关键词: 径流量;输沙量;模态分解;长江;洞庭湖;鄱阳湖;

Abstract: In order to analyze trend of annual runoff and sediment load in the Changjiang River and its two river-connected lakes, Dongting Lake and Poyang Lake, we adopted modal decomposition method to extract variation characteristic of 19 major hydrological stations in the Changjiang River, Dongting Lake and Poyang Lake during 1956～2018.The results showed that predominant periods of 8 and 20 years were discovered in the runoff series.On the basis of the principal component(capturing more than roughly 90% total energy),total change ratios of runoff and sediment loads during the last 63 years were evaluated.For the runoff, absolute total change ratios were 2%～10% and 10%～20% for the Changjiang River and Poyang Lake respectively; while for the sediment load, they were around 90%.However, the change rate of flow and sediment in Dongting Lake were much larger, especially for the three outlets on the Jingjiang River reach(over 140%).

Key words: runoff; sediment load; modal decomposition; Changjiang River; Dongting Lake; Poyang Lake;