Temporal Variations of Summer Precipitation Extremum in the Northeast China in Recent 42 Years

Daily rainfall amount of 93 weather stations from 1959 to 2000 was used to analyze the temporal change of summer rainfall extremes in the Northeast China.The result showed that the intensity of summer rainstorm increased,days reduced and the changes of rainstorm and precipitation were consistent.Extreme dry incident increased in recent 42 years,and it occurred extremely frequent since mid 1990s,which was one important reason for the occurrence of drought in Northeast China.Extreme rainy days were reducing and extreme rainy days were important factors influencing the total precipitation before mid 1990s,while precipitation intensity was important factors for the precipitation in summer after mid 1990s.The average precipitation in maximum three days showed no distinct features of interannual changes.