A deep ensemble learning framework for forecasting root zone soil moisture in semi-arid regions of South Bihar
摘要
Accurate forecasting of root zone soil moisture (RZSM) is crucial for effective groundwater management, irrigation planning, and drought mitigation in semi-arid agrarian regions such as South Bihar. Traditional hydrological models mostly struggle to figure out the nonlinear temporal dynamics inherent in soil moisture data. This study proposes a hybrid deep ensemble learning framework that leverages the strengths of six deep neural networks (LSTM, Bi-LSTM, GRU, Bi-GRU, RNN, and CNN) as base models, with eXtreme Gradient Boosting (XGBoost) employed as a meta-learner in a stacked ensemble architecture. Each model is independently trained on Groundwater Root Zone Soil Wetness (GWETROOT) time series data (Jan 1985 to June 2025), and their predictions are aggregated using XGBoost to generate a robust final forecast. The study utilizes daily RZSM data (GWETROOT, surface to 100 cm depth) obtained from the NASA POWER project, which provides satellite- and model-based gridded estimates. The performance of all models was evaluated across five districts in Bihar (Arwal, Aurangabad, Gaya, Jehanabad, and Nawada) using standard statistical metrics including MAE, MAPE, RMSE, MSE, and