Two‐dimensional indices of atmospheric blocking and their statistical relationship with winter climate patterns in the Euro‐Atlantic region
Two‐dimensional indices of atmospheric blocking and their statistical relationship with winter climate patterns in the Euro‐Atlantic region
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DOI：
10.1002/joc.1250
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发表时间：
2006-02
期刊：
影响因子：
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通讯作者：
S. Scherrer;M. Croci‐Maspoli;C. Schwierz;C. Appenzeller
中科院分区：
文献类型：
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作者：
S. Scherrer;M. Croci‐Maspoli;C. Schwierz;C. Appenzeller
利用3个新的二维阻塞指标，研究了冬季欧洲-大西洋地区对流层中层气流的主要气候型与大气阻塞之间的统计关系。重点讨论了500百帕位势变率的主要气候类型，即北大西洋涛动(NAO)。结果表明，阻塞和NAO的关系并不局限于北大西洋地区，那里的阻塞和NAO是不同位相的。所有这三个指标都表明，正NAO阶段的特征是欧洲大陆上阻塞型高压系统的增加。NAO阻塞关系从西向东的符号变化可以很好地被二维阻塞指示器探测到，而且它比传统研究的60°N附近的阻塞纬度更靠南。用季节NAO指数分析阻塞事件得到了与每日NAO指数层结相似(尽管不太显著)的结果。这表明NAO和阻塞之间的关系对所选择的时间分辨率相当不敏感。
The statistical relationship between the leading climate patterns of mid‐tropospheric flow and atmospheric blocking over the Euro–Atlantic region during winter is investigated using three new two‐dimensional blocking indicators. The focus is on the leading climate pattern of the 500‐hPa geopotential variability, i.e. the North Atlantic Oscillation (NAO). The results indicate that the blocking‐NAO relation is not restricted to the North Atlantic region, where blocking and the NAO are known to be out of phase. All three indicators show that the positive NAO phase is characterised by an enhanced occurrence of blocking‐type high‐pressure systems over the European mainland. The sign change of the NAO‐blocking relation from west to east is well detectable with the two‐dimensional blocking indicators and it is found further south than at the traditionally studied blocking latitudes near 60°N. The analysis of blocking events by seasonal NAO indices leads to similar (albeit less significant) results as with a daily NAO index stratification. This indicates that the relation between the NAO and blocking is fairly insensitive to the chosen time resolution.