近50年来淮河流域极端降水的时空变化及统计特征

The Trend Analysis and Statistical Distribution of Extreme Rainfall Events in the Huaihe River Basin in the Past 50 Years

以淮河流域27个气象站点1960-2009年逐日降水观测资料为基础,选取年最大降水量序列(AM)和超门限峰值序列(POT),分析淮河流域年极端降水事件的时空变化趋势,研究淮河流域降水极值的统计特征。研究发现:过去50年,淮河流域大多数站点年最大日降水量有增加的趋势,少数站点有减少的趋势,但增加和减少的趋势均不明显。从单个气象站点50年降水序列来看,年最大日降水事件发生的时间大多集中于20世纪60-70年代,且以汛期居多。利用L-矩法、K-S检验等方法,发现GEV和GP分布分别能够较好的拟合AM和POT序列。通过计算比较在不同重现期水平下的降水量,发现POT序列及其对应的GP分布能够更好的模拟淮河流域极端降水序列。

Based on the daily precipitation data from 27 meteorological stations in the Huaihe river basin during 1960-2009,we analyzed the trend and statistical distribution of extreme precipitation events in this area.The annual maximum series（AM） and peak over threshold series（POT） are selected to describe the extreme distribution.The results show that positive trend of annual maximum precipitation is detected in most of the stations,only a small number of stations are found to be negative during the past five decades,and neither of the positive or negative trend is significant.The daily maximum precipitation events during a year almost occurred in the flood seasons of the 1960s-1970s.By the L-moments method,the parameters of three extreme distributions,which are GEV,GP and Gamma,are estimated.From the results of goodness of fit test and K-S test,we found that AM series can be better fitted by GEV model and POT series can be better fitted by GP model.In comparison with the precipitation amounts at different return levels,we found that the values obtained from POT series is slightly larger than the values from AM series,and they can better fit the observed values in the Huaihe River Basin.