ANALYSIS OF THE CHARACTERISTICS OF SUSTAINED TORRENTIAL RAINS IN JUNES DURING 1958-2000

Day-to-day precipitation data of Junes during the 43 years of 1958-2000 from stations to thesouth of Yangtze River are used to divide regions and run statistical analysis of sustained torrential rainfallprocesses. A preliminary analysis is then made based on it and the results show that June is the month inwhich torrential rains in the southern half of China take place frequently and sustained torrential rainsoccur at the same time in South China and the area to the south of Yangtze River. In addition, the analysisgives the basic features of sustained torrential rains of June in China and their interannual variabilitypatterns, with the suggestion that the amount of these events increases significantly after the 1990s. Lastly,the sustained torrential rains occurring in Junes of 1994, 1998 and 2005 in the southern half of China aretaken as examples in the research on the basic patterns and formation mechanisms of the evolution ofdouble rain-bands during the rain season in South China and the area to the south of Yangtze River. Theanalysis shows that the large scale environment field in which sustained torrential rains occur is related tothe stable sustaining of the South Asia High and upper level jet streams.