近50年伊洛河流域径流演变归因分析

流域尺度的径流变化反映了气候和人类活动的综合影响，然而目前伊洛河流域径流演变的量化归因尚不明晰。基于Budyko假设构建解析径流变化归因的模型，量化评估径流对各环境因素变化的敏感性系数，定量揭示各因素对径流变化的贡献。结果表明，1970—2018年间，伊洛河流域径流显著下降（α=0.05），且在1991年发生突变，突变后径流减少了46.43 mm（34.32%）。径流变化对降水、潜在蒸散发和下垫面参数的敏感性系数分别为0.42、?0.18和?78.36，即降水每增加1 mm将导致径流增加0.42 mm，潜在蒸散发量每增加1 mm将导致径流减少0.18 mm，下垫面参数每增加1个单位将导致径流减少78.36 mm。气候变化和人类活动对径流变化的贡献率分别为42.60%和56.36%，人类活动引起的下垫面变化是径流变化的主要原因，其中植被变化是下垫面变化的主导因素。研究结果可为流域径流演变归因和水资源管理规划提供理论支撑。

Analysis on attribution of runoff evolution in Yiluo River basin in the past 50 years

Watershed-scale runoff changes reflect the combined effects of climate and human activities. However, the attribution of runoff evolution in the Yiluo River basin is currently unclear. Based on the Budyko hypothesis, this study team builds a model to analyze the attribution of runoff changes, quantitatively evaluates the sensitivity coefficient of runoff to changes in various environmental factors, and quantitatively reveals the contribution of various factors to runoff changes. The results show that the runoff of the Yiluo River Basin decreased significantly (α=0.05) from 1970 to 2018, a mutation point occurred in 1991 and the runoff decreased by 46.43 mm (34.32%) during the change period. The sensitivity coefficients of runoff changes to precipitation, potential evapotranspiration and underlying surface parameters are 0.42, ?0.18 and ?78.36, respectively, that is, every 1 mm increase in precipitation will lead to an increase of 0.42 mm in runoff, and an increase of 1 mm in potential evapotranspiration will lead to a decrease of 0.18 mm in runoff. Each increase of 1 unit of the underlying surface parameter will result in a decrease of 78.36 mm in runoff. The contribution rates of the climate change and human activities to runoff change are 42.60% and 56.36%, respectively, and underlying surface changes caused by human activities are the main reason of runoff changes, among which vegetation change is the dominant factor in underlying surface changes. The research results can provide theoretical support for the attribution of runoff evolution and water resources management planning in the basin.