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    国产高分辨率热红外数据城市地表温度反演及其应用

    A method for inversion of urban land surface temperature and its application in domestic high-resolution thermal infrared data

    • 摘要: 与自然地表相比,城市地表的几何结构更加复杂,像元内部的多次散射效应和邻近效应对城市地表温度(land surface temperature, LST)反演结果的影响不可忽视。该文提出了一种耦合机器学习和改进的温度/发射率分离(temperature and emissivity separation, TES)的城市 LST 反演算法,并将该方法应用于我国SDGSAT-1热红外数据中。该算法主要包括3个方面: 首先,基于XGBoost(eXtreme Gradient Boosting)算法反演SDGSAT-1城市冠层亮温; 其次,考虑城市几何结构,提出了一种基于天空可视因子(sky view factor, SVF)的TES算法,实现了城市LST的高精度反演; 最后,评估了算法的准确性,并将该方法应用于北京城区。结果显示,使用 XGBoost 算法和分裂窗算法均方根误差(root mean squared error, RMSE)分别约为 0.2 K 和 1.2 K; 在有/无水汽数据支持下,城市LST RMSE分别为0.36 K和0.73 K,3个波段的地表发射率(land surface emissivity,LSE)RMSE分别为0.020/0.026,0.018/0.023和0.020/0.023。改进前后的TES算法反演结果差值范围约为0~1.86K。

       

      Abstract: Compared to natural surfaces, urban surfaces have more complex geometric structures, leading to significant impacts of the multiple scattering effect within pixels and the neighborhood effect on the inversion results of urban land surface temperature (LST). This study proposed a novel urban LST inversion algorithm that integrates machine learning and an enhanced temperature and emissivity separation (TES) method. Finally, the proposed algorithm was applied to China’s SDGSAT-1 thermal infrared data. The algorithm comprises three key steps: First, the inversion of urban canopy brightness temperature from SDGSAT-1 data was conducted using the eXtreme Gradient Boosting (XGBoost) algorithm. Second, an enhanced TES algorithm based on the sky view factor (SVF) was developed to account for urban geometry, enabling high-precision urban LST inversion. Third, the accuracy of the inversion algorithm was assessed and applied to the urban area of Beijing. The results demonstrate that inversion using an XGBoost algorithm and a split-window algorithm yielded root mean squared errors (RMSEs) of approximately 0.2 K and 1.2 K, respectively. The LST RMSEs with and without available water vapor data were determined at 0.36 K and 0.73 K, respectively; and the LSE RMSEs under three bands were 0.020/0.026, 0.018/0.023, and 0.020/0.023, respectively. The differences in the LST inversion results derived using the original and improved TES algorithm ranged from 0 to 1.86 K.

       

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