Mixing and Diapycnal Advection in the Ocean
Mixing and Diapycnal Advection in the Ocean
复制标题
海洋中的混合和二重平流
DOI：
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
R. Schmitt
中科院分区：
文献类型：
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作者：
Louis Laurent;J. Toole;R. Schmitt
摘要：在分层海洋中，垂直运动由绝热和非绝热机制引起。双重平流是流过等密度表面的垂直分量，当混合产生浮力发散通量时发生。当底密度平流速率随深度变化时，会发生涡旋拉伸对侧流的浮力强迫。提出了粗糙地形上方增强湍流的微观结构观察。这些数据使我们能够区分非绝热强迫对循环的影响。对非密平流的估计用于量化非绝热流，并评估了非密平流作为循环中涡旋拉伸机制的作用。研究发现，二重质量通量的发散是发生在断裂带地形上方的环流的重要强迫机制。此外，二重平流的方向和大小都取决于湍流产生浮力通量的效率。斜流平流的深度变化表明，弱层状深渊峡谷中的混合效率降低。
Abstract : In the stratified ocean, vertical motions arise from both adiabatic and diabatic mechanisms. Diapycnal advection is the vertical component of flow across an isopycnal surface which occurs when mixing produces a divergent flux of buoyancy. Buoyancy forcing of the lateral flow by vortex stretching occurs when diapycnal advection rates vary with depth. Microstructure observations of enhanced turbulence above rough topography are presented. These data allow us to distinguish the influence of diabatic forcing on the circulation. Estimates of diapycnal advection are used to quantify the diabatic flow, and the role of diapycnal advection as a mechanism of vortex stretching on the circulation is assessed. The divergence of diapycnal mass flux is found to be a significant forcing mechanism for the circulation occurring above fracture zone topography. Moreover, both the direction and magnitude of diapycnal advection are dependent on the efficiency of turbulence at generating a buoyancy flux. Depth variations of diapycnal advection suggest the mixing efficiency is reduced in weakly stratified abyssal canyons.