汉江上游径流变化趋势及特征分析

南水北调中线工程从汉江中上游的丹江口水库引水,作为调水工程水源区,研究汉江上游的径流变化趋势及特征具有重要意义。采用累积距平法和Mann-Kendall趋势分析法分析典型测站的长系列年径流量变化趋势,采用滑动t检验和有序聚类法分析年径流量突变情况。以汉江上游典型水文站武侯站、洋县站、汉中站和石泉站为例。结果表明:20世纪50年代以来,汉江上游径流量总体呈减少趋势,尤其在20世纪90年代以后减少趋势显著。各站年径流量的变化趋势相似,年代平均径流量存在高低交替的现象。突变分析表明4个水文站径流的突变年份均为1990年。汉江上游径流量减少主要受降水量的减少、社会经济用水的增加及水资源开发利用等方面的影响。

Trends and characteristics of runoff for upper Hanjiang River

The middle route of the South to North Water Transfer Project is originated from Danjiangkou reservoir in the middle and upper reaches of the Hanjiang River. As the water source area of water diversion project, it is of great significance to study the trends and characteristics of runoff in the upper reaches of the Hanjiang River. The trends and variations of annual runoff for typical stations were analyzed using the cumulative anomaly and Mann Kendall methods, and Sliding t test and sequential clustering were used to analyze the change of annual runoff. Taking four hydrological stations including Wuhou, Yangxian, Shiquan, Hanzhong in the upper reaches of Hanjiang River as examples, the results showed that the runoff amount in the upper reaches of Hanjiang River showed a trend of decreasing since 1950s, the decreasing trend was significant especially after 1990s. The changing trend of annual runoff in each station was similar, and the average runoff has the phenomenon of alternating high or low. The abrupt analysis showed that the abrupt points of the runoff for the four stations are all in 1990.The decrease of runoff in the upper reaches of the Hanjiang River was mainly affected by the decrease of precipitation and the increase of water using in social economy.