黄河源区径流年内分配变化规律分析

河川径流的年内分配特征与特定的径流补给条件关系密切。在气候变化以及人类活动的影响下,河川径流的年内分配特征也发生着相应的变化,直接影响水资源的开发利用以及生态系统的健康。本文根据黄河源区主要测站1952～1997年的月天然径流资料,分析了年内分配不均匀系数、集中度和集中期、变化幅度等特性。结果表明:1)黄河源区径流的年内分配特征20世纪90年代和70年代较为接近,而80年代则与60年代较为接近。2)90年代的径流年内分配特征出现了较大的变化,突出表现在汛期径流量的减少;3)玛曲水文站径流年内分配的不均匀性、集中度以及相对变化幅度都略高于唐乃亥,而绝对变化幅度则较小。

Changes of Annual Runoff Distribution in the Headwater of the Yellow River Basin

Annual runoff distribution is connected with the flow recharge situation.With the impacts of climatic changes and increasing density of human activities, the hydrological regimes have been changed,including changes of annual runoff distribution, which may show effects on water resources management and ecological health.In this paper, indexes of unevenness, concentration, and variation have been defined and calculated according to gauge records of runoff in the last half-century.And then the changes of annual runoff distribution in the headwater of the Yellow River have been discussed.The results show that: 1) the annual runoff distribution in 1990s was quite similar to that of 1970s, while 1980s was almost the same to 1960s; 2) in 1990s, the annual runoff distribution had changed a lot, mainly because of runoff decrease in the wet season (July to Oct.); 3)Maqu station, which locates at the upper reaches, has a higher unevenness, concentration and relative variation rate but a smaller absolute variation rate than that of the Tangnaihai station.It should be noted that the indices used in this paper have correlations between each other, but have reflected the characters of annual runoff distribution by different ways.For further research, it is necessary to develop more suitable indices to describe the essence of the annual flow regime.The causes and effects of annual runoff distribution changes are all important issues for research considerations.