额尔齐斯河中游鄂木斯克站径流变化特征研究

Runoff Change Characteristics of Omsk Station in Middle Reaches of Irtysh River

根据额尔齐斯河中游鄂木斯克水文站77年的逐月实测径流资料,采用径流年际变化、年内各月占年径流百分比、年内不均匀系数、年内分配完全调节系数、集中度及变化幅度等指标,分析了额尔齐斯河中游径流年际变化特征和年内分配规律。结果表明,受上游水利工程的影响,额尔齐斯河中游鄂木斯克站年径流量呈显著下降趋势;径流年内分配不均匀性减小,集中度降低,集中期的长期变化有所提前;非汛期径流量占年径流总量的比例增加,汛期径流量占年径流总量的比例减少,径流量年内分配渐趋均匀。

This paper studies the characteristics of inter-annual variation and intra-annual distribution of runoff in the middle reaches of the Irtysh River,which are analyzed by using 77 years monthly runoff data observed at the Omsk Hydrologic Station.The analysis is conducted by using different indexes,including annual runoff variation,monthly runoff ratio,annual runoff non-uniform coefficient,annual runoff overall adjustment coefficient,runoff concentration ratio and changing amplitude.The results show that due to the impact of upper reservoirs,the annual runoff in the middle reaches of the Irtysh River has a significant decrease;the inhomogeneity of runoff distribution and ratio of concentration decrease;the concentration period of the runoff at the Omsk Station is advanced gradually based on the long term data;the water quantity proportion of dry season increases and the wet season decreases;the annual runoff distribution in Irtysh River becomes homogeneous gradually.