黄河流域天然河川径流量演变归因分析

受气候变化和人类活动影响，黄河流域水资源量持续衰减。以往水资源归因分析的研究主要针对气候变化和人类活动对实测径流量衰减的贡献，对天然径流量衰减的原因关注不够，不利于支撑黄河流域水资源高效利用和科学管理。基于黄河二元水循环模型评价不同时期黄河流域天然河川径流量，并采用多因素归因分析方法分析主要影响因素对天然河川径流量衰减的贡献。结果表明，2016年水平年情景相比于1956—1979年水平年情景，花园口断面多年平均天然河川径流量减少114.6亿m3，其中气候变化、下垫面变化和社会经济取用水影响的贡献率分别为24.4%、25.0%和50.6%。从分区来看，兰州以上气候变化是主导因素，兰州以下人类活动是主导因素。为遏制天然河川径流量衰减的趋势，促进黄河流域生态保护与高质量发展，应加强深度节水、刚性控水、适度增水、强化管水和立法护水。

Attribution analysis of the natural runoff evolution in the Yellow River basin

Natural runoff in the Yellow River basin has suffered a sustained decline under the influence of climate change and human activities.Earlier studies mainly investigated the attribution of climate change and human activities,while focusing on the observed runoff decline and rarely on natural runoff,which is not conducive to the efficient utilization and scientific management of water resources in the Yellow River basin.In this study,natural runoff during different periods in the Yellow River basin were evaluated by means of a dualistic water-cycle model,while the contribution of the main factors on the declining natural runoff was elucidated by a multi-factor attribution method.Results revealed that the 1956—2016 annual natural runoff at the Huayuankou station was reduced by 11.46 billion m³ compared to 1956—1979.The contributions of climate change,land-use change,and social water use were estimated to be 24.4%,25.0%,and 50.6%,respectively.Analysis of the contributions in each Yellow River zone indicated that climate change and human activities were the dominant factors upstream and downstream of Lanzhou,respectively.In order to mitigate the declining trend of natural runoff and promote the ecological protection and high-quality development in the Yellow River basin,stronger measures,such as deep water saving,rigid water control,moderate water increase,efficient water management,and water protection legislation,should be implemented.