Arctic dipole anomaly and summer rainfall in Northeast China  

作　　者：WU BingYi ZHANG RenHe D'Arrigo ROSANNE 

机构地区：[1]State key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, Beijing 100081, China [2]State Key Laboratory of Cryospheric Sciences, Chinese Academy of Sciences, Lanzhou 730000, China [3]Tree-Ring Laboratory, Lamont-Doherty Earth Observatory, Palisades, NY 10964, USA

出　　处：《Chinese Science Bulletin》2008年第14期2222-2229,共8页

基　　金：Supported by the National Key Basic Research and Development Project of China (Grant No. 2004CB418300);the National Basic Research Program of China (973 Program) (Grant No. 2007CB411505);Chinese COPES project (GYHY200706005);the National Natural Science Foundation of China (Grant No. 40475030);R. D’Arrigo acknowledges support from the National Science Foundation (Grant No. OCE 04-02474);Lamont-Doherty Earth Observatory Contrib. No. 7126

摘　　要：A dipole structure anomaly in summer Arctic atmospheric variability is identified in this study, which is characterized by the second mode of empirical orthogonal function (EOF) analysis of summer monthly mean sea level pressure (SLP) north of 70°N, accounting for 12.94% of the variance. The dipole anom- aly shows a quasi-barotropic structure with opposite anomalous centers over the Canadian Arctic and the Beaufort Sea and between the Kara Sea and the Laptev Sea. The dipole anomaly reflects alternating variations in location of the polar vortex between the western and eastern Arctic regions. The positive phase of the dipole anomaly corresponds to the center of the polar vortex over the western Arctic, leading to an increase in summer mean rainfall in Northeast China. The dipole anomaly has a pre- dominant 6-year periodicity, and shows interdecadal variations in recent decades.A dipole structure anomaly in summer Arctic atmospheric variability is identified in this study, which is characterized by the second mode of empirical orthogonal function （EOF） analysis of summer monthly mean sea level pressure （SLP） north of 70°N, accounting for 12.94% of the variance. The dipole anomaly shows a quasi-barotropic structure with opposite anomalous centers over the Canadian Arctic and the Beaufort Sea and between the Kara Sea and the Laptev Sea. The dipole anomaly reflects alternating variations in location of the polar vortex between the western and eastern Arctic regions. The positive phase of the dipole anomaly corresponds to the center of the polar vortex over the western Arctic, leading to an increase in summer mean rainfall in Northeast China. The dipole anomaly has a predominant 6-year periodicity, and shows interdecadal variations in recent decades.

关 键 词：极地异常 北极 夏季 雨季 中国北方 

分 类 号：P4[天文地球—大气科学及气象学]