安徽省近49年短历时强降水事件趋势变化特征

为了加强对小时时间尺度的雨强特征及变化分析研究，基于安徽省1961～2009年16个台站1小时降水量资料，针对超过98%分位点的短历时强降水事件，分析其短历时强降水量、降水次数、降水强度、占总降水的比重及日分布的趋势变化特征。结果表明：近49 a来安徽省短历时强降水量总体呈增多趋势，且自东向西增加趋势逐渐显著。由M K突变检验法分析可知，2001年后有明显的向上突变整体增多，2005年后突变显著。主要是短历时强降水次数的增多导致短历时强降水量增多。近49 a来安徽省总降水量增加的78%来源于短历时强降水，且在总降水时间日趋减少的情况下，短历时强降水时间增加，对总降水的贡献越来越大。而在日分布方面，短历时强降水的日分布呈明显的双峰结构，频发时间段分别位于午后到傍晚、后半夜到早晨。但出现在上午的短历时强降水量及次数的增长趋势要明显超过午后到傍晚，因此可推测未来峰值和谷值的差异将减小，双峰的特征将逐渐减弱

TREND VARIATION OF ANHUI SHORT-TERM HEAVY RAINFALL EVENTS IN RECENT 49 YEARS

To further analyze the rain intensity characteristic and trend of the hour-scale precipitation,we focus on the short-term heavy precipitation events exceeding 98% fractile.Based on the one-hour precipitation data of Anhui 16 meteorological stations from 1961 to 2009,several characteristics of short-term heavy precipitation events were analyzed in this paper,including the short-term heavy precipitation amount,frequency,intensity,the proportion of total precipitation and the trend of daily distribution.The results showed that there was an overall increasing trend of short-term heavy precipitation in Anhui in recent 49 years,and the increasing trend was more significant in west than in east.The M-K mutation test indicated that there was an upward mutation of short-term heavy precipitation in 2001 and even more significant mutation after 2005,which were mainly caused by the increasing frequency of short-term heavy precipitation.In recent 49 years,78% of the Anhui total precipitation increase was derived from short-term heavy precipitation.Furthermore,the duration of short-term heavy precipitation had increasing trend,but there was opposite trend in the duration of total precipitation.Consequently,the contribution of short-term heavy precipitation grew greater to the total precipitation.Meanwhile,the daily distribution of short-term heavy precipitation exhibited a significant bimodal structure,performing the peak during the after midnight-morning and afternoon-dusk period.The increasing trend of the short-term heavy precipitation amount and frequency was more significant in the morning than that in the afternoon-evening.Therefore,it could be speculated that the differences of peak and trough value would be reduced,with the characteristics of Twin Peaks gradually weaken in the future.