用陆地卫星TM6数据演算地表温度的单窗算法

Mono-window Algorithm for Retrieving Land Surface Temperature from Landsat TM6 data

陆地卫星 TM数据 (TM6)热波段表示地表热辐射和地表温度变化。长期以来 ,从 TM6数据中演算地表温度通常是通过所谓大气校正法。这一方法需要估计大气热辐射和大气对地表热辐射传导的影响 ,计算过程很复杂 ,误差也较大 ,在实际中应用不多。根据地表热辐射传导方程 ,推导出一个简单易行并且精度较高的演算方法 ,把大气和地表的影响直接包括在演算公式中。该算法需要用地表辐射率、大气透射率和大气平均温度 3个参数进行地表温度的演算。验证表明 ,该方法的地表温度演算较高。当参数估计没有误差时 ,该方法的地表温度演算精度达到 <0 .4℃ ,在参数估计有适度误差时 ,演算精度仍达 <1 .1℃。因该方法适用于仅有一个热波段的遥感数据 ,故称为单窗算法。

Landsat TM data has a thermal band (TM6) to monitor the thermal radiance and surface temperature of the earth. For a long time, retrieval of surface temperature from TM6 data is done through the method called atmospheric correction, which requires the estimate of atmospheric thermal radiance and absorption. The computation is complicated and the accuracy is strongly subjected to the estimate, hence has few applications in real world. In this paper, a new method with simple computation and high accuracy is developed on the basis of thermal radiance transfer equation of the ground. The impacts of both atmosphere and the emitted ground on the thermal radiance transfer of the ground are directly involved into the proposed algorithm, which requires 3 essential parameters for the retrieval: emissivity, transmittance and atmospheric average temperature. Validation indicates that the accuracy of the algorithm is high up to <0.4℃ for the estimate of the essential parameters with no errors and <1.1℃ for the estimate moderate errors. Since the method is applicable for the remote sensing data with only one thermal band, it has been termed as mono window algorithm.