Meridional coherence of the North Atlantic meridional overturning circulation
Meridional coherence of the North Atlantic meridional overturning circulation
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DOI：
10.1029/2007gl031731
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发表时间：
2007-12-04
影响因子：
5.2
通讯作者：
Williams, Richard G.
中科院分区：
文献类型：
--
作者：
Bingham, Rory J.;Hughes, Chris W.;Williams, Richard G.
北大西洋经向翻转环流（MOC）与高纬度地区的深水形成以及对气候有重要影响的海洋 - 大气热通量有关，因此目前人们付出了巨大努力来监测MOC。虽然预计在足够长的时间尺度上，MOC的变化在深水形成区域以南的各个纬度上是连贯的，但在较短的时间尺度上是否应该具有连贯性还不清楚。在本文中，我们研究了一系列海洋模型中MOC变化的连贯性。我们发现，在一系列模型物理、分辨率和强迫情景中，大约北纬40度以北和以南的翻转特征存在变化。在北纬40度以北，变化具有强烈的年代际成分，而在其以南则以更高频率为主。这极大地降低了MOC的经向连贯性，即使在年际时间尺度上也是如此。我们从一种潜在的经向连贯模式的角度给出了物理解释，这种模式在高纬度地区最强，但在北纬40度以南被更高频率、更局部化的过程所掩盖。引用：宾厄姆，R.J.；休斯，C.W.；鲁塞诺夫，V.；威廉姆斯，R.G.（2007年），北大西洋经向翻转环流的经向连贯性。
The North Atlantic Meridional Overturning Circulation (MOC) is associated with deep water formation at high latitudes, and climatically-important ocean-atmosphere heat fluxes, hence the current substantial effort to monitor the MOC. While it is expected that, on sufficiently long time scales, variations in the MOC would be coherent across latitudes south of the deep water formation region, it is not clear whether coherence should be expected at shorter timescales. In this paper, we investigate the coherence of MOC variations in a range of ocean models. We find that, across a range of model physics, resolution, and forcing scenarios, there is a change in the character of the overturning north and south of about 40 degrees N. To the north the variability has a strong decadal component, while to the south higher frequencies dominate. This acts to significantly reduce the meridional coherence of the MOC, even on interannual timescales. A physical interpretation in terms of an underlying meridionally coherent mode, strongest at high latitudes, but swamped by higher frequency, more localised processes south of 40 degrees N is provided. Citation: Bingham, R. J., C. W. Hughes, V. Roussenov, and R. G. Williams ( 2007), Meridional coherence of the North Atlantic meridional overturning circulation.