On the Derivation of Geometric Optical Kernels for Directional Thermal Radiation

doi:10.1029/2019EA000895

	On the Derivation of Geometric Optical Kernels for Directional Thermal Radiation
	Liu, Xiangyang 1,2,3; Tang, Bo-Hui 1,2; Li, Zhao-Liang 1,2,3; Zhang, Xia 4; Shang, Guofei 4
刊名	EARTH AND SPACE SCIENCE
	2020
卷号	7 期号:1 页码:13
关键词	thermal radiation directionality geometric optical model kernel function component temperature difference land surface temperature
DOI	10.1029/2019EA000895
通讯作者	Tang, Bo-Hui(tangbh@igsnrr.ac.cn) ; Shang, Guofei(shangguofei@hgu.edu.cn)
英文摘要	The derivation of widely used geometric optical (GO) kernels in bidirectional reflectance distribution function models, that is, LiSparseReciprocal kernel (K-GOLSR) and LiDenseReciprocal kernel, was based on two important assumptions: (1) The shaded components are perfect black and (2) the contributions of two sunlit components are identical. Different from the bidirectional reflectance, thermal radiation directionality effect mainly results from component temperature differences, suggesting the above assumptions are not applicable in most situations. Therefore, this study derived GO kernels for thermal radiation based on temperature differences rather than illumination differences. Specifically, four GO kernels, that is, K-GO4 with considering sunlit/shaded vegetation and sunlit/shaded soil, K-GO3 with considering sunlit/shaded soil and vegetation, K-GO2 with considering vegetation and soil, and K-GOg only considering the hottest sunlit soil, have been developed. By using a comprehensive simulated data set, their performances have been thoroughly evaluated and the comparison with K-GOLSR has also been analyzed in depth. Results showed that (1) K-GO4 had the highest accuracy and K-GO3 was the second; in the case of only two available angles, K-GOg performed best. (2) Variables such as component temperature, component emissivity, solar zenith angle, and the percentage of tree crown cover mainly affected the comparison result between K-GOLSR and K-GO2; K-GOLSR would have a better performance for a scene with a stronger vegetation effect. Moreover, the best values of two structure characteristics, that is, the crown shape parameter b/r and relative height h/b, for these five kernels have been determined, which can provide instruction for practical application. Plain Language Summary Land surface temperature is a key variable for a variety of geoscientific studies. However, because of the heterogeneity of land surface, this important parameter has a significant angular effect. Previous studies mainly learned from directional reflectance models. Therefore, in this study, we developed four geometric optical kernels for correcting directional effect of land surface temperature from the inherent characteristic of thermal radiation. These new kernels not only own clearer physical meaning but also have higher accuracies. Moreover, we also determined the best values of two structure characteristics to provide instruction for practical application.
资助项目	National Natural Science Foundation of China[41871244] ; Innovation Project of LREIS[O88RA801YA] ; China Scholarship Council
WOS关键词	LAND-SURFACE TEMPERATURE ; BIDIRECTIONAL REFLECTANCE ; BRIGHTNESS TEMPERATURE ; DRIVEN MODEL ; EMISSIVITY ; CANOPY ; VALIDATION ; ANISOTROPY ; PRODUCT
WOS研究方向	Astronomy & Astrophysics ; Geology
语种	英语
出版者	AMER GEOPHYSICAL UNION
WOS记录号	WOS:000509311500004
资助机构	National Natural Science Foundation of China ; Innovation Project of LREIS ; China Scholarship Council
内容类型	期刊论文
源URL	[http://ir.igsnrr.ac.cn/handle/311030/131327]
专题	中国科学院地理科学与资源研究所
通讯作者	Tang, Bo-Hui; Shang, Guofei
作者单位	1.Chinese Acad Sci, Inst Geog Sci & Nat Resources Res, State Key Lab Resources & Environm Informat Syst, Beijing, Peoples R China 2.Univ Chinese Acad Sci, Coll Resources & Environm, Beijing, Peoples R China 3.UdS, CNRS, UMR7357, ICube, Illkirch Graffenstaden, France 4.Hebei GEO Univ, Sch Land Resources & Urban Rural Planning, Shijiazhuang, Hebei, Peoples R China
推荐引用方式 GB/T 7714	Liu, Xiangyang,Tang, Bo-Hui,Li, Zhao-Liang,et al. On the Derivation of Geometric Optical Kernels for Directional Thermal Radiation[J]. EARTH AND SPACE SCIENCE,2020,7(1):13.
APA	Liu, Xiangyang,Tang, Bo-Hui,Li, Zhao-Liang,Zhang, Xia,&Shang, Guofei.(2020).On the Derivation of Geometric Optical Kernels for Directional Thermal Radiation.EARTH AND SPACE SCIENCE,7(1),13.
MLA	Liu, Xiangyang,et al."On the Derivation of Geometric Optical Kernels for Directional Thermal Radiation".EARTH AND SPACE SCIENCE 7.1(2020):13.