Generation and Propagation of M2 Internal Tides Modulated by the Kuroshio Northeast of Taiwan
Generation and Propagation of M2 Internal Tides Modulated by the Kuroshio Northeast of Taiwan
复制标题
台湾东北部黑潮调制的M-2内潮汐的产生与传播
DOI：
10.1029/2018jc014228
复制
发表时间：
2019-04-01
影响因子：
3.6
通讯作者：
Liu, Antony K.
中科院分区：
文献类型：
--
作者：
Chang, Hang;Xu, Zhenhua;Liu, Antony K.
本文利用高解析度数值模式，研究台湾东北黑潮中M-2内潮的产生与传播过程。波状大陆斜坡，特别是伊兰岭和勉华峡谷，首先被确定为M-2内部潮汐的能量源。黑潮影响下的区域一体化M-2正斜压转换速率约为2.35GW，其中伊兰岭约为0.9GW，闽华峡谷约为0.93GW，北陆架约为0.52GW。M-2内潮的产生受与黑潮有关的水平变化、纬向倾斜分层的影响。在这种情况下，与水平均匀分层开始的模拟相比，伊兰岭的转化率下降了30%左右，而在棉化峡谷和北陆架的转化率则增加了10%左右。来自多个源的内部潮汐相互干扰形成三维斜压场。来自闽华峡谷和北陆架的内潮的干涉被黑潮折射，呈现出中尺度的环流模式，这可以解释内孤立波的频繁发生。来自伊兰岭的沿坡潮汐束（TBKC）向南辐射，对抗北向的黑潮流，造成强烈的垂直位移，与最近报道的野外测量结果相比有利。M-2内部潮汐能主要在源点附近消散，剩余能量在有限距离内向外辐射。复杂的地形特征和背景流增强了内部的潮汐耗散，导致强烈的、不均匀的底流混合。
The variability and energetics of M-2 internal tides during their generation and propagation through the Kuroshio flows northeast of Taiwan are investigated using a high-resolution numerical model. The corrugated continental slopes, particularly the I-Lan Ridge and Mien-Hua Canyon, are first identified as the energetic sources of M-2 internal tides. The domain-integrated M-2 barotropic-to-baroclinic conversion rate under the Kuroshio influence is similar to 2.35GW, similar to 0.9GW of which is generated at the I-Lan Ridge, similar to 0.93GW at the Mien-Hua Canyon, and similar to 0.52GW at the north shelf. The M-2 internal tide generation is influenced by the horizontally varying, zonally tilting stratification associated with the Kuroshio. In this situation, the conversion rate decreases by similar to 30% at the I-Lan Ridge but increases to within similar to 10% at the Mien-Hua Canyon and north shelf, in comparison to the simulation initiated with horizontal homogeneous stratification. Internal tides from multiple sources interfere to form a three-dimensional baroclinic field. The interference by the internal tides from the Mien-Hua Canyon and north shelf is refracted by the Kuroshio and exhibits a mesoscale gyre pattern, which can explain the frequent occurrence of internal solitary waves. An energetic along-slope tidal beam (TBKC) from the I-Lan Ridge radiates southward against the northward Kuroshio flows, causing strong vertical displacement, which favorably compares with recently reported field measurements. The M-2 internal tide energy dissipates primarily near the source sites, and the remaining energy radiates outward over limited distances. Complex topographic features and background currents enhance the internal tide dissipation, which induces strong, inhomogeneous diapycnal mixing.