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.

是否可以熟练地预测北大西洋大气阻塞和中纬度环流区域频率的多年变化？季节性预报的最新进展表明，中纬度气候的变化确实显示出显着的可预测性。但是，人们普遍发现，在多年的时间尺度上，大气的可预测性非常有限。发现来自NCAR的新的年代际预测实验在再现观察到的北大西洋和北大西洋涛动（NAO）本身冬季阻塞频率的多年变化方面显示出卓越的技能。这部分是由于较大的整体大小，使大气变化的可预测成分从背景混沌成分中显现出来。可预测的大气异常代表了对海洋低频变化的强迫响应，这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，在年代际后兆中正确地再现了大西洋多年代际变率。在欧洲大西洋区域的某些区域发生的阻塞，决定了同时发生的环流机制和已知遥距连接（例如NAO）的阶段，从而影响了风暴的轨迹以及极端天气事件的频率和强度。因此，熟练地预测阻塞频率和NAO的年代际波动可用于近期气候异常的统计预测，并且有力地表明，通过改进的动力学模型也可以预测有影响的气候异常。