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CNN-SVR用于MAX-DOAS预测对流层NO2廓线
Prediction of Tropospheric NO2 Profile Using CNN-SVR-Based MAX-DOAS
【摘要】 提出一种基于卷积神经网络(CNN)和支持向量回归机(SVR)的多轴差分光学吸收光谱(MAX-DOAS)对流层NO2垂直分布预测方法。将2019年南京站点采集的原始MAX-DOAS数据通过QDOAS软件拟合获取O4和NO2差分斜柱浓度,结合基于最优估算的气溶胶和痕量气体廓线反演算法——PriAM算法反演了对流层NO2廓线,并将其作为预测模型的输出。此外,通过平均影响值方法进行预测模型输入变量的选择,确定了MAX-DOAS数据、温度、气溶胶光学厚度和低云覆盖率为模型的最佳输入变量。通过实验优化网络结构和参数,最终建立预测模型在测试集与PriAM的平均百分比误差仅为9.14%,与单独建立的CNN、SVR、反向传播模型相比,平均百分比误差分别降低了8.22%、6.00%、32.28%。因此,CNN-SVR能够利用MAX-DOAS数据对对流层NO2廓线进行有效预测。
【Abstract】 This study proposes a method based on a convolutional neural network(CNN) and support vector regression machine(SVR) for predicting the vertical distribution of NO2 in the troposphere by multi-axis differential optical absorption spectroscopy(MAX-DOAS) technology. Taking the Nanjing site as an example, we obtain the O4 and NO2 differential slant column density(dSCD) according to the raw MAX-DOAS data collected by QDOAS fitting in 2019, invert the tropospheric NO2 profile by combining the optimal estimation-based aerosol and trace gas profile inversion algorithmPriAM, and use the profile as the output of the prediction model. In addition, the input variables of the prediction model are selected by the mean impact value method, with MAX-DOAS data, temperature, aerosol optical thickness, and low cloud coverage finally identified as the optimal input variables for the model. Furthermore, the network structure and parameters are optimized through experiments, and the average percentage error of the final CNN-SVR prediction model in the test set with PriAM is only 9. 14%, which is 8. 22%, 6. 00%, and 32. 28% lower than that of the separately constructed CNN, SVR, and backpropagation models, respectively. Therefore, CNN-SVR can effectively predict tropospheric NO2 profiles by using MAX-DOAS data.
【Key words】 atmospheric optics; convolutional neural network; support vector regression machine; multi-axis differential absorption spectroscopy; tropospheric NO2 profile;
- 【文献出处】 光学学报 ,Acta Optica Sinica , 编辑部邮箱 ,2022年24期
- 【分类号】X831;TP18
- 【下载频次】154