增暖背景下华北平原极端降水事件时空变化特征

利用1961-2010年华北平原53个气象站的逐日降水资料,采用百分位值法定义极端降水事件的阈值,统计极端降水事件的降水量、频次和强度,重点分析华北平原近50 a极端降水事件时空变化特征.结果表明:(1)在气候暖化背景下,近50 a华北平原极端降水事件整体呈现下降趋势；(2)在空间格局上,极端总降水量、发生频率和强度空间格局具有一致性；(3)华北平原极端降水呈现下降趋势的区域主要分布于河北省及山东省东南沿海一带,而河南省大部呈上升趋势；(4)从时间上看各指标均呈波动变化,20世纪60年代表现出明显的减少趋势,且90年代中后期波动变化剧烈,并开始呈现上升趋势.除极端降水强度外,极端总降水量及频次均发生了突变,时间在1965年左右.

Temporal and Spatial Characteristics of Extreme Precipitation Events in North China Plain on Background of Climate Warming

Based on daily precipitation data of 53meteorological stations over the North China Plain during 1961-2010,the extreme precipitation thresholds were determined for different stations by centesimal value method.Then,the three indices of annual amount,frequency and intensity of extreme precipitation events were counted and their spatial characteristics and temporary trends were analyzed.Results showed that most stations in the North China Plain had no significant monotonic trend by each selected index of extreme precipitation events and however,the annual amount,frequency and intensity tended to reduce.Furthermore,the variation trends of extreme precipitation events exhibited similar spatial variability.Specifically,there was a positive trend of extreme precipitation events in Hebei Province and the southeast coast of Shandong Province,while a negative trend,in He'nan Province.Each index fluctuated during 1961-2010,and basically showed a significantly decreasing trend in the 1960s.The annual amount and frequency showed abrupt changes around the year of 1965.However,the intensity did not show an abrupt change.