Decadal predictability of North Atlantic blocking and the NAO
Decadal predictability of North Atlantic blocking and the NAO
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DOI：
10.1038/s41612-020-0120-6
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发表时间：
2020-06-03
影响因子：
9
通讯作者：
Tibaldi, Stefano
中科院分区：
文献类型：
--
作者：
Athanasiadis, Panos J.;Yeager, Stephen;Tibaldi, Stefano
北大西洋大气阻塞和中纬度环流系统频率的多年变化能被巧妙地预测吗？季节预报方面的最新进展表明，中纬度气候变率确实具有很强的可预测性。然而，大气的可预测性一般被认为是相当有限的多年的时间尺度。NCAR的新的年代际预测实验显示出显着的技能，在复制所观察到的多年变化的冬季阻塞频率在北大西洋和北大西洋涛动（NAO）本身。这在一定程度上是由于大的合奏大小，使大气变率的可预测的组成部分，从背景的混沌组成部分出现。可预测的大气异常代表了对海洋低频变率的强迫响应，这种变化与大西洋多年代际变率（AMV）非常相似，由于现实的海洋初始化和海洋动力学，这种变化在十年后报中正确再现。欧洲-大西洋区域某些地区阻塞的发生决定了同向环流状况和北大西洋涛动等已知遥相关的相位，从而影响到风暴路径以及极端天气事件的频率和强度。因此，巧妙地预测阻塞频率和NAO的年代际波动可以用于统计预测近期气候异常，它提供了一个强有力的指示，影响气候异常也可以预测与改进的动力学模式。
Can multi-annual variations in the frequency of North Atlantic atmospheric blocking and mid-latitude circulation regimes be skilfully predicted? Recent advances in seasonal forecasting have shown that mid-latitude climate variability does exhibit significant predictability. However, atmospheric predictability has generally been found to be quite limited on multi-annual timescales. New decadal prediction experiments from NCAR are found to exhibit remarkable skill in reproducing the observed multi-annual variations of wintertime blocking frequency over the North Atlantic and of the North Atlantic Oscillation (NAO) itself. This is partly due to the large ensemble size that allows the predictable component of the atmospheric variability to emerge from the background chaotic component. The predictable atmospheric anomalies represent a forced response to oceanic low-frequency variability that strongly resembles the Atlantic Multi-decadal Variability (AMV), correctly reproduced in the decadal hindcasts thanks to realistic ocean initialization and ocean dynamics. The occurrence of blocking in certain areas of the Euro-Atlantic domain determines the concurrent circulation regime and the phase of known teleconnections, such as the NAO, consequently affecting the stormtrack and the frequency and intensity of extreme weather events. Therefore, skilfully predicting the decadal fluctuations of blocking frequency and the NAO may be used in statistical predictions of near-term climate anomalies, and it provides a strong indication that impactful climate anomalies may also be predictable with improved dynamical models.