利用树轮资料重建通天河流域518年径流量

利用长江源区曲麻莱、治多的树木年轮宽度资料,通过分析树木生长与流量变化的关系,重建了长江源区通天河流域直门达水文站1485年以来年径流量的变化,并进行了变化特征分析。结果表明:在重建的518年中,直门达水文站年径流量最显著的丰水期发生在19世纪前半叶,最显著的枯水期发生在17世纪的后半叶。特丰水年有96年,偏丰水年有117年,特枯水年有86年,偏枯水年有81年,正常水年有138年。重建序列存在43年、37年、32年、5年和2年左右的显著周期。

A 518-year Runoff Reconstruction of Tongtian River Basin Using Tree-ring Width Chronologies

Using the tree-ring width chronologies in Qumalai and Zhiduo, this study investigated the relationships between tree growth and annual runoff of Tongtian River, and reconstructed the runoff series since 1485 AD at Zhimenda hydrologic station, which is located on Tongtian River Basin in the source region of the Yangtze River. The variation of reconstructed runoff series was also analyzed. The results showed that the distinct high-flow period of annual runoff in Zhimenda hydrologic station occurred in the first 50 years of the 19th century, and the low-flow one occurred in the latter half of the 17th century. There are 96 years with extremely high annual runoff, and 117 years with above-average annual runoff. Moreover, the numbers of extremely low runoff years and below-average runoff years are 86 and 81, respectively. There are 138 years with normal annual runoff. The significant cycles of 43, 37, 32, 5, and 2 years exist in the reconstructed runoff series.