Development of a Two-Stage LSTM for Multi-Step Runoff Forecasting Using a XAJ Model and EEMD
摘要
Precise runoff forecasting is important for regional water resources planning. Reliable prediction remains difficult in the middle and lower Yangtze River because traditional hydrological models often underperform, while many machine learning methods act as black boxes. We propose a two-stage long short-term memory (LSTM) approach for multi-step runoff forecasting. The framework integrates the Xinanjiang (XAJ) model, LSTM, ensemble empirical mode decomposition (EEMD), and error correction (EC). This design addresses compatibility issues between hydrological processes and signal decomposition, improving predictive accuracy while retaining physical interpretability. For a 7-day lead time, EC-X-LSTM improves correlation coefficient (r, + 4.63%), Nash–Sutcliffe Efficiency (NSE, + 9.80%), Kling–Gupta Efficiency (KGE, + 2.93%), and Willmott Index (WI, + 2.27%). It also reduces Root Relative Mean Square Error (RRMSE, –54.26%) and Mean Absolute Percentage Error (MAPE, –52.41%). SHAP analysis shows that hybrid model output, dew point temperature, maximum temperature, mean temperature, and reference evapotranspiration are the top five predictors at Datong station. Overall, the method provides a reliable and interpretable tool for short- and medium-term runoff forecasting, offering practical insights for water management in the Yangtze River basin.