Estimation of forest leaf area index and clumping index from the Global Positioning System (GPS) satellite carrier-to-noise-density ratio (C/N-0)

doi:10.1080/2150704X.2019.1692386

	Estimation of forest leaf area index and clumping index from the Global Positioning System (GPS) satellite carrier-to-noise-density ratio (C/N-0)
	Zhang, Yinghui 1,2; Fang, Hongliang 1,2; Ma, Li 1,2; Ye, Yongchang 1,2; Wang, Yao 1,2
刊名	REMOTE SENSING LETTERS
	2020-02-01
卷号	11 期号:2 页码:146-155
ISSN号	2150-704X
DOI	10.1080/2150704X.2019.1692386
通讯作者	Zhang, Yinghui(zhangyh.17b@igsnrr.ac.cn)
英文摘要	Forest leaf area index (LAI) and clumping index (CI) are critical structural parameters to study the biomass, biogeochemical cycles, ecological simulation, and radiation transfer in a forest system. The ground-based measurements by traditional methods are costly, time-consuming, and are sensitive to variations in solar illumination conditions. Global Positioning System (GPS) satellites transfer L-band signals, and the presence of the forest canopy leads to an increase in noise. The GPS satellite's signal strength is generally described by the carrier-to-noise-density ratio (C/N-0). This study explores the potential of using the GPS satellite C/N-0 to estimate forest canopy structural parameters. We performed experiments at 16 forest plots in northeastern China. LAI, CI, and canopy closure were estimated by digital hemispherical photography (DHP) using the CAN_EYE software. The GPS satellite C/N-0 was recorded with a modified smartphone application, GPSTest. The relationship between the forest canopy structural parameters and satellite C/N-0 was analyzed for those observations with satellite elevation angle (SEA) > 30 degrees. The results show that both the true LAI and the effective LAI have strong linear and polynomial correlation with C/N-0 and the coefficient of determination (R-2) is larger than 0.7. CI is linearly related to C/N-0(R-2 = 0.56). The linear relationship between the canopy closure and C/N-0 is much lower (R-2= 0.28). Accounting for the SEA effect, LAI can be estimated with R-2 > 0.8, and CI with R-2 = 0.6. LAI and CI can be well estimated from C/N-0 when the SEA effect is accounted for. In general, the GPS C/N-0 provides an alternative method to estimate forest canopy structural parameters.
资助项目	National Natural Science Foundation of China [NSFC][41531174] ; National Natural Science Foundation of China [NSFC][41471295] ; National Key Research and Development Program of China[2016YFA0600201]
WOS关键词	ACCURACY ; LAI ; FIELDS
WOS研究方向	Remote Sensing ; Imaging Science & Photographic Technology
语种	英语
出版者	TAYLOR & FRANCIS LTD
WOS记录号	WOS:000496902900001
资助机构	National Natural Science Foundation of China [NSFC] ; National Key Research and Development Program of China
内容类型	期刊论文
源URL	[http://ir.igsnrr.ac.cn/handle/311030/132052]
专题	中国科学院地理科学与资源研究所
通讯作者	Zhang, Yinghui
作者单位	1.Chinese Acad Sci, Inst Geog Sci & Nat Resources Res, State Key Lab Resources & Environm Informat Syst, Beijing 100101, Peoples R China 2.Univ Chinese Acad Sci, Beijing, Peoples R China
推荐引用方式 GB/T 7714	Zhang, Yinghui,Fang, Hongliang,Ma, Li,et al. Estimation of forest leaf area index and clumping index from the Global Positioning System (GPS) satellite carrier-to-noise-density ratio (C/N-0)[J]. REMOTE SENSING LETTERS,2020,11(2):146-155.
APA	Zhang, Yinghui,Fang, Hongliang,Ma, Li,Ye, Yongchang,&Wang, Yao.(2020).Estimation of forest leaf area index and clumping index from the Global Positioning System (GPS) satellite carrier-to-noise-density ratio (C/N-0).REMOTE SENSING LETTERS,11(2),146-155.
MLA	Zhang, Yinghui,et al."Estimation of forest leaf area index and clumping index from the Global Positioning System (GPS) satellite carrier-to-noise-density ratio (C/N-0)".REMOTE SENSING LETTERS 11.2(2020):146-155.