Development of a New BRDF-Resistant Vegetation Index for Improving the Estimation of Leaf Area Index

	Development of a New BRDF-Resistant Vegetation Index for Improving the Estimation of Leaf Area Index
	Zhang, Su 1; Liu, Liangyun 1; Liu, Xinjie 1; Liu, Zefei 1
刊名	REMOTE SENSING
	2016
卷号	8 期号:11
关键词	DAMAGE ASSESSMENT GEOGRAPHIC INFORMATION
通讯作者	Liu, LY (reprint author), Chinese Acad Sci, Inst Remote Sensing & Digital Earth, Key Lab Digital Earth Sci, Beijing 100094, Peoples R China.
英文摘要	The leaf area index (LAI) is one of the most important Earth surface parameters used in the modeling of ecosystems and their interaction with climate. Numerous vegetation indices have been developed to estimate the LAI. However, because of the effects of the bi-directional reflectance distribution function (BRDF), most of these vegetation indices are also sensitive to the effect of BRDF. In this study, we aim to present a new BRDF-resistant vegetation index (BRVI), which is sensitive to the LAI but insensitive to the effect of BRDF. Firstly, the BRDF effects of different bands were investigated using both simulated data and in-situ measurements of winter wheat made at different growth stages. We found bi-directional shape similarity in the solar principal plane between the green and the near-infrared (NIR) bands and between the blue and red bands for farmland soil conditions and with medium chlorophyll content level. Secondly, the consistency of the shape of the BRDF across different bands was employed to develop a new BRDF-resistant vegetation index for estimating the LAI. The reflectance ratios of the NIR band to the green band and the blue band to the red band were reasonably assumed to be resistant to the BRDF effects. Nevertheless, the variation amplitude of the bi-directional reflectance in the solar principal plane was different for different bands. The divisors in the two reflectance ratios were improved by combining the reflectances at the red and green bands. The new BRVI was defined as a normalized combination of the two improved reflectance ratios. Finally, the potential of the proposed BRVI for estimation of the LAI was evaluated using both simulated data and in-situ measurements and also compared to other popular vegetation indices. The results showed that the influence of the BRDF on the BRVI was the weakest and that the BRVI retrieved LAI values well, with a coefficient of determination (R-2) of 0.84 and an RMSE of 0.83 for the field data and with an R-2 of 0.97 and an RMSE of 0.25 for the simulated data. It was concluded, therefore, that the new BRVI is resistant to BRDF effect and is also promising for use in estimating the LAI.
学科主题	Remote Sensing
类目[WOS]	Remote Sensing
收录类别	SCI
语种	英语
WOS记录号	WOS:000388798400067
内容类型	期刊论文
源URL	[http://ir.radi.ac.cn/handle/183411/39218]
专题	遥感与数字地球研究所_SCI/EI期刊论文_期刊论文
作者单位	1.Chinese Acad Sci, Inst Remote Sensing & Digital Earth, Key Lab Digital Earth Sci, Beijing 100094, Peoples R China 2.Univ Chinese Acad Sci, Beijing 100049, Peoples R China 3.Xian Univ Sci & Technol, Coll Geometr, Xian 710054, Peoples R China
推荐引用方式 GB/T 7714	Zhang, Su,Liu, Liangyun,Liu, Xinjie,et al. Development of a New BRDF-Resistant Vegetation Index for Improving the Estimation of Leaf Area Index[J]. REMOTE SENSING,2016,8(11).
APA	Zhang, Su,Liu, Liangyun,Liu, Xinjie,&Liu, Zefei.(2016).Development of a New BRDF-Resistant Vegetation Index for Improving the Estimation of Leaf Area Index.REMOTE SENSING,8(11).
MLA	Zhang, Su,et al."Development of a New BRDF-Resistant Vegetation Index for Improving the Estimation of Leaf Area Index".REMOTE SENSING 8.11(2016).