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Proceedings Paper

Responses of plant biochemical substances to reflectance spectra at leaf and canopy scales
Author(s): Runhe Shi; Huifang Zhang; Juan Sun; Wei Gao; Dafang Zhuang; Zheng Niu
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Paper Abstract

Plants cover more than 70% of our earth's land surface and play an important role in the exchange of materials and energy between land and atmosphere. The biochemical substances existing in leaves have been proven to be critical factors in influencing, or even controlling, this exchange by means of various physiological processes, including photosynthesis, evaportranspiration, litter decomposition, etc. Compared to traditional wet chemistry methods, estimation of their contents through leaf and canopy reflectance spectra has become a rapid, efficient, and promising method over the past few decades, which had been physically based on the selective absorption features of a particular substance. This paper discusses the responses of plant biochemical substances to the reflectance spectra at both leaf and canopy scales. We use a leaf optical model PROSPECT and a leaf-canopy coupled optical model PROSAIL to generate large amounts of leaf and canopy spectra. Both of these models contain three biochemical parameters: cab-chlorophyll concentration, Cw-equivalent leaf water thickness, and Cm-dry matter concentration. Local and global sensitivity analysis (SA) methods are used on the simulated spectra to differentiate their contributions to the outcome spectra at both scales so as to investigate their scale effects. Results show that the maximum sensitivities of chlorophyll and water are much higher than that of dry matter at leaf scale, and they tend to decrease at canopy scale because canopy shape, soil, and incident/reflected geometric factors have a large influence on canopy spectra. However, the sensitivity of dry matter exceeds the maximum sensitivity of mesophyll structure parameters at canopy scale and becomes the top contributor at the beginning of near infrared.

Paper Details

Date Published: 10 September 2008
PDF: 8 pages
Proc. SPIE 7083, Remote Sensing and Modeling of Ecosystems for Sustainability V, 70830X (10 September 2008); doi: 10.1117/12.794088
Show Author Affiliations
Runhe Shi, East China Normal Univ. (China)
Institute of Geographical Sciences and Natural Resources Research (China)
Huifang Zhang, East China Normal Univ. (China)
Juan Sun, East China Normal Univ. (China)
Wei Gao, East China Normal Univ. (China)
Colorado State Univ. (United States)
Dafang Zhuang, Institute of Geographical Sciences and Natural Resources Research (China)
Zheng Niu, Institute of Remote Sensing Applications (China)


Published in SPIE Proceedings Vol. 7083:
Remote Sensing and Modeling of Ecosystems for Sustainability V
Wei Gao; Hao Wang, Editor(s)

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