Structure and Long-term Memory of Discharge Series in Yangtze River
长江干流径流的时序结构与长期记忆

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.