Kucukosmanoglu Murat, Colosi John A, Worcester Peter F, Dzieciuch Matthew A, Torres Daniel J
Department of Ocean Sciences, University of California, Santa Cruz, California 95060, USA.
Department of Oceanography, Naval Postgraduate School, Monterey, California 93943, USA.
J Acoust Soc Am. 2021 Mar;149(3):1536. doi: 10.1121/10.0003601.
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 internal 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 currents up to 20 cm/s have potential acoustical consequences.
由于季节性海冰覆盖，声学可为北极海底通信、导航和遥感提供一种独特手段。本研究旨在量化波弗特海温盐结构的年周期，并描述与声学相关的海洋学过程，如涡旋、内波、近惯性波（NIWs）和盐度锋。观测数据来自一个半径150公里、由七个系泊点组成的声学收发器阵列，该阵列配备了海洋学传感器，于2016年至2017年在波弗特海收集数据。利用等密度面位移分析声速的深度和时间变化，从而分离斜压过程和盐度锋。与低纬度地区相比，整体声速变化较小，最大均方根为0.6米/秒。变化的最大来源是盐度锋，在100米上层最为显著，其次是涡旋和内波。内波带的位移谱随时间变化，与加勒特 - 蒙克（GM）谱不同。内波能量随时间变化，平均为GM谱的5%。盐度锋声速频谱的形式与位移谱非常不同，这一结果在低纬度地区未见。由于声速变化微弱，对水平流速高达20厘米/秒的间歇性高能近惯性波的观测可能会产生声学影响。
