气候变化领域集成服务门户(CCPortal): A multi-angular invariant spectral index for the estimation of leaf water content across a wide range of plant species in different growth stages

CCPortal

DOI	10.1016/j.rse.2020.112230
	A multi-angular invariant spectral index for the estimation of leaf water content across a wide range of plant species in different growth stages
	Li X.; Sun Z.; Lu S.; Omasa K.
发表日期	2021
ISSN	00344257
卷号	253
英文摘要	Plant leaf water content plays a key role in several biogeochemical processes, such as photosynthesis, evapotranspiration, and net primary production. Yet, the accurate estimation of leaf water content using multi-angular reflectance measurements across different plant species is still challenging. This study aims to propose a generic spectral index for accurately estimating equivalent water thickness (EWT) when multi-angular spectral reflection is considered. The index was selected to have the format of a difference ratio using three reflectance factors. The reflectance factor at 410 nm was used to reduce the specular reflection from the leaf surface in the 400–2500 nm range, and the ratio of the wavelengths in the 1268–1285 nm range (at non-water absorption wavelengths) to the wavelengths in the 1339–1346 nm range (at water absorption wavelengths) strengthened the relationship with EWT for all of the sampled plant species. The modified difference ratio (MDR) index, (R1271-R410)/(R1342-R410), was linearly proportional to EWT, with R2 > 0.90, when the leaves reflection data were collected from various viewing angles. However, the relationships between some existing indices (simple difference, simple ratio, normalized difference, double difference index and difference ratio indices) and EWT at the leaf level were weak and unstable for all of the 18 plant species (including 14 broadleaf, 3 shrub, and 1 liana species) at different angles under laboratory and field conditions. Moreover, validation results from six independent datasets (n = 1800) and one modeled dataset (n = 2375) further confirmed that the algorithm derived from the proposed index (based on multi-angular reflectance factors of leaves) was not only effective for EWT estimation across a diverse set of plant species with widely variable leaf structure and water content, but also insensitive to different measurement conditions (leaf clip, integrating spheres or multi-angle measurements). The algorithm developed from this new index is generic, does not require reparameterization for each species, and can be accurately used for nondestructive EWT estimations using a simple handheld laboratory or field instrument, and thus, is convenient for agricultural and ecological studies. © 2020 Elsevier Inc.
英文关键词	Angle-insensitive spectral indices; Equivalent water thickness (EWT); Leaf water content estimation; Multi-angular spectral reflectance factor
语种	英语
scopus关键词	Agricultural robots; Plants (botany); Reflection; Absorption wavelengths; Biogeochemical process; Different growth stages; Equivalent water thickness; Linearly proportional; Measurement conditions; Net primary production; Normalized differences; Water absorption; algorithm; growth form; leaf; reflectance; remote sensing; spectral analysis; water content
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/179017
作者单位	Key Laboratory of Geographical Processes and Ecological Security in Changbai Mountains, Ministry of Education, School of Geographical Sciences, Northeast Normal University, Changchun, 130024, China; Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, 113-8657, Japan; Faculty of Agriculture, Takasaki University of Health and WelfareGunma 370-0033, Japan
推荐引用方式 GB/T 7714	Li X.,Sun Z.,Lu S.,et al. A multi-angular invariant spectral index for the estimation of leaf water content across a wide range of plant species in different growth stages[J],2021,253.
APA	Li X.,Sun Z.,Lu S.,&Omasa K..(2021).A multi-angular invariant spectral index for the estimation of leaf water content across a wide range of plant species in different growth stages.Remote Sensing of Environment,253.
MLA	Li X.,et al."A multi-angular invariant spectral index for the estimation of leaf water content across a wide range of plant species in different growth stages".Remote Sensing of Environment 253(2021).