滹沱河上游流域径流变化归因分析

以滹沱河上游流域为研究对象，采用4种基于Budyko假设的弹性系数法和SWAT模型，量化气候变化和人类活动对径流变化的贡献率．结果表明:1961—2016年，滹沱河上游流域年降水、年径流分别呈下降、显著下降趋势，而潜在蒸散发呈显著上升趋势，流域的干旱化趋势明显．基于弹性系数法的计算结果显示，气候变化对径流减少的贡献率为49.62%~61.67%，人类活动的贡献率则为38.33%~50.38%．而SWAT模拟结果却表明:气候变化的贡献率高达84.42%，而人类活动贡献率仅为15.58%．这种差异性主要源于Budyko方程中的下垫面参数反映的不仅是人类活动，还包括气候变化的影响．因此，气候变化是滹沱河上游径流减少的主要因素，但人类活动对径流的影响正日益增强．使得滹沱河上游径流减少的具体人类活动并非是土地利用类型的改变，而是经济、人口的增长所导致的水资源的过度开发利用． 

Attribution analysis of runoff variations in the upper reaches of Hutuo River Basin

The upper reaches of the Hutuo River basin was selected to study the driving forces of runoff evolution for sustainable utilization of water resources under changing environment. Quantitative analysis of the contribution rates of climate change and human activities to runoff change was presented, using 4 elasticity methods based on Budyko framework and SWAT model. Annual precipitation, annual runoff in the upper reaches of Hutuo River from 1961 to 2016 showed downward trend and significant downward trend respectively, while evapotranspiration showed significant upward trend, drought trend of the basin was marked. Elasticity-based methods showed that climate change accounted for 49.62%-61.67% of total decrease in runoff, human activities accounted for 38.33%-50.38%. SWAT simulation showed that climate change accounted for 84.42%, human activities accounted for 15.58%. Such differences emerged because landscape parameter in Budyko equations reflects not only human activities, but also impact of climate change. Therefore climate change played a dominant role in the decline in runoff in the upper reaches of Hutuo River basin, but impact of human activities on runoff is increasing. The specific reason for decrease in runoff caused by human activities was not land use change, but rather excessive development and utilization of water resources due to economic and population growth.