黄河入海径流变化及影响因素

Analysis of the runoff variation of the Yellow River to the sea and its influencing factors

黄河入海径流是黄河水循环的重要分量,涉及整个流域,它的变化是流域气候与人类活动的综合体现。以黄河入海口利津水文站1963～2009年实测径流量年均值为基础,采用随机水文学方法,对入海径流动态变化进行了分析;结合流域内7个径流来源区的78个气象站同时段月均降水和气温数据及流域内取水量和水利工程等资料,探讨了不同径流来源区的气候因素和人类活动对入海径流量的影响。结果表明:近50年来入海实测径流量呈显著下降趋势,且存在1968年、1985年、1996年与2002年这四个突变点;入海天然径流量同样呈显著下降趋势,只有1985年一个突变点。唐乃亥以上区间的降水量、兰州至龙门区间的气温以及龙门至三门峡区间的降水和气温是引起入海天然径流量变化主要因素;气温因素的季节性变化对入海天然径流量也有影响,其中夏季降水与冬季气温是重要的因素。自20世纪70年代以来,人类活动对入海径流量的影响不断加强,且在耗水量、水土保持及水利工程等方面表现出明显的空间差异。取水量、降水、气温对黄河入海实测径流量变化的贡献率分别为42.2%、39.2%、18.6%。

The runoff of the Yellow River to the sea is an important component of water cycle, which involves the entire basin, and its temporal and spatial changes are comprehensive reflection of climate and human activities in the basin. Based on the measured runoff data （1963-2009） from the Lijin hydrographic station at the Yellow River estuary, the evolutionary characteristics of runoff into the sea in the past 50 years were analyzed using stochastic hydrology methods. Combining average monthly precipitation and temperature data obtained from 78 weather stations in seven runoff source areas and water withdrawal and water conservancy projects, we explored the influence of climate change and human activities in different runoff source areas on the runoff to the sea. The measured runoff to the sea showed a significant decreasing trend in the evolution of the past 50 years, and four hopping points were identified in the runoff sequence, and the natural runoff to the sea saw the same trend and had only one hopping point. The pre- cipitation in the region above Tangnaihai, the temperature in Lanzhou-Longmen region and the precipitation and temperature in Longmen-Sanmenxia region were a principal factor affecting the change of natural runoff to the sea. Seasonal climatic factors had also influ- ence on runoff to the sea, and summer precipitation and winter temperature were the important factors. The impact of human activities on runoff into the sea continued to increase after the 1970s. Different runoff source areas showed significant differences in water consumption, soil conservation and water conservancy projects. The contribution rates of different influencing factors to the measured runoff into the sea were different, and those of the water withdrawal, precipitation and temperature were 42.2%, 39.2%, and 18.6%, respectively.