近42年来东北地区夏季降水极值的时间特征分析

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

利用1959～2000年东北地区93站逐日降水资料,分析了东北地区夏季降水极值的时间特征,结果发现,东北地区夏季暴雨强度增强,暴雨日数略减少,暴雨量与总雨量的变化趋势一致。极端干燥事件近42年来增加显著,特别是20世纪90年代中期以来极端干燥事件发生异常频繁,是近年来东北地区干旱频繁发生及灾情严重的一个重要原因。极端连雨日总体呈较明显的减少趋势;极端连雨日是影响20世纪90年代中期之前夏季总降水量的重要因子,而降水强度是影响90年代中期之后夏季降水总量的重要因子。最大3 d平均降水量无明显的年代际变化特征。

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.