Colosi John A, Zinicola-Lapin William
Department of Oceanography, Naval Postgraduate School, Monterey, California 93943, USA.
J Acoust Soc Am. 2021 Mar;149(3):1969. doi: 10.1121/10.0003821.
Here, the problem of mode coupling in a mixed layer (ML) surface duct is considered where the coupling is induced by deterministic upper ocean features such as eddies, filaments, and/or density compensated temperature and salinity anomalies (spice). The single scatter Dyson series solution for mode energy is used to define a non-dimensional mode interaction parameter Γ that quantifies the strength of coupling between modes m and n as a function of environmental factors and frequency. Direct coupled mode simulations at 400 and 1000 Hz show weak, first order coupling and small ML transmission loss (TL) variability when Γ<1, while for Γ>1, there is strong, higher order coupling with large changes in ML TL. Importantly, there is a frequency dependent resonance condition associated with the range width of the perturbations, Δ, such that Γ→0 as Δ→0 and ∞.
在此，我们考虑混合层（ML）表面波导中的模式耦合问题，其中耦合是由确定性的上层海洋特征引起的，如涡旋、细丝和/或密度补偿温度和盐度异常（香料）。用于模式能量的单散射戴森级数解被用来定义一个无量纲模式相互作用参数Γ，它作为环境因素和频率的函数来量化模式m和n之间的耦合强度。在400和1000赫兹下的直接耦合模式模拟表明，当Γ<1时，存在弱的一阶耦合和小的混合层传输损耗（TL）变化，而当Γ>1时，存在强的高阶耦合，混合层TL有很大变化。重要的是，存在一个与扰动范围宽度Δ相关的频率相关共振条件，使得当Δ→0和∞时，Γ→0。
