论文部分内容阅读
以四湖流域荆门、荆州、石首、监利、潜江5个代表性气象站点1956-2007年的日降水资料为基础,分别选取Z指数法及广义帕累托分布对各气象站春、夏、秋三季的标准降水序列及降水距平序列进行拟合,分析各气象站点在不同季节内发生旱涝灾害的频率,在此基础上采用二维Clayton Copula分布函数拟合春-夏、夏-秋的降水分布,进一步计算出各站点旱涝交替事件的发生概率.结果表明:1)Z指数法比降水距平法更适于分析四湖流域的旱涝情况;2)四湖流域在春-夏、夏-秋两时段发生旱涝交替的频率平均为16.27％,其中,潜江最容易发生旱涝异常现象.春-夏与夏-秋发生旱涝交替事件频率没有明显差别.,Through the daily precipitation data of 1956-2007 at Jingmen,Jingzhou,Shishou,Jianli and Qianjiang meteorological stations in the Sihu River Basin,the sequences of the stations were fitted by Z index and GP model to estimate the probability of drought and waterlogging; Clayton Copula function was used to fit the spring-summer and summer-autumn percentage of precipitation anomalies sequences and the probability of drought and waterlogging altating were calculated.The results show that:1.The Z index performs better than GP model in the altating events of drought and waterlogging of Sihu River Basin;2.The drought and waterlogging altating events are most likely to take place in Qianjiang,and the frequency of spring-summer and summer-autumn altating events in Sihu River Basin are 16.27％,there is no difference between the spring-summer altating events of drought and waterlogging and the summerautumn’s.