近714年扎曲河流域径流量的重建和变化特征

Reconstruction and Variation of Zhaqu River Runoff in Recent 714 Years

利用采自澜沧江上游杂多地区的树木年轮资料重建了1293-2006年3-9月扎曲河香达水文站平均径流量序列。对重建资料进行订正,并将1955年以前的重建资料与1956-2006年实测序列衔接,应用多窗谱分析和小波分析等方法研究了扎曲河流域过去714年径流量的时间演变及周期、突变特征。结果表明,扎曲河流域径流量有着显著的2~6年为主的高频变化和20~50年为主的低频变化特征,其中ENSO分量是一个最主要的周期分量,QBO分量的振幅呈显著的18~24年缓变包络特征,而年代际分量在19世纪后期到20世纪逐渐增强。过去714年扎曲河流域径流量有12个丰水期及15个枯水期以及3个明显的突变点,且最近的一次突变是发生在20世纪初的负突变。

Based on tree-ring samples collected from Zaduo area in upper reaches of the Lancang River,mean runoff at Xiangda from March to September during 1293- 2006 is reconstructed. After adjust the reconstructed series,Linked the reconstructed series before 1955 and the observation data from 1956 to 2006,the temporal evolution characteristics and abrupt changes of the Zhaqu River runoff in recent 714 years were being studied by using the Multi-Taper Method( MTM) of spectrum and the Smoothing t-test method. The results showthat there exist pronounced high frequency variations of 2 ~ 6 years and lowfrequency variations of 20 ~ 50 years or so.Reconstructed ENSO band is the uppermost components,QBO of time series exhibit significant 18 ~ 24 years modulation both amplitude and frequency,inter-decadal quasi-periods signals gradually strengthened during late19 thcentury to 20 thcentury. The Zhaqu River runoff has experienced obvious 12 high flowperiods and 15 lowflowperiods in the past 714 years,and exists 3 point of abrupt changes,the last abrupt change is negative that occurred at early 20 thcentury.