中国东北地区夏季旱涝的大气环流异常特征

The Unusual Characteristics of General Circulation in Drought and Waterlogging Years of Northeast China

利用东北地区均匀分布的６９个测站３５年（１９６１～１９９５年）夏季月平均降水资料和 ＮＣＥＰ／ＮＣＡＲ １９５８～１９９７年月平均再分析资料，对我国东北地区夏季旱涝发生的大气环流异常特征及其差异进行了诊断分析研究。结果表明，东北地区旱涝年夏季，高纬和极区大气环流特征、东北亚异常长波槽脊的分布和活跃程度、东亚大槽和西太平洋副热带高压的位置和强度等均有十分明显的差别。不仅如此，该区域夏季降水异常还显著地受到亚洲季风诸系统的影响，包括南亚季风，也包括南海季风和副热带季风，并且高空西风急流的位置和强度也有明显变化。涡度、散度、垂直速度和水汽含量等物理量特征在旱涝年不仅有截然相反的分布，而且还表现出与低纬地区存在着不同的联系方式。位于菲律宾以东洋面上行星尺度的高层辐散和低层辐合也有一定不同，并且受热带地区大气加热强度变化的影响，东北地区所在经度上的经圈环流在旱涝年也发生了明显变化，从而对该区域降水异常产生影响。

By using the NCEP/ NCAR reanalysis monthly mean data from 1958 to 1997 and summer precipitation from 69 observation stations of Northeast China, the general circulation anomaly characteristics in drought and waterlogging years of this area have been studied. The results show that the features of general circulation in the high-latitude and pole area, the location and the intensity of subtropical high of the western Pacific and the unusual long wave ridge and trough in Northeast Asia are quite different between drought and waterlogging years. The activities of Asia summer monsoon (including South Asia summer monsoon and Fast Asia summer monsoon) and the variations of planetary scale convergence and divergence circulation in tropical zone have the important impacts to the summer precipitation anomaly in northeast area in China.