长江干流径流的时序结构与长期记忆

Structure and Long-term Memory of Discharge Series in Yangtze River

基于宜昌、汉口、大通3个典型控制站的长期月径流序列,本文采用奇异谱分析方法、消除波动趋势法(DFA)等手段,识别长江干流径流序列的趋势、突变、周期振荡等时序结构及其长期记忆特征。主要结论有:①长江干流径流序列存在明显的准15年周期振荡特征,该周期振荡1970s以来受到某种扰动而弱化;②宜昌站径流序列于1926年、1970年发生两次突变,均以径流减少为特征;汉口站径流序列于1955a发生突变,也以径流减少为特征;大通站径流于1955年、1988年发生两次突变,前者以径流减少为特征,后者以增加为特征;③长江干流月径流序列存在较强的确定性成分,长期记忆特征明显;集水面积越大,径流序列的长期记忆越强,表现出明显的记忆累积效应。

Based on the long-term monthly discharge series of Yichang, Hankou and Datong stations, this paper has explored the discharge series structure of periodicity, trend and abrupt changes as well as its long-term momery with Singular Spectum Analysis, and Detrended Fluctuation Analysis in employment. The results revealed that： 1） there is a significant 15a periodicity in the discharge series of the Yangtze River, and the 15a periodicity has been disturbed since the 1970s; 2） two abrupt and negative changes of Yichang series respectively in 1926 and 1970 have been detected in Hankou series in 1954; two abrupt changes occurred in Datong series respectively in 1955 and 1988, the former negative and the latter positive; and 3） the performance of DFA revealed a long memory in the discharge series of the Yangtze River, and the larger the upslope contributing area is, the stronger the long memory, which exhibits a cumulative effect.