基于长短期记忆网络的大气污染浓度预测方法

Forecasting air pollution concentration using long Short-Term Memory Networks

  • 摘要: 提出了多源时空特征与季节趋势分解融合的深度学习预测模型.模型利用图卷积神经网络 (graph convolutional network,GCN)和注意力机制的时域卷积网络(temporal convolutional network,TCN),分别提取细颗粒物(particulate matter 2.5,PM2.5)质量浓度的空间依赖特征与时序特征;二者经哈达玛积融合后,与随机森林(random forest,RF)筛选出的关键气象及污染物因素进行特征拼接,形成多源时空特征.再采用季节趋势分解算法,将目标站点的 PM2.5质量浓度序列分解为趋势、季节和残差子序列;将多源时空特征与各子序列分别拼接,输入长短期记忆(long short-term memory,LSTM)网络−序列到序列(sequence to sequence,STS)−注意力机制模型进行预测,得到最终PM2.5质量浓度的预测结果.将多源时空特征季节趋势分解模型命名为M5,移除时间、空间、时空特征融合和季节趋势分解特征提取模块后得到的变体模型分别命名为M1、M2、M3和M4.相较M1~M4,M5在第1 h预测中均方根误差(root mean square error,RMSE)值分别降低了13.1%、16.6%、14.8%和9.7%,在第3 h预测中分别降低了18.7%、12.0%、9.6%和13.1%,在第6 h预测中分别降低了15.8%、8.7%、10.7%和20.5%;相较M1~M4,在每个滑动窗口末端观测时刻后,M5预测的第1~6 h的误差平方汇总计算的整体RMSE降低了17.2%、10.8%、10.3%和16.5%.

     

    Abstract: A deep learning prediction model integrating multi-source spatiotemporal features and seasonal trend decomposition was proposed. The model utilizes the graph convolutional network (GCN) and the time-domain convolutional network with attention mechanism to extract the spatial-dependent and temporal features of particulate matter 2.5 (PM2.5) concentration; after the Hadamard product fusion of the two, they are concatenated with the key meteorological and pollutant factors selected by random forest to form multi-source spatiotemporal features. Then, the seasonal trend decomposition algorithm is used to decompose the PM2.5 concentration sequence of the target site into trend, season, and residual sub-sequences; the multi-source spatiotemporal features are concatenated with each sub-sequence respectively, and input into the long short-term memory (LSTM) network - sequence-to-sequence - attention mechanism model for prediction, obtaining the final prediction result of PM2.5 concentration. The multi-source spatiotemporal feature seasonal trend decomposition model is named M5. The variant models obtained after removing the time, space, spatiotemporal feature fusion and seasonal trend decomposition feature extraction modules are named M1, M2, M3, and M4. Compared with M1 to M4, the root mean square error (RMSE) values of M5 in the 1-hour prediction are reduced by 13.1%, 16.6%, 14.8%, and 9.7% respectively; in the 3-hour prediction, they are reduced by 18.7%, 12.0%, 9.6%, and 13.1% respectively; in the 6-hour prediction, they are reduced by 15.8%, 8.7%, 10.7%, and 20.5% respectively; compared with M1 to M4, in each sliding window end observation time, the overall RMSE of the error square summary calculation of M5’s prediction from the 1st to the 6th hour is reduced by 17.2%, 10.8%, 10.3%, and 16.5% respectively.

     

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