The Effect of Northern Hemisphere Winds on the Meridional Overturning Circulation and Stratification
The Effect of Northern Hemisphere Winds on the Meridional Overturning Circulation and Stratification
复制标题
北半球风对经向翻转环流和层结的影响
DOI：
10.1175/jpo-d-18-0085.1
复制
发表时间：
2018
影响因子：
3.5
通讯作者：
Cessi, Paola
中科院分区：
文献类型：
--
作者：
Cessi, Paola
目前的范例为南半球翻转单元和相关的中层分层是，在南大洋的副极地地区的风应力驱动向北Ekman流，其中，连同全球diapycnal混合的中层沃茨的下边界，饲料的上分支的半球间翻转。由此产生的质量输送继续到北大西洋的北方半球，在那里下沉，最终返回到南大洋深处。看起来，大西洋盆地的风应力并不起作用。这种不对称性的发生是因为在大西洋的埃克曼运输被假定为返回地转在深度比半球间翻转所占据的浅得多。然而，这种垂直分离在北大西洋副极地环流区失败。使用一个概念模式和海洋环流模式在一个理想化的几何形状，我们表明，西风应力在大西洋的北方的一部分提供了两个相反的效果。在机械上，返回的Ekman运输在北大西洋反对在这一地区的下沉，减少总的翻转和加深中层分层;在机械上，副极地环流平流盐极向，促进北方半球下沉。根据哪种机制占主导地位，北方半球西风的增加可以减少或增加翻转。
The current paradigm for the meridional overturning cell and the associated middepth stratification is that the wind stress in the subpolar region of the Southern Ocean drives a northward Ekman flow, which, together with the global diapycnal mixing across the lower boundary of the middepth waters, feeds the upper branch of the interhemispheric overturning. The resulting mass transport proceeds to the Northern Hemisphere of the North Atlantic, where it sinks, to be eventually returned to the Southern Ocean at depth. Seemingly, the wind stress in the Atlantic basin plays no role. This asymmetry occurs because the Ekman transport in the Atlantic Ocean is assumed to return geostrophically at depths much shallower than those occupied by the interhemispheric overturning. However, this vertical separation fails in the North Atlantic subpolar gyre region. Using a conceptual model and an ocean general circulation model in an idealized geometry, we show that the westerly wind stress in the northern part of the Atlantic provides two opposing effects. Mechanically, the return of the Ekman transport in the North Atlantic opposes sinking in this region, reducing the total overturning and deepening the middepth stratification; thermodynamically, the subpolar gyre advects salt poleward, promoting Northern Hemisphere sinking. Depending on which mechanism prevails, increased westerly winds in the Northern Hemisphere can reduce or augment the overturning.
登录
查看更多内容
理想化的大西洋-南大洋几何形状中盆地范围内的经向翻转对底密扩散和远程风力强迫的敏感性
DOI：
--
发表时间：
2003
期刊：
影响因子：
--
作者：
Barry A. Klinger;S. Drijfhout;J. Marotzke;Jeffery R. Scott
通讯作者：
Jeffery R. Scott
影响因子：
3.2
作者：
R. Ferrari;S. Griffies;A. Nurser;G. Vallis
通讯作者：
G. Vallis
影响因子：
3.7
作者：
A. T. Parsons
通讯作者：
A. T. Parsons
半球间经向翻转环流及相关分层理论
影响因子：
3.5
作者：
M. Nikurashin;G. Vallis
通讯作者：
G. Vallis
大小很重要：大西洋比太平洋更咸的另一个原因
影响因子：
3.5
作者：
Jones, C. S.;Cessi, Paola
通讯作者：
Cessi, Paola