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The global distribution of leaf chlorophyll content

Citation

Croft, H and Chen, JM and Wang, R and Mo, G and Luo, S and Luo, X and He, L and Gonsamo, A and Arabian, J and Zhang, Y and Simic-Milas, A and Noland, TL and He, Y and Homolova, L and Malenovsky, Z and Yi, Q and Beringer, J and Amiri, R and Hutley, L and Arellano, P and Stahl, C and Bonal, D, The global distribution of leaf chlorophyll content, Remote Sensing of Environment, 236 Article 111479. ISSN 0034-4257 (2020) [Refereed Article]

Copyright Statement

2019 Elsevier Inc. All rights reserved.

DOI: doi:10.1016/j.rse.2019.111479

Abstract

Leaf chlorophyll is central to the exchange of carbon, water and energy between the biosphere and the atmosphere, and to the functioning of terrestrial ecosystems. This paper presents the first spatially-continuous view of terrestrial leaf chlorophyll content (ChlLeaf) at the global scale. Weekly maps of ChlLeaf were produced from ENVISAT MERIS full resolution (300 m) satellite data using a two-stage physically-based radiative transfer modelling approach. Firstly, leaf-level reflectance was derived from top-of-canopy satellite reflectance observations using 4-Scale and SAIL canopy radiative transfer models for woody and non-woody vegetation, respectively. Secondly, the modelled leaf-level reflectance was input into the PROSPECT leaf-level radiative transfer model to derive ChlLeaf. The ChlLeaf retrieval algorithm was validated using measured ChlLeaf data from 248 sample measurements at 28 field locations, and covering six plant functional types (PFTs). Modelled results show strong relationships with field measurements, particularly for deciduous broadleaf forests (R2 = 0.67; RMSE = 9.25 μg cm-2; p < 0.001), croplands (R2 = 0.41; RMSE = 13.18 μg cm-2; p < 0.001) and evergreen needleleaf forests (R2 = 0.47; RMSE = 10.63 μg cm-2; p < 0.001). When the modelled results from all PFTs were considered together, the overall relationship with measured ChlLeaf remained good (R2 = 0.47, RMSE = 10.79 μg cm-2; p < 0.001). This result is an improvement on the relationship between measured ChlLeaf and a commonly used chlorophyll-sensitive spectral vegetation index; the MERIS Terrestrial Chlorophyll Index (MTCI; R2 = 0.27, p < 0.001). The global maps show large temporal and spatial variability in ChlLeaf, with evergreen broadleaf forests presenting the highest leaf chlorophyll values, with global annual median values of 54.4 μg cm-2. Distinct seasonal ChlLeaf phenologies are also visible, particularly in deciduous plant forms, associated with budburst and crop growth, and leaf senescence. It is anticipated that this global ChlLeaf product will make an important step towards the explicit consideration of leaf-level bioche

Item Details

Item Type:Refereed Article
Keywords:radiative transfer, 4-Scale, SAIL, PROSPECT, leaf biochemistry, MERIS, satellite, remote sensing, leaf physiology, carbon cycle, ecosystem modelling, phenology
Research Division:Engineering
Research Group:Geomatic engineering
Research Field:Photogrammetry and remote sensing
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the environmental sciences
UTAS Author:Malenovsky, Z (Dr Zbynek Malenovsky)
ID Code:139217
Year Published:2020
Funding Support:Australian Research Council (FT160100477)
Web of Science® Times Cited:27
Deposited By:Geography and Spatial Science
Deposited On:2020-06-01
Last Modified:2020-07-09
Downloads:0

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