夏季河套地区北部极端降水事件统计分析

摘要

利用我国河套地区北部1960 ～ 2004年夏季(6～8月)20个台站逐日降水资料,用百分位阈值方法定义了不同台站的极端降水阈值,分析了河套地区北部近45年夏季极端降水的时空分布特征以及极端降水的区域性和连续性特征.结果表明,河套地区北部夏季极端降水阈值自西北向东南逐渐增大,夏季极端降水事件45年间呈弱的上升趋势,20世纪80年代以前极端降水事件存在2.5 ～3.0和8 ～ 10年的周期振荡,80年代～90年代中期以年际变化为主,河套地区北部极端降水的持续性和区域性均较低.%Based on the daily precipitation data collected in summer from 20 meteorological stations in north of Hetao during 1960 -2004, according percentile method, the extreme precipitation threshold values were defined in different stations, temporal and spatial characteristics of extreme precipitation events (EPE) , regionality and persistence were analyzed. The results showed that the extreme precipitation threshold value increased from northwest to southeast, the frequency of EPE indicated a faint increasing trend, there were periodical variations of 2.5 - 3. 0 years and 8-10 years, both the persistence and the regionality of extreme precipitation in Hetao were lower.