北京市极端降水变化特征分析

Analysis on the Characteristics of Extreme Precipitation Change in Beijing

摘要: 利用北京1960~2014年日降水资料分析了北京地区极端降水时空变化特征。研究发现：各极端降水指数均呈下降趋势(CDD除外)，表明北京降水有所减少、强度有所减弱；极端降水量在1990s有一显著突变点，日最大降水量(Rx1day)和5日最大降水量(Rx5day)在21世纪初有一显著突变点，其它指数无明显突变；极端降水日数(R25mm)与降水强度(SDII)具有相似的空间分布，表现为北京东北部至西北部值逐渐减小；R25mm与SDII大值区在城区出现概率较大，表明城区面临的灾害风险较高；北京各极端降水指数变化率空间分布表现出明显的差异性；各极端降水指数主要是由大中小三个不同尺度的周期相互嵌套。

Abstract: Based on the daily precipitation data from 1960 to 2014 in Beijing, the temporal and spatial varia-tion characteristics of extreme precipitation in Beijing were analyzed. The study found that all ex-treme precipitation indices showed a downward trend (except CDD), indicating that Beijing’s pre-cipitation decreased and its intensity decreased; extreme precipitation had a significant mutation point in 1990s, daily maximum precipitation (Rx1day) and maximum precipitation on the 5th. The amount (Rx5day) has a significant mutation point at the beginning of the 21st century, and the other indexes have no obvious mutations; the extreme precipitation days (R25mm) and the pre-cipitation intensity (SDII) have similar spatial distribution, showing that the value from northeast to northwest of Beijing is gradually decreasing; the probability of R25mm and SDII large value ar-eas appearing in urban areas is large, indicating that the disaster risk faced by urban areas is high; the spatial distribution of the extreme precipitation index changes in Beijing shows obvious dif-ferences; the extreme precipitation indexes are mainly composed of three different large, medium and small. The periods of scale are nested with each other.