A method to identify abrupt alternation of droughts and floods based on EEOF methodology

The Yangtze river basin is one of the regions with the most severe drought and flood disasters in China. Global warming has increased the frequency of these extreme events, with profound implications for reservoir operation and planning efficiency. Accurate identification of abrupt alternation of drought and flood events is essential for flood control, drought relief, water resource management, and power generation planning in the basin. The study presented in this paper applies the Extended Empirical Orthogonal Function (EEOF) method to identify the dominant precipitation patterns during the main flood season, and examines their relationship with the traditional Short-cycle Drought-Flood Abrupt Alternation Index (SDFAI) to provide scientific support for flood control and drought relief.