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Lookup NU author(s): Ahmed Elsherif,
Dr Rachel Gaulton,
Professor Jon Mills
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
Satellites can estimate forest canopy moisture content at the landscape level, and thus have been widely utilized in forest health monitoring. However, the calibration and validation of the estimation models can be challenging. Collecting a sufficient number of leaf samples from the canopy top layers in sampling plots that match the pixel size of the sensor is needed, which is a cost, time and effort consuming process. Dual-wavelength Terrestrial Laser Scanning (TLS) has been successfully used in estimating canopy moisture content of individual trees in three dimensions (3D) in several recent studies. Such 3D estimates, if produced at the plot level, can be used in the calibration and validation of satellite forest canopy moisture content estimation models. In this study, forest canopy moisture content, quantified as the leaf Equivalent Water Thickness (EWT), was estimated in 3D at the plot level in a mixed-species deciduous broadleaf forest plot using dual-wavelength TLS intensity data (808 nm near infrared and 1550 nm shortwave infrared wavelengths). The relative error in the EWT estimation was 6%, and the EWT point cloud revealed vertical heterogeneity in the EWT distribution. EWT was 37% higher in the canopy top layers than in the canopy bottom layers. The results obtained in this study showed that dual-wavelength TLS has the potential to be used in operational landscape-scale EWT estimation, and can be a useful tool for the calibration and validation of satellite EWT estimation models.
Author(s): Elsherif A, Gaulton R, Mills JP
Publication type: Article
Publication status: Published
Journal: ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences
Online publication date: 02/09/2020
Acceptance date: 31/08/2020
Date deposited: 24/05/2021
ISSN (print): 2194-9042
ISSN (electronic): 2194-9050
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