长江源区径流年内分配时程变化规律分析

Change of Annual Runoff Distribution in the Headwaters of the Yangtze River

在气候变化和人类活动的影响下,河川径流的年内分配特征也发生变化,直接影响人类开发利用和生态环境建设.根据长江源区1956-2000年河流月径流资料,分析了年内分配不均匀系数、完全调节系数、集中度、集中期、变化幅度等特性.结果表明:长江源径流年内分配特征在1960年前后与1988年前后径流年内分配较为相近,1970—1976年与1993年以后径流年内分配较为相近.沱沱河站径流年内分配的不均匀性、集中度以及相对变化幅度都高于直门达站.

With the impact of climate change and increasing the intensity of human activities, the hydrological regime has changed, including annual runoff distribution, which is relating with water resources management and ecological construction. In this paper, the index of unevenness, concentration, and variation have been defined and calculated according to gauge records of runoff in the 1956 --2000. Then the change of annual runoff distribution in the headwaters of the Yangtze River is discussed. It is revealed that： 1） the annual runoff distribution in the 1960s was quite similar to that in the 1988s, while in 1970--1976 it was almost the same to that after 1993. 2） In the Tuotuohe Station, which locates at the upper reaches, the unevenness, concentration rate, relative variation rate and absolute variation rate are higher than that in the Zhimenda Station.