A water quality prediction model based on signal decomposition and ensemble deep learning techniques

Abstract

Accurate water quality predictions are critical for water resource protection, and dissolved oxygen (DO) reflects overall river water quality and ecosystem health. This study proposes a hybrid model based on the fusion of signal decomposition and deep learning for predicting river water quality. Initially, complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN) is employed to split the internal series of DO into numerous internal mode functions (IMFs). Subsequently, we employed multi-scale fuzzy entropy (MFE) to compute the entropy values for each IMF component. Time-varying filtered empirical mode decomposition (TVFEMD) is used to further extract features in high-frequency subsequences after linearly aggregating the high-frequency sequences. Finally, support vector machine (SVM) and long short-term memory (LSTM) neural networks are used to predict low- and high-frequency subsequences. Moreover, by comparing it with single models, models based on ‘single layer decomposition-prediction-ensemble’ and combination models using different methods, the feasibility of the proposed model in predicting water quality data for the Xinlian section of Fuhe River and the Chucha section of Ganjiang River was verified. As a result, the combined prediction approach developed in this work has improved generalizability and prediction accuracy, and it may be used to forecast water quality in complicated waters. HIGHLIGHTS Quadratic modal decomposition of water quality data to extract more informative features.; High-frequency and low-frequency sequences were separately predicted using the appropriate deep-learning models, respectively.; The model proposed in this study has more accurate point prediction and interval prediction results compared to other models.;

Keywords

• dissolved oxygen (do)
• long short-term memory
• multi-scale fuzzy entropy
• support vector machine
• time-varying filtered empirical mode decomposition
• water quality prediction