Analysis the Reasons for Low Water Level Emerged in Poyang Lake Based on Hydrological Long-Time Series Decomposition by EMD

The wet and dry periods with multi-time scales of hydrological long-time series in Poyang Lake and Yangtze River were analyzed based on the method of Empirical Mode Decomposition (EMD). The results indicated that the variation of wet and dry periods of Yangtze River and Poyang Lake had diversified representation, and consistency with the meso and short scale periods. The reasons for the low water level emerged early and the lowest water level had breakthrough the history were explained.