Shear instability is a dominant mechanism for mixing in the stratified oceans and coastal seas. For the first time, we present fine-scale, direct measurements of shear instabilities in the bottom front generated by the Kuroshio intrusion into the Changjiang (Yangtze) river plume. Shear instabilities were identified using a shipboard echo-sounder and the resulting turbulent mixing was quantified using a turbulence microstructure profiler. The shear instabilities generate vigorous turbulent mixing with dissipation rate and vertical diffusivity up to O (10⁻⁴ m² s⁻³) and O (10⁻¹ m² s⁻¹), respectively, comparable to values associated with shear instabilities observed in river plumes and western boundary currents but several orders of magnitude larger than typical values in the open ocean. The enhanced turbulence may contribute significantly to mixing between the Kuroshio water and coastal water and thereby alter the coastal biogeochemistry cycles.

中文翻译：

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黑潮侵入长江羽流的剪切失稳和湍流混合


剪切不稳定性是分层海洋和沿海海混合的主要机制。我们首次提出了由 Kuroshio 侵入长江（长江）羽流产生的底部前沿剪切不稳定性的精细、直接测量。使用船载回声测深仪识别剪切不稳定性，并使用湍流微观结构剖面仪量化由此产生的湍流混合。剪切不稳定性会产生剧烈的湍流混合，耗散速率和垂直扩散率分别高达 O （10-4 m^{2 s-3}） 和 O （^10-1 m^{2 s-1}），与在河流羽流和西部边界流中观察到的剪切不稳定性相关的值相当，但比开阔海洋中的典型值大几个数量级。增强的湍流可能显着促进黑潮水和沿海水之间的混合，从而改变沿海生物地球化学循环。