Formation of coastal fog was observed near the southern tip of Nova Scotia when warm, humid air was advected towards the shore over an area of colder water. The sea-surface temperature in the colder and higher salinity patch near the coast was below 14 °C compared to that of the surrounding sea of ≈ 17–18 °C. Measurements of stratification, currents, and the dissipation rate of turbulence kinetic energy (ε) on the Nova Scotia shelf, shelf break, and continental slope revealed the frequent occurrence of shear instability in the pycnocline. The probability of the gradient Richardson number (Ri)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$(Ri)$$\end{document} being less than a critical value of Ricr=0.25\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$Ri_{cr} = 0.25$$\end{document} in the depth range 30–90 m exceeded 50% on the shelf and over the slope, and it was above 75% along the shelf break, while in the open ocean pycnocline the probability of Ri<0.25\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$Ri < 0.25$$\end{document} is below 5%. The cumulative distribution functions of the dissipation rate in the pycnocline south-east of Nova Scotia followed the Burr probability model with median values from 7.9×10-9\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$7.9 \times 10^{ - 9}$$\end{document} W kg−1 on the slope to 1.9×10-8\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$1.9 \times 10^{ - 8}$$\end{document} W kg−1 at the shelf break. The eddy diffusivity (KN\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$K_{N}$$\end{document}) estimates follow a generalized extreme value distribution with a high median value of KN=5.8×10-5\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\left\langle {K_{N} } \right\rangle = 5.8 \times 10^{ - 5}$$\end{document} m2 s−1 at the shelf break. The diffusivity KN\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$K_{N}$$\end{document} depended on Ri\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$Ri$$\end{document} in general agreement with the parametrization previously suggested by Lozovatsky and Fernando (Philos Trans R Soc A 371:20120213, 2013) but with a higher level of mixing at Ri>1\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$Ri > 1$$\end{document}. This could be relevant to the nature of turbulence generation near the shelf break by random wave instabilities in the pycnocline at high Richardson and high Reynolds numbers.

中文翻译：

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新斯科舍东南部大陆架断裂附近的海洋湍流和混合

当温暖潮湿的空气在较冷的水域上平流向海岸时，在新斯科舍省南端附近观察到沿海雾的形成。与周围海域的 ≈ 17–18 °C 相比，靠近海岸的较冷和较高盐度斑块的海面温度低于 14 °C。对新斯科舍大陆架、大陆架断裂和大陆坡的分层、水流和湍流动能 (ε) 耗散率的测量表明，在后斜层经常发生剪切失稳。25\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin} {-69pt} \begin{document}$$Ri < 0.25$$\end{document} 低于 5%。新斯科舍省东南部pycnocline耗散率的累积分布函数遵循Burr概率模型，中值为7.9×10-9\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\ usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$7.9 \times 10^{ - 9}$ $\end{document} W kg−1 到 1 的斜率。9×10-8\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength {\oddsidemargin}{-69pt} \begin{document}$$1.9 \times 10^{ - 8}$$\end{document} W kg−1 在货架断裂处。涡流扩散系数 (KN\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength {\oddsidemargin}{-69pt} \begin{document}$$K_{N}$$\end{document}) 估计遵循广义极值分布，其中值 KN=5。1\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin} {-69pt} \begin{document}$$Ri > 1$$\end{document}。这可能与在高理查森数和高雷诺数下的密斜层中随机波不稳定性在陆架断裂附近产生湍流的性质有关。