20世纪后半期以来赣江流域极端降水事件分析

Analysis of Extreme Precipitation Events in Ganjiang River Basin Since the Second Half of the 20th Century

全球气候变暖的背景下,局地极端降水事件发生频率逐渐上升。选用极端降水阈值(EPT)、极端降水量(R95)、极端降水天数(RD95)、极端降水强度(RI95)、连续五日最大降水量(RX5day)和一日最大降水量(RX1day)6个极端降水指数,采用百分位阈值法、M-K趋势分析法、滑动t检验法和Kriging空间插值法对1964—2013年赣江流域的极端降水事件进行分析。结果表明:①赣江流域内大部分站点的极端降水指数呈不显著上升趋势;②各站点极端指数的突变时间大多数集中于20世纪八九十年代,且有少数站突变非常显著(α=0.01);③各极端降水指数除RD95外均呈现由东向西递减的规律,与之相反,RD95呈现出由西向东递减的变化。研究结果可为赣江流域防洪减灾和水资源的开发利用提供参考价值。

Under the background of global warming,the frequency of local extreme precipitation events increases gradually.This paper selects six extreme precipitation indexes such the extreme precipitation threshold(EPT),extreme precipitation(R95),extreme precipitation days(RD95),extreme precipitation intensity(RI95),maximum precipitation for five consecutive days(RX5day)and maximum precipitation for one day(RX1day),and analyzes the extreme precipitation events in Ganjiang River Basin from 1964 to 2013 by percentile threshold method,M-K trend analysis method,sliding t test method and Kriging spatial interpolation method.The results show that:①The extreme precipitation index of most stations in Ganjiang River Basin shows non-significant upward trend;②The mutation time of extreme precipitation index of each station is mostly concentrated in the 1980s and 1990s,and a few stations have significant mutation(α=0.01);③Except for RD95,all the extreme precipitation indexes decrease from east to west,on the contrary,RD95 decreases from west to east.The research results can provide reference for flood control,disaster reduction and water resources development and utilization in Ganjiang River Basin.