黄河流域气候与农业种植面积变化对径流的影响

根据黄河流域1960—2005年5个水文站逐日流量、77个气象站1959—2013年逐日降水数据,结合流域内主要农作物种植面积及大型水库资料,全面探讨气候与农业面积变化及人类活动对黄河流域径流变化的影响.研究表明:黄河流域所有流量分位数总体呈下降趋势,并于1980s中后期到1990s中期发生突变.降水变化是黄河流域径流变化的主要影响因素.在考虑不同流量分位数情况下,农作物种植面积变化对不同分位数径流变化的影响也有差异性.花园口站农作物种植面积变化对径流量量级和可变性均有显著影响;其余4站各项气候变化与农作物种植指标参数较大,虽均未达到10%的显著性水平,但仍会对径流的量级变化产生影响.对唐乃亥站,农作物耕作面积的下降减少了灌溉用水,在0.5流量分位数时有高达60%增加径流量的间接作用.对于头道拐站,农作物耕作面积的增加使得流域总蒸发量增加,灌溉用水增加,在0.3流量分位数时有高达40%减少径流量的间接作用.该研究为气候变化与人类活动影响下黄河流域水资源优化配置提供重要理论依据.

Quantification impacts of climatic and agricultural changes on streamflow variations in the Yellow River Basin

Based on daily streamflow data covering a 1960-2005 period, daily precipitation data during 1959-2013 period, together with data concerning crop areas and water reservoirs, thorough investigation is done on impacts of human activities (crop areas and water reservoirs in this study) and climatic changes (precipitation changes in this study) on hydrological processes of the Yellow River Basin. Differentiation is done on fractional contribution of climatic changes and human activities to changes in streamflow. The results indicate that percentiles of streamflow components of the Yellow River Basin are all in descending tendency and abrupt changes can be observed during mid and late 1980s and mid-1990s. The results of this study support the statement that precipitation plays the critical role in changes of streamflow across the Yellow River Basin. However, agricultural irrigation reflected by changes in crop areas can have different impacts on different streamflow components defined by different percentiles. Specifically, crop area changes have evident influences on streamflow magnitude and also variability of streamflow changes at the Huayuankou Station in the lower Yellow River Basin. Changes of climatic and crop indices are subject to minor variations but have apparent effects on magnitude of streamflow. For quantiles around the median, there is up to a 60% increment in the relation between streamflow and crop areas at the Tang Naihai Station. For the lower quantiles, there is up to a 40% reduction in the relation between streamflow and crop areas at the Toudaoguai Station. The results of this study are significant scientifically and practically in management of water resources and agricultural irrigation and also matter for enhancement of human knowledge concerning hydrological processes of the Yellow River Basin under the influences of human activities and climatic changes.