A New Precipitation Index for the Spatiotemporal Distribution of Drought and Flooding in the Reaches of the Yangtze and Huaihe Rivers and Related Characteristics of Atmospheric Circulation  

作　　者：宗海锋 张庆云 

机构地区：[1]Institute of Atmospheric Physics, Chinese Academy of Sciences [2]State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, Chinese Academy of Sciences

出　　处：《Advances in Atmospheric Sciences》2011年第2期375-386,共12页大气科学进展（英文版）

基　　金：supported by the projectof the National Basic Research Program of China (GrantNo. 2009CB421401);the Key Technologies R&D Program (Grant No. 2009BAC51B02);the Special Scientific Research Fund of the Meteorological Public Welfare Profession of China (Grant No. GYHY200906018);the National Natural Science Foundation of China (Grant No.40705039);the Knowledge Innovation Program of the Chinese Academy of Sciences (Grant No. IAP07415)

摘　　要：Characteristics of the spatiotemporal distributions of precipitation anomalies in the reaches of the Yangtze River and Huaihe River （YHR） were studied using EOF method. Four main precipitation pat-terns for the YHR in summer identified by the first two modes： a region-wide flood over the entire YHR （RWF）; a region-wide drought over the entire YHR （RWD）; a flood in the south with a drought in the northern region of the Yangtze River （FS-DN）; and a drought in the south with a flood in the northern region of the Yangtze River （DS-FN）. Based on the first two modes and the actual precipitation departure percentage, a new precipitation index is defined in this paper. The typical flood/drought years associated with the various rainfall patterns defined by this precipitation index are more representative and closer to reality compared to some existing precipitation indexes which just use the area-mean precipitation or the EOF time components individually. The characteristics of atmospheric circulation in summer corresponding to the four main precipitation patterns over the YHR in summer show the features of atmospheric circulation differ in different precipitation pattern years. Although the different patterns share a common main influential circulation system, such as the blocking high over northeastern Asia, the low trough of westerly flows in the mid latitudes, the West Pacific Subtropical High （WPSH）, and the high ridge over the Tibet Plateau, the difference in location and intensity of these systems can lead to different distributions of precipitation anomalies.Characteristics of the spatiotemporal distributions of precipitation anomalies in the reaches of the Yangtze River and Huaihe River （YHR） were studied using EOF method. Four main precipitation pat-terns for the YHR in summer identified by the first two modes： a region-wide flood over the entire YHR （RWF）; a region-wide drought over the entire YHR （RWD）; a flood in the south with a drought in the northern region of the Yangtze River （FS-DN）; and a drought in the south with a flood in the northern region of the Yangtze River （DS-FN）. Based on the first two modes and the actual precipitation departure percentage, a new precipitation index is defined in this paper. The typical flood/drought years associated with the various rainfall patterns defined by this precipitation index are more representative and closer to reality compared to some existing precipitation indexes which just use the area-mean precipitation or the EOF time components individually. The characteristics of atmospheric circulation in summer corresponding to the four main precipitation patterns over the YHR in summer show the features of atmospheric circulation differ in different precipitation pattern years. Although the different patterns share a common main influential circulation system, such as the blocking high over northeastern Asia, the low trough of westerly flows in the mid latitudes, the West Pacific Subtropical High （WPSH）, and the high ridge over the Tibet Plateau, the difference in location and intensity of these systems can lead to different distributions of precipitation anomalies.

关 键 词：reaches of Yangtze River and Huaihe River precipitation index precipitation patterns 

分 类 号：P467[天文地球—大气科学及气象学]