Temporal and Spatial Characteristics of Summer Rainfall in Northeast China
Han Yanfeng 1,2 Jiang Zhihong 1 Wang Ji 2 Zhang Yanmei 3 (1 Nanjing University of Information Science and Technology, Nanjing 210044; 2 Anshan Weather Bureau,Anshan 114004; 3 Liupanshui Weather Bureau,Liupanshui 553000)
Summer precipitation data in Northeast China from 1960 to 2000 was used to study the temporal and spatial features of summer rainfall. The results show that summer rainfall in Northeast China exhibited a downward trend with variation periods of 14 years and 2 to 4 years. Two abrupt summer rainfall changes occurred in 1964 and 1988/1989. The variations of summer precipitation in Northeast China can be divided into 5 types: southwest, southeast, northeast, northwest, and central Northeast China. Difference variation tendencies were found in different areas. Rainfall significantly decreased in the southeast of Northeast China and increased in the southwest of Northeast China. Meanwhile, the precipitation over different areas exhibited different periods and different occurring time of abrupt change. There is a 16-18 year cycle period in rainfall variation in the northeast of Northeast China and a 10-14 year period over the others areas. The abrupt changes took place in the 1960's and 1980's.