An estimation of buoyancy flux for a mixture of turbulence and double diffusion
An estimation of buoyancy flux for a mixture of turbulence and double diffusion
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DOI：
10.1175/jpo2996.1
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发表时间：
2007-03-01
影响因子：
3.5
通讯作者：
Yoshida, Jiro
中科院分区：
文献类型：
--
作者：
Inoue, Ryuichiro;Yamazaki, Hidekatsu;Yoshida, Jiro
本文对黑潮/黑潮/津轻流系混合水域的微结构进行了测量。虽然强烈的湍流附近的正面之间的Oyashio和津轻电流，双扩散占据了显着的份额在津轻水和混合水之间的Oyashio和黑潮。在确定了区分双扩散和湍流的标准后，利用微结构数据估算了垂直扩散系数和浮力通量。当湍流较弱时，在温度和盐度异常周围观察到双扩散，部分原因是交错，并主导浮力通量。由于双扩散的垂直扩散系数被参数化为10米尺度密度比的函数。10米尺度的扩散率估计是一致的微观结构的数据时，一个适当的标准，以重现概率密度函数的特纳角被应用。提出了一个加权平均扩散率模型，以适当考虑湍流和双扩散的同时。
Microstructure measurements were made in the Mixed Water Region of the Oyashio/Kuroshio/Tsugaru currents system where both turbulence and double diffusion are involved in mixing. While intense turbulence is observed near the front between the Oyashio and the Tsugaru Current, double diffusion occupies a noticeable fraction in both the Tsugaru Water and the Mixed Water between the Oyashio and the Kuroshio. After determining a criterion to distinguish double diffusion from turbulence, vertical diffusivities and buoyancy fluxes are estimated using microstructure data. When turbulence is weak, double diffusion is observed around temperature and salinity anomalies, partly due to interleaving, and dominates the buoyancy flux. Vertical diffusivities due to double diffusion are parameterized as a function of the 10-m-scale density ratio. The 10-m-scale diffusivity estimates are consistent with the microstructure data when an appropriate criterion to reproduce a probability density function for the Turner angle is applied. A weighted-average diffusivity model is proposed to account properly for turbulence and double diffusion simultaneously.