榆林河多年径流特性分析

Analysis on the Characteristics of Runoff for Years of Yulin River

选取榆林河1974—2006年共33 a的各月出山口来水径流数据作为研究数据。利用显著性检验以及集中度、集中期的分析计算,阐述了榆林河多年平均年内分配和多年年际径流量变化状况。同时,利用Spearman秩次检验方法来检验各月及总的年际变化趋势。结果表明:榆林河多年年际径流量变化具有不显著的波动性,大多年份都属于平水年;多年径流量变化趋势最显著的月份是3月份,最不显著的是5月份;相对变幅最大年份为1998年,其次是1979年,最小年份为2003年;33 a期间,径流年内变化集中度变化趋势与分配系数变化趋势大体上是一致的,并且集中度对径流的变化敏感性更强;2000年以后径流的年内分配格局发生了变化,径流集中期由原来的7、8月份转变为5、6月份。

The main selected data come from each month of 33 years runoff observed from 1974 to 2006 of Yulin River. By using significance test and calculating concentration ratio and concentration period, we analyzed the changing characteristics of annual and inter-annual runoff of Yulin River. In addition, we tested the changing trend of runoff in each month and total year by Spearman rank test method. Results indicate that, the fluctuation of inter-annual runoff of Yulin River is not significant; most years belong to normal flow year. For the changing trend of inter-annual month runoff, the most significance is March, while May is the most inconspicuous month. The maximum relative variation amplitude occurred in 1998, followed by 1979 and the minimum in 2003. During 33 years, the changing trend of concentration ratio of inter-annual runoff is in accordance with that of distribution coefficient ; further more, the concentration ratio is more sensitive to runoff than distribution coefficient. Annual runoff distribution pattern has changed since 2000, with the runoff concentration period transforming from July and August to May and June.