干旱地区农业研究2012，Vol.30Issue(4)：172-177,6.
基于洛伦茨曲线的陕北黄土高原降雨分布不均匀性分析
Study on temporal inequality of precipitation in the loess plateau based on Lorenz curve
摘要
Abstract
Based on the model of precipitation distribution describing with Cini coefficient in Yan'an and Yulin, the annual precipitation. Gini coefficient and Lorenz asymmetry coefficient were analysized for the period of 1961-2010 and the Mann-Kendall test was employed to detect the upward or downward trend in precipitation, Gini coefficient and Lorenz asymmetry coefficient during the study period. Hie results showed that the annual precipitation in Yan an and Yulin located in the loess plateau was in a decreasing trend during the past 50 years and mean Gini coefficient was respectively 0.56 and 0.61. The yearly Lorenz asymmetry coefficient ( S > 1) accounted for a high percentage, 33.3 % in Yulin and 16.7% in Yan'an. Yulin showed increasing Gini coefficient and decreasing Lorenz asymmetry coefficient while Yan'an indicated decreasing Gini coefficient and increasing Lorenz asymmetry coefficient, but these trends had no significance at a > 95% confidence level. Therefore, precipitation distribution was becoming more and more uneven in Yulin since greater percentages of the yearly total precipitations in a few very unrainy months. However, the monthly precipitation within one year in Yan' an had a uniform distribution and a greater percentage of the precipitation in a few rainy months. In the three years of 1972, 1986 and 1997 in Yulin, the Lorenz asymmetry coefficient was greater than 1. It indicated that the precipitation inequality was caused by the heavy rainfall in some months of the year which was also the most abnormal year of drought. In conclusion, Lorenz curve from a novel perspective is an available way for evaluating quantitatively the temporal distribution of precipitation and analyzing its causes, which provided scientific basis for the analysis of mechanism of natural disasters like drought and soil loss.关键词
洛伦茨曲线/基尼系数/洛伦茨不对称系数/Mann-Kendall趋势检验Key words
Lorenz curve/Gini coefficient/Lorenz asymmetry coefficient/Mann- Kendall test分类
农业科技引用本文复制引用
史婉丽,杨勤科,李小芳,陈昂,何先进..基于洛伦茨曲线的陕北黄土高原降雨分布不均匀性分析[J].干旱地区农业研究,2012,30(4):172-177,6.基金项目
水利部公益性行业专项(基于GIS的黄土丘陵区年侵蚀产沙经验模型研究201201081-02) （基于GIS的黄土丘陵区年侵蚀产沙经验模型研究201201081-02）
