Observations of sound-speed fluctuations in the Beaufort Sea from Summer 2016 to Summer 2017
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Authors
Kucukosmanoglu, Murat
Colosi, John A.
Worcester, Peter F.
Dzieciuch, Matthew A.
Torres, Daniel J.
Subjects
Advisors
Date of Issue
2021-03
Date
2021-03
Publisher
Acoustical Society of America
Language
Abstract
Due to seasonal ice cover, acoustics can provide a unique means for Arctic undersea communication, navigation, and remote sensing. This study seeks to quantify the annual cycle of the thermohaline structure in the Beaufort Sea and characterize acoustically relevant oceanographic processes such as eddies, internal waves, near-inertial waves (NIWs), and spice. The observations are from a seven-mooring, 150-km radius acoustic transceiver array equipped with oceanographic sensors that collected data in the Beaufort Sea from 2016 to 2017. Depth and time variations of the sound speed are analyzed using isopycnal displacements, allowing a separation of baroclinic processes and spice. Compared to lower latitudes, the overall sound speed variability is small with a maximum root mean square of 0.6 m/s. The largest source of variability is spice, most significant in the upper 100 m, followed by eddies and inter- nal waves. The displacement spectrum in the internal wave band is time dependent and different from the Garret- Munk (GM) spectrum. The internal wave energy varied with time averaging 5% of the GM spectrum. The spice sound-speed frequency spectrum has a form very different from the displacement spectrum, a result not seen at lower latitudes. Because sound speed variations are weak, observations of episodic energetic NIWs with horizontal cur- rents up to 20 cm/s have potential acoustical consequences.
Type
Article
Description
17 USC 105 interim-entered record; under review.
The article of record as published may be found at https://doi.org/10.1121/10.0003601
The article of record as published may be found at https://doi.org/10.1121/10.0003601
Series/Report No
Department
Oceanography
Organization
Naval Postgraduate School (U.S.)
Identifiers
NPS Report Number
Sponsors
Funder
This research was supported by the Office of Naval Research (ONR) and M.K. was supported by an ONR Ocean Acoustics Graduate Student Fellowship under Award No. N00014-19-1-2203. The 600kHz ADCP and IPS ice draft data were supported by the ONR Arctic and Global Prediction Program (ONR 322AG) under Award No. N00014-15-1-2782. This material is based on work supported by the ONR under Award No. N00014-15-2068
Format
13 p.
Citation
Kucukosmanoglu, Murat, et al. "Observations of sound-speed fluctuations in the Beaufort Sea from summer 2016 to summer 2017." The Journal of the Acoustical Society of America 149.3 (2021): 1536-1548.
Distribution Statement
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.