A stratospheric influence on the winter NAO and North Atlantic surface climate
A stratospheric influence on the winter NAO and North Atlantic surface climate
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DOI：
10.1029/2005gl023226
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发表时间：
2005-09
影响因子：
5.2
通讯作者：
Adam A. Scaife;J. Knight;G. Vallis;C. Folland
中科院分区：
文献类型：
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作者：
Adam A. Scaife;J. Knight;G. Vallis;C. Folland
北大西洋涛动（NAO）对大西洋盆地冬季气候变率有着深远的影响。近几十年来，NAO的加强已经以远远超过全球平均变暖的速度改变了这些地区的地表气候。然而，即使有规定的气候强迫和历史海面条件，在20世纪的气候模拟中，只有微弱的NAO趋势被再现。在这里，我们表明，无法解释的加强NAO可以完全模拟在一个气候模式中，在平流层下部观测到的趋势。这意味着平流层的变化需要在模型中重现，以充分模拟北大西洋部分的地面气候变化。尽管对全球平均变暖的影响不大，我们发现，观测到的平流层环流变化的地面向下耦合可以解释1965年至1995年期间欧洲和北美地区地面气候变化的大部分。
The North Atlantic Oscillation (NAO) has a profound effect on winter climate variability around the Atlantic basin. Strengthening of the NAO in recent decades has altered surface climate in these regions at a rate far in excess of global mean warming. However, only weak NAO trends are reproduced in climate simulations of the 20th Century, even with prescribed climate forcings and historical sea‐surface conditions. Here we show that the unexplained strengthening of the NAO can be fully simulated in a climate model by imposing observed trends in the lower stratosphere. This implies that stratospheric variability needs to be reproduced in models to fully simulate surface climate variations in the North Atlantic sector. Despite having little effect on global mean warming, we show that downward coupling of observed stratospheric circulation changes to the surface can account for the majority of change in regional surface climate over Europe and North America between 1965 and 1995.