1966~2005年泾河流域径流系数的变化特征

Variation Characteristics of Runoff Coefficients of Jinghe River Basin During 1966-2005

为分析径流系数在泾河流域的时空变化,进一步探讨人类活动及自然因素变化对降水转化为径流的影响,利用泾河流域1966~2005年日均降水和径流数据,基于回归方程与Mann-Kendall非参数统计检验方法,分析8个支流的径流系数变化特征及其与降水的关系。结果表明,泾河流域各支流均径流系数差异显著,其中泾河干流和汭河的年径流系数较大,分别为0.138、0.147,其他各支流的均小于0.1,其中环江和合水川的最小,分别为0.014、0.032。1966~2005年,除环江和东川支流的年径流系数呈上升状态外,其他支流的均呈下降状态,以泾河干流、汭河及洪河支流下降较为显著;月径流系数具有季节变化规律;各支流年径流系数均存在突变点,其中四个支流开始突变时间在1990年代以后;径流系数一定程度上受年降水量的影响,但大多支流影响不显著。各支流年径流系数空间差异主要由自然环境因素引起,而时间变化趋势受人类活动影响较多。

In order to understand the temporal and spatial variation of runoff coefficient in the Jinghe River Basin,and further discuss the influences of human activities and natural factors on the transformation of precipitation into runoff,based on the regressive method and Mann-Kendall trend test technique,the features of runoff coefficients and relevant relations with precipitation across 8 tributaries were analyzed using the daily precipitation and runoff data during the period of 1966 to 2005 in the Jinghe River Basin.The results show that annual average runoff coefficients of Jinghe River trunk stream and Ruihe River with stony mountain area was larger with 0.138 and 0.147 respectively,the other tributaries with less than 0.1,and especially that of Huanjiang and Heshuichuan was the minimum with 0.014 and 0.032 respectively;From 1966 to 2005,except for increasing trend of annual average runoff coefficient of Huanjiang and Dongchuan tributaries,that of other tributaries showed declining trend,with significantly decreasing trend of that of Jing River main stream,Rui River and Hong River.The monthly runoff coefficient had seasonal variation.The time series of annual average runoff coefficient of each tributary had a abrupt change point,among which four tributaries started to change abruptly after 1990s.Moreover,annual precipitation had a certain influence on the runoff coefficient,but the influence of most tributaries was not significant.Finally,the spatial difference of annual runoff coefficient of each tributary was mainly caused by natural environmental factors,while the temporal variation trend was mainly influenced by human activities.