A Simple Dynamical Model of the Warm-Water Branch of the Middepth Meridional Overturning Cell
A Simple Dynamical Model of the Warm-Water Branch of the Middepth Meridional Overturning Cell
复制标题
中深经向翻转单元温水支的简单动力学模型
DOI：
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
R. Samelson
中科院分区：
文献类型：
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作者：
R. Samelson
提出了一个在具有环极连接的矩形盆地中中层经向翻转环流暖水分支的弱重力模型。该模型描述了通过环极流的埃克曼平流产生暖水、通过向南穿过该流的涡通量消散暖水以及该流以北非绝热过程对暖水的净产生或消散之间的平衡。结果强调了东部边界条件在设定该流以北的温跃层结构以及风强迫、涡通量和非绝热混合之间的非线性相互作用中的作用，这些因素共同控制了模型经向翻转环流的结构和振幅。结果表明存在这样的解：穿过环极流的向北埃克曼输送完全由向南的涡通量补偿，并且该流以北的经向翻转完全由非绝热强迫和通过该层底部的内部上升流驱动。还表明存在其他解，其中中纬度进入暖层的内部上升流可忽略不计，并且经向翻转环流由一个连续的环流圈组成，该环流圈将穿过环极流的向北埃克曼输送所输送的流体通过中纬度带到北半球副极地环流，在那里它冷却并返回深处。结果强调，风驱动、涡通量和非绝热过程的耦合要素在中层经向翻转环流中错综复杂地交织在一起。
A reduced-gravity model is presented of the warm-water branch of the middepth meridional overturning circulation in a rectangular basin with a circumpolar connection. The model describes the balance between production of warm water by Ekman advection across the circumpolar current, dissipation of warm water by eddy fluxes southward across the current, and the net production or dissipation of warm water by diabatic processes north of the current. The results emphasize the role of the eastern boundary condition in setting the thermocline structure northofthe current andthe nonlinear interactions betweenwind forcing, eddyfluxes, and diabatic mixing, which together control the structure and amplitude of the model meridional overturning circulation. SolutionsareshowntoexistinwhichthenorthwardEkmantransportacrossthecircumpolarcurrent is completely compensated by southward eddy fluxes and the meridional overturning north of the current is entirely driven by diabatic forcing and interior upwelling through the base of the layer. Other solutions are shown to exist in which the interior upwelling into the warm layer at midlatitudes is negligible and the meridional overturning circulation consists of a continuous cell that carried the fluid delivered by the northward Ekman transport across the circumpolar current through midlatitudes to the Northern Hemisphere subpolar gyre, where it cools and returns todepth. The results emphasize that the coupled elements ofwind driving, eddy fluxes, and diabatic processes are inextricably intertwined in the middepth meridional overturning circulation.
机械驱动经向翻转环流与温盐强迫和多重平衡理论的协调
影响因子：
4.6
作者：
Johnson H
通讯作者：
Johnson H