Mixing in downslope flows in the ocean ‐ plumes versus gravity currents
Mixing in downslope flows in the ocean ‐ plumes versus gravity currents
复制标题
海洋中下坡流的混合——羽流与重力流
DOI：
10.3137/ao.460402
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发表时间：
2008
期刊：
影响因子：
1.2
通讯作者：
P. Baines
中科院分区：
文献类型：
--
作者：
P. Baines
摘要 描述了实验室实验揭示的流入分层环境的下坡流的性质，然后将结果应用于解释流入海洋的特定下坡流。在实验室中，非旋转下坡流可分为两种主要类型：在足够平缓的斜坡上的减阻重力流，其中密集下流的浮力主要由底部阻力来平衡；以及在足够陡的斜坡上的夹带羽流，其中浮力由来自上方的环境流体的强烈夹带来平衡。水流的混合特性由底部坡度、阻力系数和浮力数B=QN3/G2决定，其中Q和G是下流的体积通量和浮力，N是环境的浮力频率。这些实验可应用于海洋中流动与其横向压力梯度近似地转平衡的情况，并且参数应用于斜坡上的流动路径。提供了不同地点的许多下坡流的示例，包括红海流出、流入黑海和大西洋的地中海流出、丹麦海峡溢流和罗斯海流出。
Abstract The nature of downslope flows into stratified environments as revealed by laboratory experiments is described, and the results are then applied to interpret particular downslope flows into the ocean. In the laboratory, non‐rotating downslope flows can be divided into two main types: detraining gravity currents over sufficiently gentle slopes, where the buoyancy force of the dense downflow is mainly balanced by bottom drag, and entraining plumes over sufficiently steep slopes, where the buoyancy force is balanced by vigorous entrainment of environmental fluid from above. This mixing character of the flow is determined by the bottom slope, the drag coefficient and the buoyancy number B = QN3/G2, where Q and G are the volume flux and buoyancy of the down‐flow and N is the buoyancy frequency of the environment. These experiments may be applied to situations in the ocean where the flow is in approximate geostrophic balance with its transverse pressure gradient, and the parameters are applied to the flow path on the slope. Examples are provided for a number of downslope flows in various locations, including the Red Sea outflow, the Mediterranean outflow into the Black Sea and the Atlantic, the Denmark Strait overflow and the outflow from the Ross Sea.