Eddy Cancellation of the Ekman Cell in Subtropical Gyres
Eddy Cancellation of the Ekman Cell in Subtropical Gyres
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DOI：
10.1175/jpo-d-16-0097.1
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发表时间：
2016-10
影响因子：
3.5
通讯作者：
E. Doddridge;D. Marshall;A. Hogg
中科院分区：
文献类型：
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作者：
E. Doddridge;D. Marshall;A. Hogg
摘要 与气候风应力旋度相关的大规模埃克曼抽吸的存在是副热带环流生物活动低的教科书解释。使用理想化的涡旋解析模型表明，欧拉平均埃克曼泵送可能会受到涡流驱动环流的反对，类似于大气费雷尔环流和南大洋迪肯环流受到涡流驱动环流的反对。拉格朗日粒子跟踪、位涡通量和深度密度流函数表明，在模型中，涡流的校正效应在很大程度上抵消了欧拉平均埃克曼下降流。为了区分这种效应与涡流补偿，建议将涡流对欧拉平均下降流的抑制称为“涡流抵消”。
AbstractThe presence of large-scale Ekman pumping associated with the climatological wind stress curl is the textbook explanation for low biological activity in the subtropical gyres. Using an idealized, eddy-resolving model, it is shown that Eulerian-mean Ekman pumping may be opposed by an eddy-driven circulation, analogous to the way in which the atmospheric Ferrel cell and the Southern Ocean Deacon cell are opposed by eddy-driven circulations. Lagrangian particle tracking, potential vorticity fluxes, and depth–density streamfunctions are used to show that, in the model, the rectified effect of eddies acts to largely cancel the Eulerian-mean Ekman downwelling. To distinguish this effect from eddy compensation, it is proposed that the suppression of Eulerian-mean downwelling by eddies be called “eddy cancellation.”