Separation of a Density Current from the Bottom of a Continental Slope
Separation of a Density Current from the Bottom of a Continental Slope
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密度流与大陆坡底部的分离
DOI：
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发表时间：
1998
期刊：
影响因子：
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通讯作者：
M. Stern
中科院分区：
文献类型：
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作者：
M. Stern
像墨西哥湾流这样的分层急流与大陆斜坡的分离涉及到连续的等轴面层从近乎水平的底部滑动到深海中相邻的近海等轴面。产生这种效应的一种机制是由于斜率等深线的下游收敛，如本文针对1层密度模型所示。在辐合的上游，假设了一股地转平衡急流，其近岸气旋性涡度区域位于大陆坡面上，近岸反气旋区位于重水上方的等周期界面上。对于O(1)Rossby数和横流地形变化，计算了下游地形缓慢变化时的恒定横流位移。对于“超临界”上游水流(即与自由地形波相比，速度较快)，坡外位移是由汇聚等深线产生的；对小幅度结果的外推表明，这一机制在数量上对沙尘暴具有重要意义。
Abstract Separation from the continental slope of stratified jets like the Gulf Stream involves the sliding of successive isopycnal layers from a nearly horizontal bottom to the adjacent offshore isopycnal in the deep ocean. One mechanism for producing such an effect is due to a downstream convergence of slope isobaths, as shown herein for a 1-layer density model. Upstream of the convergence, a geostrophically balanced jet is assumed with an inshore region of cyclonic vorticity resting on the continental slope and an offshore anticyclonic region resting on the isopycnal interface above heavier water. For O(1) Rossby number and cross-stream topographic variation, the steady transverse current displacements forced by slowly varying downstream topography are computed. For “supercritical” upstream flow (i.e., fast compared to free topographic waves) offslope displacements are produced by converging isobaths; extrapolation of the small amplitude result suggests that the mechanism is quantitatively important fo...