黄河源区下垫面变化对水文过程的影响

Impact of underlying surface changes on hydrological process in source area of Yellow River

量化评估下垫面变化对水平衡要素的影响,对揭示黄河源区径流变化归因具有重要意义。论文建立了考虑土地覆被变化(LUCC)和叶面积指数(LAI)动态变化的可变下渗容量(VIC)模型,模拟了下垫面变化条件下的降水-径流响应关系。结果表明,考虑下垫面动态变化的VIC模型能更好地模拟源区水文过程,相对误差降低8.8%~12.9%。2001—2018年LAI和LUCC综合作用导致植物蒸腾量年均增加约15%,玛曲和唐乃亥断面径流分别减少约9.19%和7.17%。LAI对径流影响较LUCC大,LAI对玛曲和唐乃亥断面多年平均径流量的贡献分别为-4.80%和4.48%,而LUCC的贡献为0.16%和-3.15%。研究解释了下垫面变化是源区降水增加条件下径流变化不显著的原因,对认识气候变化和生态保护的水文响应规律有借鉴意义。

Quantitative assessment of the impact of underlying surface changes on water balance components is of great significance for revealing the attribution of runoff changes in the source region of the Yellow River(SRYR).This study simulates the relationship between precipitation and runoff under underlying surface changes,using a variable infiltration capacity(VIC)model considering dynamic land use/cover change(LUCC)and leaf area index(LAI)change.The results show this model improves the simulations of the SRYR hydrological process through considering the dynamic evolution of the underlying surface,achieving a relative error reduction of 8.8%-12.9%.From 2001 to 2018,the combined effects of LAI and LUCC led to an average annual increase of 15% in plant transpiration,while the runoffs at Maqu and Tangnaihai were decreased by 7.17% and 9.19%,respectively.The impact of LAI on runoff was more significant than that of LUCC.The average annual contributions of LAI to these two runoffs were-4.80% and 4.48%,respectively,while those of LUCC were 0.16% and-3.15%.The study explains the changes in underlying surfaces are the cause of insignificant changes in runoff under increasing precipitation in SRYR,and deepens our understanding of the hydrological responses to climate change and ecological protection.