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Four dimensional mapping of vegetation moisture content using dual-wavelength terrestrial laser scanning.

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).


Recently, terrestrial laser scanning (TLS) has shown potential in measuring vegetation biochemical traits in three dimensions (3D) by using reflectance derived from backscattered intensity data. The 3D estimates can provide information about the vertical heterogeneity of canopy biochemical traits which affects canopy reflectance but cannot be measured from spaceborne and airborne optical remote sensing data. Leaf equivalent water thickness (EWT), a metric widely used in vegetation health monitoring, has been successfully linked to the normalized difference index (NDI) of near and shortwave infrared wavelengths at the leaf level. However, only two previous studies have linked EWT to NDI at the canopy level in field campaigns. In this study, an NDI consisting of 808 and 1550 nm wavelengths was used to generate 3D EWT estimates at the canopy level in a broadleaf mixed-species tree plot during and after a heatwave. The relative error in EWT estimates was 6% across four different species. Temporal changes in EWT were measured, and the accuracy varied between trees, a factor of the errors in EWT estimates on both dates. Vertical profiles of EWT were generated for six trees and showed vertical heterogeneity and variation between species. The change in EWT vertical profiles during and after the heatwave differed between trees, demonstrating that trees reacted in different ways to the drought condition.

Publication metadata

Author(s): Elsherif A, Gaulton R, Mills J

Publication type: Article

Publication status: Published

Journal: Remote Sensing

Year: 2019

Volume: 11

Issue: 19

Pages: 2311

Print publication date: 04/10/2019

Online publication date: 04/10/2019

Acceptance date: 01/10/2019

Date deposited: 17/10/2019

ISSN (electronic): 2072-4292

Publisher: MDPI AG


DOI: 10.3390/rs11192311


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