基于支持向量机的葫芦河流域径流变化的多因素贡献率分析

Analysis of the Contribution Rates of Factors to Runoff in Hulu River Based on Support Vector Machine Regression

为了定量研究气候变化及人类活动对流域径流量变化的影响,以渭河上游葫芦河流域为研究区域,利用1965—2015年降水和径流资料,采用累积距平法、双累积曲线法、支持向量机回归方法,定量分析了降水和人类活动对葫芦河流域径流量的贡献率。结果表明:与传统回归方法进行比较,支持向量机回归模型的判定系数较好,故采用向量机回归模型建立了回归方程。分析了在不考虑蒸散发的影响条件下,以1965—1971年为基准期,研究期1972—1985年、1986—1991年、1992—2015年内人类活动对径流的贡献率分别为80.44%,76.12%,86.98%。最后建立了流域水土保持措施和径流的关系,揭示了退耕还林工程措施是影响该流域径流减少的主要人类活动方式。通过本研究可为该流域水资源合理开发提供参考依据,也为未来时期水土保持工程提供优化方案。

In order to quantitatively study the effects of climate change and human activities on runoff changes in a watershed,the Hulu River Basin is selected as study area.The impacts of precipitation and human activities on the decreasing trend of runoff has been quantitatively analyzed by using accumulative anomaly,the double-accumulation curve method and support vector machine(SVM)regression methods based on the data from 1965 to 2015.The results show that SVM regression model is better than general linear regression model by comparing the coefficients of determination,thus this method is used to establish regression equation;without regard to the effect of evapotranspiration,the contributions of human activities were 80.44%,76.12%and 86.98%,respectively,at the study periods of 1972—1985,1986—1991 and 1992—2015 on the reference period of 1965—1971;the relationship between soil and water conservation measures and runoff in the watershed is established,and the project of returning farmland to forestland is identified as the main mode of human activity affecting runoff in this basin.This research can provide the guidance for the development of water resources in the basin and an optimization plan for soil and water conservation projects in the future.