Duda Timothy F, Zhang Weifeng Gordon, Lin Ying-Tsong
Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, USA.
J Acoust Soc Am. 2021 Apr;149(4):2117. doi: 10.1121/10.0003929.
A one-year fixed-path observation of seasonally varying subsurface ducted sound propagation in the Beaufort Sea is presented. The ducted and surface-interacting sounds have different time behaviors. To understand this, a surface-forced computational model of the Chukchi and Beaufort Seas with ice cover is used to simulate local conditions, which are then used to computationally simulate sound propagation. A sea ice module is employed to grow/melt ice and to transfer heat and momentum through the ice. The model produces a time- and space-variable duct as observed, with Pacific Winter Water (PWW) beneath a layer of Pacific Summer Water (PSW) and above warm Atlantic water. In the model, PSW moves northward from the Alaskan coastal area in late summer to strengthen the sound duct, and then mean PSW temperature decreases during winter and spring, reducing the duct effectiveness, one cause of a duct annual cycle. Spatially, the modeled PSW is strained and filamentary, with horizontally structured temperature. Sound simulations (order 200 Hz) suggest that ducting is interrupted by the intermittency of the PSW (duct gaps), with gaps enabling loss from ice cover (set constant in the sound model). The gaps and ducted sound show seasonal tendencies but also exhibit random process behavior.
本文介绍了对波弗特海季节性变化的次表层声道声传播进行的为期一年的固定路径观测。声道传播的声音和与海面相互作用的声音具有不同的时间特性。为了理解这一点，使用了一个带有冰盖的楚科奇海和波弗特海的表面强迫计算模型来模拟当地条件，然后用于计算模拟声音传播。采用一个海冰模块来使冰生长/融化，并通过冰传递热量和动量。该模型产生了一个如观测到的随时间和空间变化的声道，在一层太平洋夏季水（PSW）之下和温暖的大西洋水之上是太平洋冬季水（PWW）。在模型中，PSW在夏末从阿拉斯加沿海地区向北移动以加强声道，然后在冬季和春季PSW的平均温度下降，降低了声道的有效性，这是声道年周期的一个原因。在空间上，模拟的PSW是应变的且呈丝状，具有水平结构的温度。声音模拟（约200Hz）表明，声道传播被PSW的间歇性（声道间隙）打断，这些间隙使得声音能够从冰盖损失（在声音模型中设为常数）。这些间隙和声道传播的声音呈现出季节性趋势，但也表现出随机过程行为。
