近30年太湖流域极端降水特征分析

基于太湖流域98个代表雨量站1981~2010年逐日降水资料,利用百分位阈值法定义各测站极端降水阈值,分析了不同极端降水事件的频次及其平均强度的空间分布特征,并对极端降水进行趋势分析。结果表明,浙西区极端降水事件频次出现较高,湖西区的中部和东南部降水强度较大;从季节分布来看,汛期5~10月出现极端雨日频次高,且强度相对较大;全太湖流域各区年平均极端雨日普遍呈微弱下降趋势,武澄锡虞区、阳澄淀泖区、浦东浦西区极端降水平均强度呈上升趋势,其他区变化趋势不显著。

Characteristics Analysis of Extreme Precipitation in Taihu Lake Basin in the Last 30 Years

Based on the daily precipitation data of 98 representative stations in the Taihu Lake Basin during 1981-2010, defining the percentile as the threshold of extreme precipitation for each station, the characteristics of the spatial distribution of the frequency and the average intensity of extreme precipitation events and extreme precipitation trend are analyzed. The results show that the frequency of extreme precipitation events is higher in the Zhexi region, the average intensity is lager in the central and southeast in the Huxi region; from the seasonal distribution, it happens frequently from May to October, and the intensity is relatively larger. Trend shows that the average annual extreme precipitation days weakly decreases in the Taihu Lake Basin, the average intensity in the Wuchengxiyu region, the Yangchengdianmao region and the Pudongpuxi region appear upward trend, but there is no obvious trend in the other regions.