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DOI	10.1016/j.rse.2020.112018
	Estimation of boreal forest floor reflectance from airborne hyperspectral data of coniferous forests
	Markiet V.; Mõttus M.
发表日期	2020
ISSN	00344257
卷号	249
英文摘要	In open forest canopies, such as in boreal forests, forest floor can contribute significantly to the observed top of canopy reflectance. In order to retrieve the biophysical properties of the tree layer, correcting for forest floor is essential. Traditionally, the algorithms for retrieval of forest floor reflectance depend on tree layer information such as leaf area index, canopy cover, and site fertility. To overcome these circular dependencies, we propose an algorithm that can be applied only using airborne remote sensing data. We acquired airborne hyperspectral imagery over the Hyytiälä forest research station (61°50′N, 24°17′E) in central Finland on July 3rd in 2015 using a hyperspectral pushbroom line scanner. The image data had a spectral resolution of 4.6 nm, and the spatial resolution was 0.6 m. We developed a linear spectral unmixing algorithm, which is based on the definition of the reflectance factor, taking into account the variation of incident irradiance inside the canopy. The weights of the mixture can be computed from tree canopy gap fractions, a tree species insensitive leaf albedo, and average tree stand reflectance. Canopy gap fractions were retrieved with empirical methods available in scientific literature. The forest floor reflectance in the near-infrared increased with site fertility in agreement with the forest floor field measurements. Moreover, we found that in near infrared, the reflectance of moderately rich and moist upland forests was significantly different from all other fertility classes. Finally, we tested the reflectance decomposition on the photochemical reflectance index (PRI) known to be heavily affected by understory reflectance and canopy structure, and the forest PRI to be decoupled from the PRI of the over- and understory. © 2020
英文关键词	Airborne imaging spectroscopy; Boreal forest; Forest floor BRF; Hyperspectral imaging; Linear spectral unmixing; Photochemical reflectance index; Site fertility class; Sunlit fraction; Understory
语种	英语
scopus关键词	Floors; Incident solar radiation; Infrared devices; Plants (botany); Reflection; Remote sensing; Spectroscopy; Airborne hyperspectral data; Airborne remote sensing; Biophysical properties; Canopy gap fractions; Hyper-spectral imageries; Linear spectral unmixing; Photochemical reflectance index; Scientific literature; Forestry; boreal forest; canopy architecture; canopy gap; coniferous forest; decomposition; estimation method; fertility; forest floor; irradiance; leaf area index; photochemistry; remote sensing; spatial resolution; spectral resolution; understory; Finland
来源期刊	Remote Sensing of Environment
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/179165
作者单位	VTT Technical Research Centre of Finland, P.O. Box 1000, Espoo, FI-02044 VTT, Finland
推荐引用方式 GB/T 7714	Markiet V.,Mõttus M.. Estimation of boreal forest floor reflectance from airborne hyperspectral data of coniferous forests[J],2020,249.
APA	Markiet V.,&Mõttus M..(2020).Estimation of boreal forest floor reflectance from airborne hyperspectral data of coniferous forests.Remote Sensing of Environment,249.
MLA	Markiet V.,et al."Estimation of boreal forest floor reflectance from airborne hyperspectral data of coniferous forests".Remote Sensing of Environment 249(2020).