文献类型：期刊文献

英文题名：Correcting land surface temperature from thermal imager by considering heterogeneous emissivity

作者：Yan, Wenjie[1] Jiang, Jiawei[1] He, Lanwu[1] Zhao, Wenli[2,3] Nair, Richard[3,4] Wang, Xu[5] Xiong, Yujiu[1,6]

第一作者：Yan, Wenjie

通信作者：Xiong, YJ[1];Wang, X[2]

机构：[1]Sun Yat Sen Univ, Sch Civil Engn, Zhuhai 519082, Guangdong, Peoples R China;[2]Columbia Univ, Dept Earth & Environm Engn, New York, NY 10027 USA;[3]Max Planck Inst Biogeochem, Jena, Germany;[4]Trinity Coll Dublin, Sch Nat Sci, Dublin, Ireland;[5]Chinese Acad Forestry, Res Inst Trop Forestry, Guangzhou 510520, Peoples R China;[6]Sun Yat Sen Univ, Ctr Water Resources & Environm, Guangzhou 510275, Peoples R China

年份：2024

卷号：129

外文期刊名：INTERNATIONAL JOURNAL OF APPLIED EARTH OBSERVATION AND GEOINFORMATION

收录：;Scopus(收录号：2-s2.0-85189946707);WOS:【SCI-EXPANDED(收录号:WOS:001230542500001)】；

基金：We gratefully acknowledge the financial support from National Key Research and Development Program of China (2021YFE0117100) and the National Natural Science Foundation of China (42071395) .

语种：英文

外文关键词：Land surface temperature; Land surface emissivity; Thermal imager; Heterogeneous surface; RGB image; Vegetation index

摘要：It is fundamental to obtain accurate land surface temperature (LST) to study surface energy process. Infrared thermal imagers are commonly used for deriving LST on the basis of radiance measurements. However, when deriving LST from brightness temperature of a blackbody in thermal imagers, thermal imagers only allow setting a fixed land surface emissivity (LSE). This causes uncertainty in retrieving thermal infrared (TIR) temperature from heterogeneous surfaces with varied LSE, such as those covered in vegetation. Corrections can be made using the Normalized Vegetation Index (NDVI). However, commercial thermal imagers provide only red (R), green (G), and blue (B) bands without a near infrared band so NDVI cannot be calculated on the same instrument and is commonly not available. We propose an alternative method to estimate LSE using RGB-based vegetation index. Thereafter the estimated LSE was used to correct the TIR temperature derived from the fixed LSE. An experiment was conducted to validate the proposed correcting method. The results show that 1) the corrected LST values were closer to the ground truth, with a mean absolute error (MAE) of 0.41 +/- 0.34 degrees C, whereas the MAE was 0.75 +/- 0.56 degrees C for the uncorrected LST; 2) the more heterogeneous the surface, the greater the difference between the corrected and uncorrected LST values, indicating the necessity of LST correction when applying thermal imagers over heterogeneous surface.