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Acoustic recordings and modeling under seasonally varying sea ice.

https://arctichealth.org/en/permalink/ahliterature300423
Source
Sci Rep. 2019 Jun 06; 9(1):8323
Publication Type
Journal Article
Date
Jun-06-2019
Author
Michael D Collins
Altan Turgut
Richard Menis
Jeffrey A Schindall
Author Affiliation
Code 7160, Naval Research Laboratory, Washington, D.C., 20375, USA. michael.collins@nrl.navy.mil.
Source
Sci Rep. 2019 Jun 06; 9(1):8323
Date
Jun-06-2019
Language
English
Publication Type
Journal Article
Abstract
Acoustic data from the Canada Basin Acoustic Propagation Experiment are discussed. These recordings were obtained under seasonally varying sea ice to the north of Alaska during a period of 154 days. They contain signals from sources that were deployed at ranges of 17.5, 29.6, and 237.8?km and ambient sounds from marine mammals and ice-related events. After the area was covered with ice, the amplitude of receptions from the most distant source gradually decreased as scattering features on the underside of the ice developed during fracturing, drifting, ridging, and rafting events. Improvements are presented for an Arctic acoustic model that is based on the parabolic equation method, and the approach is applied to a problem in which variable ice thickness acts as a loss mechanism by scattering energy out of the waveguide. Some of the recordings have a harmonic signature that is believed to be associated with the resonances of ice floes rubbing together, but variations in the harmonics over short time scales cannot be explained in terms of the resonances of an isolated floe. This behavior may be related to the coupling of vibrations at contact points that vary during the relative motions of floes.
PubMed ID
31171818 View in PubMed
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Azimuthal and temporal sound fluctuations on the Chukchi continental shelf during the Canada Basin Acoustic Propagation Experiment 2017.

https://arctichealth.org/en/permalink/ahliterature307454
Source
J Acoust Soc Am. 2019 Dec; 146(6):EL530
Publication Type
Journal Article
Date
Dec-2019
Author
Mohsen Badiey
Lin Wan
Sean Pecknold
Altan Turgut
Author Affiliation
Department of Electrical and Computer Engineering, University of Delaware, Newark, Delaware 19716, USA.
Source
J Acoust Soc Am. 2019 Dec; 146(6):EL530
Date
Dec-2019
Language
English
Publication Type
Journal Article
Abstract
The Shallow Water Canada Basin Acoustic Propagation Experiment was conducted on the Chukchi Sea continental shelf from October 2016 to November 2017. The experimental goals were to access (1) long-range (basin-scale) and (2) short-range (shallow-water) spatial and temporal energy variation. This letter focuses on a 20-dB energy change of acoustic signals in the frequency band 700-1100?Hz from June to August 2017 occurring along two shallow-water tracks from a common source, correlated with the occurrence of an oceanographic event in the top 150-m water column due to a Pacific Water outflow from the Bering Sea and retreat of the Marginal Ice Zone.
PubMed ID
31893748 View in PubMed
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Temporal and spatial dependence of a yearlong record of sound propagation from the Canada Basin to the Chukchi Shelf.

https://arctichealth.org/en/permalink/ahliterature304683
Source
J Acoust Soc Am. 2020 09; 148(3):1663
Publication Type
Journal Article
Research Support, U.S. Gov't, Non-P.H.S.
Date
09-2020
Author
Megan S Ballard
Mohsen Badiey
Jason D Sagers
John A Colosi
Altan Turgut
Sean Pecknold
Ying-Tsong Lin
Andrey Proshutinsky
Richard Krishfield
Peter F Worcester
Matthew A Dzieciuch
Author Affiliation
Applied Research Laboratories, The University of Texas at Austin, Austin, Texas 78713, USA.
Source
J Acoust Soc Am. 2020 09; 148(3):1663
Date
09-2020
Language
English
Publication Type
Journal Article
Research Support, U.S. Gov't, Non-P.H.S.
Abstract
The Pacific Arctic Region has experienced decadal changes in atmospheric conditions, seasonal sea-ice coverage, and thermohaline structure that have consequences for underwater sound propagation. To better understand Arctic acoustics, a set of experiments known as the deep-water Canada Basin acoustic propagation experiment and the shallow-water Canada Basin acoustic propagation experiment was conducted in the Canada Basin and on the Chukchi Shelf from summer 2016 to summer 2017. During the experiments, low-frequency signals from five tomographic sources located in the deep basin were recorded by an array of hydrophones located on the shelf. Over the course of the yearlong experiment, the surface conditions transitioned from completely open water to fully ice-covered. The propagation conditions in the deep basin were dominated by a subsurface duct; however, over the slope and shelf, the duct was seen to significantly weaken during the winter and spring. The combination of these surface and subsurface conditions led to changes in the received level of the sources that exceeded 60 dB and showed a distinct spacio-temporal dependence, which was correlated with the locations of the sources in the basin. This paper seeks to quantify the observed variability in the received signals through propagation modeling using spatially sparse environmental measurements.
PubMed ID
33003894 View in PubMed
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