The signature of low-frequency oceanic forcing in the Atlantic Multidecadal Oscillation
The signature of low-frequency oceanic forcing in the Atlantic Multidecadal Oscillation
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DOI：
10.1002/2016gl067925
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发表时间：
2016-03-28
影响因子：
5.2
通讯作者：
Zanna, Laure
中科院分区：
文献类型：
--
作者：
O'Reilly, Christopher H.;Huber, Markus;Zanna, Laure
大西洋数十年涛动（AMO）显着影响周围大陆的气候，此前曾被归因于大西洋经向翻转环流的变化。然而，最近在没有海洋环流变化的气候模型中报告了类似的数十年变化。我们通过观测和耦合气候模型模拟分析了北大西洋中纬度地区湍流热通量与海面温度（SST）之间的关系，无论有没有海洋环流变化。在海洋环流变化的观测和模型中，与 AMO 相关的海温异常与十年时间尺度上的热通量呈正相关，而在没有海洋环流变化的模型中，当热通量异常导致时，异常与热通量呈负相关。这些关系是在一个简单的随机模型中捕获的，并且主要依赖于海表温度的低频强迫。全耦合模型能够更好地捕捉这一特征，更有效地再现观察到的 AMO 对欧洲夏季气温的影响。
The Atlantic Multidecadal Oscillation (AMO) significantly influences the climate of the surrounding continents and has previously been attributed to variations in the Atlantic Meridional Overturning Circulation. Recently, however, similar multidecadal variability was reported in climate models without ocean circulation variability. We analyze the relationship between turbulent heat fluxes and sea surface temperatures (SSTs) over the midlatitude North Atlantic in observations and coupled climate model simulations, both with and without ocean circulation variability. SST anomalies associated with the AMO are positively correlated with heat fluxes on decadal time scales in both observations and models with varying ocean circulation, whereas in models without ocean circulation variability the anomalies are negatively correlated when heat flux anomalies lead. These relationships are captured in a simple stochastic model and rely crucially on low-frequency forcing of SST. The fully coupled models that better capture this signature more effectively reproduce the observed impact of the AMO on European summertime temperatures.