乌东德水电站坝区极端降水事件变化特征分析

Analysis on Variation Characteristics of Extreme Precipitation Events in Wudongde Hydropower Station Dam Area

利用乌东德水电站坝区临近的会东和禄劝气象站的逐日降水量资料,基于极端降水指数分析坝区极端降水事件的时空变化特征。结果表明:强降水和极端降水事件空间差异不显著。由CDD(连续无降水日数)和CWD(连续降水日数)两个指数分析得出乌东德水电站坝区金沙江北岸的上游区域比南岸的下游区域更易发生干旱。强降水和极端降水事件季节特征明显,主要集中在5—9月,12月至次年4月罕见强降水事件,极端降水频次峰值出现在6月和7月。CDD和CWD的线性趋势分析看出近46 a乌东德坝区更容易发生干旱,不利于发生连续洪涝。

Using the daily precipitation data of Huidong and Luquan meteorological stations near the dam area of Wudongde Hydropower Station,this paper analyzes the temporal and spatial variation characteristics of extreme precipitation events in the dam area based on the extreme precipitation index.The results show that there is no significant spatial difference between heavy precipitation and extreme precipitation events.The analysis of CDD and CWD shows that the upstream area on the North Bank of Jinsha River in Wudongde Hydropower Station dam area is more prone to drought than the downstream area on the south bank.The seasonal characteristics of heavy precipitation and extreme precipitation events are obvious,mainly concentrated in May to September,rare heavy precipitation events from December to the next April,and the peak frequency of extreme precipitation occurs in June and July.The linear trend analysis of CDD and CWD shows that Wudongde dam area is more prone to drought in recent 46 years,which is not conducive to continuous flooding.