基于洛伦兹曲线的泾河张家山站径流及降雨分布不均匀性分析

Analysis of heterogenicity of runoff and precipitation distribution at Zhangjiashan station of Jinghe river based on Lorenz curve

基于泾河张家山站1970-2014年月径流量和月降雨量数据,引入洛伦兹曲线,计算泾河张家山站年径流量和年降雨量的基尼系数和洛伦兹不对称系数,利用Mann-Kendall方法进行趋势分析和检验。研究结果表明:1970-2014年泾河张家山站的年径流量和降雨量均呈下降趋势,且径流量下降趋势显著,降雨量趋势不明显。年径流量和年降雨量平均基尼系数分别为0.442和0.513;大于1的洛伦兹不对称系数的年份占总年份的比例分别约75%和20%。年径流量的基尼系数呈下降趋势,洛伦兹不对称系数呈上升趋势;年降雨量的基尼系数和洛伦兹不对称系数均呈上升趋势。径流分布趋于平均,径流量大的月份所占的比例增加;降雨分布不均性增强,主要由降雨量小的月份引起。

Based on monthly rainfall and runoff data from 1970 to 2014 at Zhangjiashan hydrological station of Jinghe River,the paper introduced Lorenz curve to calculate Gini coefficient and Lorenz asymmetry coefficient of runoff and precipitation by using Mann- Kendall method to carry out trend analysis and test. The results showed that annual runoff and rainfall displayed a falling trend from 1970 to 2014,but the downward trend of annual rainfall was not obvious. The average Gini coefficient of runoff and precipitation are 0. 442 and 0. 513 respectively; the annual proportion of Lorenz asymmetry coefficient of greater than 1 is about 75% and 20% respectively. The Gini coefficient of annual runoff showed decreasing trend and Lorenz asymmetry coefficient showed increasing trend,while both Gini coefficient and Lorenz asymmetry coefficient of annual precipitation appeared increasing trend. Therefore,the runoff distribution appears uniform and the percentage of month with large runoff volume increase; the uneven of precipitation distribution is strengthen because of the month of less precipitation.