基于洛伦兹曲线的图们江干流区间径流分布不均匀性分析

Analysis on Temporal Inhomogenenity of Runoff in Tumen River Mainstream Based on Lorenz Curve

[目的]为水土流失、旱涝灾害等的成因分析提供科学依据。[方法]采用构建的基尼系数径流分布不均匀性模型,对图们江干流区间南坪、开山屯、河东及圈河站1959—2011年的(年)径流量、(月径流年内分配)基尼系数和(月径流年内分配)洛伦兹不对称系数的系列进行统计分析,应用Mann—Kendall方法进行趋势分析与检验。[结果]4个水文站的年径流量均呈下降趋势。南坪和开山屯站的基尼系数呈上升趋势,河东和圈河站呈下降趋势;4个水文站点的(月径流年内分配)洛伦兹不对称系数均呈上升趋势。4个水文站在1961,1965和1979年洛伦兹不对称系数均波动较大且大于1。这主要由径流量大的月份引起的,另外,同期也是历史上水旱灾害发生的年份。[结论]洛伦兹曲线可以以一种新视角量化评价径流分配的时间不均匀性及其成因。

[Objective] To provide a scientific basis for analyzing the causes of soil erosion, droughts and floods. [Methods] After building the Gini coefficient runoff uneven distribution model, annual runoff, Gini coefficient and Lorenz asymmetry coefficient（annual distribution of monthly runoff） in four hydrometric stations（Nanping, Kaishantun, Hedong and Quanhe） from 1959 to 2011 were statistically analyzed. Mann-- Kendall method was employed to do trend analysis and test in annual runoff. [Results] The annual runoffs in the four hydrometric stations showed a decreasing trend during the past years. The Gini coefficient in Nan- ping and Kaishantun showed an increase tendency, while it showed a decrease trend in Hedong and Quanhe station. The Lorenz asymmetry coefficient in the four hydrological stations showed an upward trend, and the values were greater than 1 for the four stations in 1961, 1965 and 1979, which was mainly caused by the months with large runoff volume, it is also period when drought and flood happened in history. [Conclusion] The Lorenz curve can be used to quantify and evaluate the temporal variation of runoff and its influential factor in a new perspective.