M Williams, Traci L Kendall, Beau P Richter, Courtney R Ribeiro-French, Jason S John, Kim L Odell, Barbara A Losch, David A Feuerbach, M Andrew Stamper
Exponential increases in hydrodynamic drag and physical exertion occur when swimmers move quickly through water, and underlie the preference for relatively slow routine speeds by marine mammals regardless of body size. Because of this and the need to balance limited oxygen stores when submerged, flight (escape) responses may be especially challenging for this group. To examine this, we used open-flow respirometry to measure the energetic cost of producing a swimming stroke during different levels of exercise in bottlenose dolphins (Tursiops truncatus)...
March 15, 2017: Journal of Experimental Biology
https://www.readbyqxmd.com/read/28289557/acoustic-monitoring-indicates-a-correlation-between-calling-and-spawning-in-captive-spotted-seatrout-cynoscion-nebulosus
#6
Eric W Montie, Matt Hoover, Christopher Kehrer, Justin Yost, Karl Brenkert, Tim O'Donnell, Michael R Denson
BACKGROUND: Fish sound production is widespread throughout many families. Territorial displays and courtship are the most common reasons for fish sound production. Yet, there is still some questions on how acoustic signaling and reproduction are correlated in many sound-producing species. In the present study, our aim was to determine if a quantitative relationship exists between calling and egg deposition in captive spotted seatrout (Cynoscion nebulosus). This type of data is essential if passive acoustics is to be used to identify spawning aggregations over large spatial scales and monitor reproductive activity over annual and decadal timeframes...
2017: PeerJ
https://www.readbyqxmd.com/read/28273800/isar-imaging-of-ship-targets-based-on-an-integrated-cubic-phase-bilinear-autocorrelation-function
#7
Jibin Zheng, Hongwei Liu, Zheng Liu, Qing Huo Liu
For inverse synthetic aperture radar (ISAR) imaging of a ship target moving with ocean waves, the image constructed with the standard range-Doppler (RD) technique is blurred and the range-instantaneous-Doppler (RID) technique has to be used to improve the image quality. In this paper, azimuth echoes in a range cell of the ship target are modeled as noisy multicomponent cubic phase signals (CPSs) after the motion compensation and a RID ISAR imaging algorithm is proposed based on the integrated cubic phase bilinear autocorrelation function (ICPBAF)...
March 3, 2017: Sensors
https://www.readbyqxmd.com/read/28253650/blind-deconvolution-of-shipping-sources-in-an-ocean-waveguide
#8
Sung-Hoon Byun, Christopher M A Verlinden, Karim G Sabra
This paper investigates the applicability of a ray-based blind deconvolution (RBD) method for underwater acoustic sources of opportunity such as ships recorded on a receiver array. The RBD relies on first estimating the unknown phase of the random source by beamforming along a well-resolved ray path, and then matched-filtering each received signal using the knowledge of this random phase to estimate the full channel impulse responses (CIRs) between the unknown source and the array elements (up to an arbitrary time-shift) as well as recovering the radiated signal by the random source...
February 2017: Journal of the Acoustical Society of America
https://www.readbyqxmd.com/read/28147624/localizing-scatterers-from-surf-noise-cross-correlations
#9
Jie Li, Peter Gerstoft, Dazhi Gao, Guofu Li, Ning Wang
The backscattered travel-time structure is obtained by cross-correlating air-acoustic ocean surf noise recorded on microphone pairs (separation ∼2 m) on the beach. The scatterer is a 20 cm radius Polyvinyl chloride pipe 2.5 m landside of the microphone array. Arrivals corresponding to the time-difference (travel-time difference between two scatterer-receiver paths) and scattered (travel time for receiver-scatterer-receiver path) waves emerge in the cross-correlation functions in a backscattering configuration...
January 2017: Journal of the Acoustical Society of America
https://www.readbyqxmd.com/read/28147605/adaptive-frequency-difference-matched-field-processing-for-high-frequency-source-localization-in-a-noisy-shallow-ocean
#10
Brian M Worthmann, H C Song, David R Dowling
Remote source localization in the shallow ocean at frequencies significantly above 1 kHz is virtually impossible for conventional array signal processing techniques due to environmental mismatch. A recently proposed technique called frequency-difference matched field processing (Δf-MFP) [Worthmann, Song, and Dowling (2015). J. Acoust. Soc. Am. 138(6), 3549-3562] overcomes imperfect environmental knowledge by shifting the signal processing to frequencies below the signal's band through the use of a quadratic product of frequency-domain signal amplitudes called the autoproduct...
January 2017: Journal of the Acoustical Society of America
https://www.readbyqxmd.com/read/28147571/active-wideband-higher-order-raypath-separation-in-multipath-environment
#11
Longyu Jiang, Yaping Hong, Philippe Roux, Jiasong Wu, Huazhong Shu
Multiple raypaths propagation is caused by reflection and refraction at the surface and the bottom of the water column. In this study, an active wideband higher-order separation is proposed, which enables the separation of raypaths interrupted by colored noise (as traditionally found in ocean environments) in the angle-vs-time domain. A comparative study shows that the proposed algorithm achieves a more accurate separation than other algorithms. Moreover, with the proposed approach, it is not necessary to assume that the number of sensors is larger than that of the sources...
January 2017: Journal of the Acoustical Society of America
https://www.readbyqxmd.com/read/28076360/consequences-of-global-warming-of-1-5-%C3%A2-c-and-2-%C3%A2-c-for-regional-temperature-and-precipitation-changes-in-the-contiguous-united-states
#12
Ambarish V Karmalkar, Raymond S Bradley
The differential warming of land and ocean leads to many continental regions in the Northern Hemisphere warming at rates higher than the global mean temperature. Adaptation and conservation efforts will, therefore, benefit from understanding regional consequences of limiting the global mean temperature increase to well below 2°C above pre-industrial levels, a limit agreed upon at the United Nations Climate Summit in Paris in December 2015. Here, we analyze climate model simulations from the Coupled Model Intercomparison Project Phase 5 (CMIP5) to determine the timing and magnitude of regional temperature and precipitation changes across the contiguous United States (US) for global warming of 1...
2017: PloS One
https://www.readbyqxmd.com/read/28040049/ambient-noise-correlations-on-a-mobile-deformable-array
#13
Perry Naughton, Philippe Roux, Riley Yeakle, Curt Schurgers, Ryan Kastner, Jules S Jaffe, Paul L D Roberts
This paper presents a demonstration of ambient acoustic noise processing on a set of free floating oceanic receivers whose relative positions vary with time. It is shown that it is possible to retrieve information that is relevant to the travel time between the receivers. With thousands of short time cross-correlations (10 s) of varying distance, it is shown that on average, the decrease in amplitude of the noise correlation function with increased separation follows a power law. This suggests that there may be amplitude information that is embedded in the noise correlation function...
December 2016: Journal of the Acoustical Society of America
https://www.readbyqxmd.com/read/28040020/effect-of-dispersion-on-the-convergence-rate-for-green-s-function-retrieval
#14
John Y Yoritomo, Richard L Weaver
Much information about wave propagation in a variety of structures has been obtained from Green's function retrieval by noise correlation. Here it is examined how dispersion affects Green's function retrieval and, in particular, its signal-to-noise ratio (SNR). On recalling how the inherent spread of a signal due to band limitation is augmented by spread due to dispersion and propagation distance, and how both affect amplitude, it is argued that SNR in highly dispersive media can be substantially lowered by strong dispersion...
December 2016: Journal of the Acoustical Society of America
https://www.readbyqxmd.com/read/28036011/a-fiber-optic-interferometric-tri-component-geophone-for-ocean-floor-seismic-monitoring
#15
Jiandong Chen, Tianying Chang, Qunjian Fu, Jinpeng Lang, Wenzhi Gao, Zhongmin Wang, Miao Yu, Yanbo Zhang, Hong-Liang Cui
For the implementation of an all fiber observation network for submarine seismic monitoring, a tri-component geophone based on Michelson interferometry is proposed and tested. A compliant cylinder-based sensor head is analyzed with finite element method and tested. The operation frequency ranges from 2 Hz to 150 Hz for acceleration detection, employing a phase generated carrier demodulation scheme, with a responsivity above 50 dB re rad/g for the whole frequency range. The transverse suppression ratio is about 30 dB...
December 28, 2016: Sensors
https://www.readbyqxmd.com/read/28000727/evidence-of-cnidarians-sensitivity-to-sound-after-exposure-to-low-frequency-noise-underwater-sources
#16
Marta Solé, Marc Lenoir, José Manuel Fontuño, Mercè Durfort, Mike van der Schaar, Michel André
Jellyfishes represent a group of species that play an important role in oceans, particularly as a food source for different taxa and as a predator of fish larvae and planktonic prey. The massive introduction of artificial sound sources in the oceans has become a concern to science and society. While we are only beginning to understand that non-hearing specialists like cephalopods can be affected by anthropogenic noises and regulation is underway to measure European water noise levels, we still don't know yet if the impact of sound may be extended to other lower level taxa of the food web...
December 21, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27914437/humpback-whale-generated-ambient-noise-levels-provide-insight-into-singers-spatial-densities
#17
Kerri D Seger, Aaron M Thode, Jorge Urbán-R, Pamela Martínez-Loustalot, M Esther Jiménez-López, Diana López-Arzate
Baleen whale vocal activity can be the dominant underwater ambient noise source for certain locations and seasons. Previous wind-driven ambient-noise formulations have been adjusted to model ambient noise levels generated by random distributions of singing humpback whales in ocean waveguides and have been combined to a single model. This theoretical model predicts that changes in ambient noise levels with respect to fractional changes in singer population (defined as the noise "sensitivity") are relatively unaffected by the source level distributions and song spectra of individual humpback whales (Megaptera novaeangliae)...
September 2016: Journal of the Acoustical Society of America
https://www.readbyqxmd.com/read/27914391/frequency-based-noise-coherence-function-extension-and-application-to-passive-bottom-loss-estimation
#18
Lanfranco Muzi, Martin Siderius, Peter L Nielsen
Accurate modeling of acoustic propagation in the ocean waveguide is important to SONAR-performance prediction. Particularly in shallow waters, a crucial contribution to the total transmission loss is the bottom refection loss, which can be estimated passively by beamforming the natural surface-noise acoustic field recorded by a vertical line array of hydrophones. However, the performance in this task of arrays below 2 m of length is problematic for frequencies below 10 kHz It is shown in this paper that, when the data are free of interference from sources other than wind and wave surface noise, data from a shorter array can be used to approximate the coherence function of a longer array...
September 2016: Journal of the Acoustical Society of America
https://www.readbyqxmd.com/read/27807249/singing-whales-generate-high-levels-of-particle-motion-implications-for-acoustic-communication-and-hearing
#19
T Aran Mooney, Maxwell B Kaplan, Marc O Lammers
Acoustic signals are fundamental to animal communication, and cetaceans are often considered bioacoustic specialists. Nearly all studies of their acoustic communication focus on sound pressure measurements, overlooking the particle motion components of their communication signals. Here we characterized the levels of acoustic particle velocity (and pressure) of song produced by humpback whales. We demonstrate that whales generate acoustic fields that include significant particle velocity components that are detectable over relatively long distances sufficient to play a role in acoustic communication...
November 2016: Biology Letters
https://www.readbyqxmd.com/read/27770981/marine-mammals-in-the-mediterranean-sea-an-overview
#20
G Notarbartolo di Sciara
Despite being a small part of the world's oceans, the Mediterranean Sea hosts a diverse marine mammal fauna, with a total of 28 different species known to occur, or to have occurred, in the region. Species currently recognised as regular in the Mediterranean-the Mediterranean monk seal (Monachus monachus) and 11 cetaceans (fin whale, Balaenoptera physalus; sperm whale, Physeter macrocephalus; Cuvier's beaked whale, Ziphius cavirostris; short-beaked common dolphin, Delphinus delphis; long-finned pilot whale, Globicephala melas; Risso's dolphin, Grampus griseus; killer whale, Orcinus orca; striped dolphin, Stenella coeruleoalba; rough-toothed dolphin, Steno bredanensis; common bottlenose dolphin, Tursiops truncatus; harbour porpoise, Phocoena phocoena relicta) have adapted well to the region's environmental conditions, but their coexistence with humans is problematic...
2016: Advances in Marine Biology
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