Does the vorticity flux from Agulhas rings control the zonal pathway of NADW across the South Atlantic
Does the vorticity flux from Agulhas rings control the zonal pathway of NADW across the South Atlantic
复制标题
厄加勒斯环的涡量通量是否控制 NADW 穿越南大西洋的纬向路径
DOI：
10.1029/2011jc007684
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发表时间：
2012
影响因子：
--
通讯作者：
L. Beal
中科院分区：
文献类型：
--
作者：
E. Sebille;E. Sebille;W. Johns;L. Beal
[1]作为全球温盐环流的一部分，一些北大西洋深层水（NADW）从大西洋海盆流出到非洲南部。观测表明，有一条以南纬25°为中心的准纬向通道将北大西洋西北部海水向东输送，将西部深层边界流与开普盆地连接起来。然而，目前还不清楚是什么设定了这条道路。特别是，沃茨必须向南移动通过开普盆地，从而穿过行星涡度等值线，才能离开盆地。在这里，我们发现，涡厚度通量引起的Agulhas环向西北移动的力量通过好望角盆地的NADW环流。25°S的路径在保持位涡的情况下为该环流的东南向流动提供营养。在1/10°分辨率的海洋模式中，使用300年平流的拉格朗日浮标，我们表明，在我们的模式中，NADW最常见的路径位于Agulhas环走廊的正下方。通过分析模型中的速度和密度场，我们发现这些环的衰减，以及它们随深度的向前倾斜，导致在沃茨中向南的速度，穿过行星涡度等值线，为1至2厘米/秒。相关的流函数模式产生了一个从25°S的深层西边界流向非洲南端输送4 Sv NADW的深层环流。
[1] As part of the global thermohaline circulation, some North Atlantic Deep Water (NADW) exits the Atlantic basin to the south of Africa. Observations have shown that there is a quasi-zonal pathway centered at 25°S carrying NADW eastward, connecting the Deep Western Boundary Current to the Cape Basin. However, it has been unclear what sets this pathway. In particular, waters must move southward through the Cape Basin, thereby crossing isolines of planetary vorticity, in order to exit the basin. Here, we find that an eddy thickness flux induced by Agulhas rings moving northwestward forces a circulation of NADW through the Cape Basin. The pathway at 25°S feeds the southeastward flow of this circulation while conserving potential vorticity. Using Lagrangian floats advected for 300 years in a 1/10° resolution ocean model, we show that the most common pathway for NADW in our model lies directly below the Agulhas ring corridor. By analyzing the velocity and density fields in the model, we find that the decay of these rings, and their forward tilt with depth, results in a southward velocity, across isolines of planetary vorticity, of 1 to 2 cm/s in the deep waters. The associated stream function pattern yields a deep circulation transporting 4 Sv of NADW from the Deep Western Boundary Current at 25°S to the southern tip of Africa.
影响因子：
--
作者：
E. Sebille;P. Leeuwen;A. Biastoch;W. D. Ruijter
通讯作者：
E. Sebille;P. Leeuwen;A. Biastoch;W. D. Ruijter
中尺度扰动控制非洲南部的海洋间交换
影响因子：
5.2
作者：
Biastoch;J. R. E. Lutjeharms;C. W. Böning;M. Scheinert
通讯作者：
M. Scheinert