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    基于深度学习的热红外遥感地表温度和发射率反演优化研究

    Deep learning-based inversion optimization for land surface temperature and emissivity obtained from thermal infrared remote sensing data

    • 摘要: MODIS数据的地表温度(land surface temperature,LST)和地表发射率(land surface emissivity,LSE)广泛应用于气候监测、环境评估和农业灾害等领域,但受云、气溶胶、大气水汽和混合像元等因素影响,精度仍有提升空间。为此,该文提出一种基于深度学习的迭代优化策略,以进一步提升LST和LSE的反演精度。首先,利用辐射传输方程进行物理逻辑推理,确定深度学习输入和输出的变量之间满足参数反演理论和判定条件; 其次,通过MODTRAN4对中分辨率成像光谱仪(moderate resolution imaging spectroradiometer,MODIS)热红外波段进行仿真和迭代优化,验证优化可行性并选择最佳波段组合; 然后,采集5个MODIS热红外波段的亮温、LST和LSE数据,基于Adam优化器构建迭代微调策略,逐步优化深度学习神经网络,获得更精确的LST和LSE产品; 最后,经过优化后重新训练网络,并将其应用于北美地区的MODIS遥感数据反演。模拟数据实验中,5波段组合相比4波段组合,LST反演的平均绝对误差(mean absolute error,MAE)从0.747 5 K降至0.583 5 K,皮尔逊相关系数(Pearson correlation coefficient,PCC)从0.997 7提高至0.998 6,LSE的反演精度也显著提高,且优化后的扰乱模拟数据与实际原始数据之间误差较小。实际采集数据优化显示,经过迭代微调后,LST反演的MAE从1.823 7 K降至1.154 3 K,PCC从0.980 3提高至0.991 8。引入实测数据对模拟数据进行验证,MAE从2.180 4 K降至1.828 0 K,PCC从0.913 5提高至0.941 8,更接近真实值,进一步体现该策略的优化效果。本研究为气候环境等领域提供可靠的数据支撑,具有较广阔的应用前景。

       

      Abstract: The land surface temperature (LST) and land surface emissivity (LSE) derived from the moderate-resolution imaging spectroradiometer (MODIS) data have been widely used for climate monitoring, environmental assessment, and prevention of agricultural disasters. However, their accuracy is insufficient due to the influence of factors such as cloud, aerosol, precipitable water vapor, and mixed pixels. To enhance the inversion accuracy of both LST and LSE, this study proposed a deep learning-based iterative optimization strategy. First, the radiative transfer equation was used for physical logic reasoning to ensure the input and output variables for deep learning meet the parameter inversion theory and judgment conditions. Second, MODTRAN4 was employed to simulate and iteratively optimize the MODIS thermal infrared bands. The feasibility of the optimization was verified, and the optimal band combination was selected. Third, the brightness temperature, LST, and LSE data of five MODIS thermal infrared bands were collected. An iterative fine-tuning strategy was constructed based on the Adam optimizer to gradually optimize the deep learning neural network, thereby obtaining more accurate LST and LSE products. Finally, the optimized network was retrained and applied to the inversion of the MODIS remote sensing data of North America. In the experiments using simulated data, compared to the 4-band combination, the 5-band input for LST inversion led to a mean absolute error (MAE) decreasing from 0.747 5 K to 0.583 5 K and a Pearson correlation coefficient (PCC) increasing from 0.997 7 to 0.998 6. Meanwhile, the LSE inversion accuracy was also significantly enhanced. The optimized disturbance simulation data exhibited a minimal error compared to the actual raw data. The optimization of the actual data shows that through iterative fine-tuning, the LST inversion yielded a MAE decreasing from 1.823 7 K to 1.154 3 K and a PCC increasing from 0.980 3 to 0.991 8. Measured data were then introduced to validate the simulation data, with MAE decreasing from 2.180 4 K to 1.828 0 K and PCC increasing from 0.913 5 to 0.941 8. These results suggest that the simulation data are more close to actual values, further confirming the optimization effects of the strategy. Overall, this study provides reliable data support for fields such as climate and environment, holding broad application prospects.

       

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