淮河流域极端降水特征及不同重现期降水量估计

基于淮河流域25个气象站的逐日降水量资料,分析了极端日降水量、极端最大过程降水量和最大持续降水日数3个极端降水指标的时空变化特征,利用广义极值理论估算了重现期降水量.结果表明:在空间上,半湿润气候区有更强极端降水过程,而湿润气候区降水极端性偏小;在时间上,降水偏多的年代,极端降水量和极端降水过程更多,降水偏少的年代,极端降水指标数值偏小;重现期时间尺度存在临界点,在临界点以下,各站重现期降水量都会明显增大,超过临界点,淮河流域上游和南部重现期降水量变化很小,而中游、下游和北部重现期降水量增大明显.

Analysis of characteristics of extreme rainfall and estimate of rainfall during return periods in Huaihe Basin

Based on the daily rainfall data at 25 meteorological stations in the Huaihe Basin,the characteristics of spatial and temporal variation in three extreme rainfall indices,including the extreme daily rainfall,extremely persistent rainfall,and extremely persistent rainfall dates,were investigated,and the rainfall during the return periods was estimated by generalized extreme-value distribution(GEV).The results show that in spatial variation,the extreme rainfall indices were higher in the semi-humid region and lower in the humid region of the Huaihe Basin,and that in temporal variation,the extreme rainfall indices were higher in flood periods and lower in dry periods.There existed a critical point in the temporal scale of the return period: below this critical point,the rainfall increased rapidly,and when exceeding the critical point,the rainfall changed insignificantly during the return periods in the upper reaches and south of the Huaihe River and increased significantly in the middle reaches,lower reaches,and north of the Huaihe River.