线性回归分析表明北大西洋涛动 (NAO) 主要与大西洋、 欧洲及乌拉尔山地区阻塞的频率和强度的变化存在显著相关关系。在NAO负位相时期阻塞活动在大西洋地区较为频繁且强度较强, 正位相时期大西洋地区阻塞活动减少, 强度减弱, 而欧洲阻塞加强, 频率增加, 同时乌拉尔山地区的阻塞活动也显著减少。NAO正指数的增强和减弱对应于大西洋和欧洲阻塞活动的不同变化。局地阻塞活动频率分布显示： 在NAO正指数增强的阶段, 大西洋的阻塞活动受到明显抑制而欧洲大陆阻塞活动明显增加, 活动中心向欧洲大陆偏移; 但在NAO正指数减弱的阶段, 阻塞活动中心向大西洋一侧移动。区域性阻塞的逐年变化表现为： 大西洋和乌拉尔地区阻塞在NAO指数增强的阶段呈下降趋势, 欧洲阻塞呈增加的趋势; 在NAO指数减弱的阶段大西洋阻塞为弱的上升趋势, 欧洲和乌拉尔地区阻塞呈下降趋势。中纬度涡旋活动的强弱和位置对NAO位相的变化起到重要作用。大西洋风暴活动向东加强有利于NAO趋于正位相, 对应于欧洲大陆阻塞发生频率增加; 但其进一步加强可使大西洋阻塞活动增加。
The linear regression analysis shows that there is a significant correlation between the North Atlantic Oscillation (NAO) and the variation of blocking frequency and intensity in the Atlantic Ocean, Europe, and the Ural Mountains. During the negative NAO phase, the blocking activities are more frequent and stronger in the Atlantic region. In the positive NAO phase, the blocking activities in the Atlantic region and their frequency diminish, which enhance in Continental Europe, and at the same time the blocking activities reduce markedly in the Ural Mountains. The increase and decrease of positive NAO index correspond to different variations of the blocking activities in the Atlantic Ocean and Europe. The local distribution of blocking activities frequency demonstrates that during the increasing phase of the positive NAO index the blocking activities in the Atlantic Ocean are significantly restrained, which enhance evidently in Continental Europe, and their center shifts to the Continent. But in the weakening stage of the positive NAO index, the center of blocking activities shifts westward to the Atlantic Ocean. The annual changes in the regional blocking events show that the blocking situations in the Atlantic and the Urals region have a downward trend during the enhancing phase of the NAO index, which increase in Europe; in the weakening phase of the NAO index, the Atlantic blocking cases present a weak uptrend, which trend downwards in Europe and the Ural region. The strength and position of mid\|latitude eddy play an important role in the NAO phase variations. The eastward strengthening of the Atlantic storm track is beneficial to NAO tending to positive phase, corresponding to increasing in blocking frequency in Continental Europe, but further strengthening can increase blocking activities in the Atlantic Ocean.