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Proceedings Paper

A study of fraction of absorbed photosynthetically active radiation characteristics based on SAIL model simulation
Author(s): Li Li; Yongming Du; Yong Tang; Qinhuo Liu
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Paper Abstract

The photosynthetically Active Radiation reached to plant canopy could be divided into two parts that are direct radiation and diffuse radiation. The paths into the vegetation canopy are different of these two kinds of radiation. It makes Fraction of Absorbed Photosynthetically Active Radiation (FPAR) different. So this difference between direct FPAR and diffuse FPAR must be determined to decide whether it should be considered into the FPAR inversion model. In this study, the SAIL model was modified which could output direct FPAR and diffuse FPAR. Then with the change of input parameters such as solar zenith angle, visiblity and LAI, the direct FPAR and diffuse FPAR would be change. When the visibility is set as 5km, 15km and 30km, the contribution of scattering of FPAR on the total FPAR is 52.6%, 29.3% and 21.7%. The error between whole FPAR and direct FPAR is reduced with the increasing of visibility and increased with the reducing of LAI. The maximum relative error is 13.2%. From the simulation analyses, we could see that direct and diffuse FPAR are different with the changes of environment variables. So when modeling of FPAR, the diffuse part cannot be ignored. Direct FPAR and diffuse FPAR must be modeled respectively. This separation will help improve the accuracy of FPAR inversion.

Paper Details

Date Published: 21 November 2012
PDF: 6 pages
Proc. SPIE 8524, Land Surface Remote Sensing, 85242J (21 November 2012); doi: 10.1117/12.977769
Show Author Affiliations
Li Li, State Key Lab. of Remote Sensing Science (China)
Peking Univ. (China)
Yongming Du, State Key Lab. of Remote Sensing Science (China)
Yong Tang, State Key Lab. of Remote Sensing Science (China)
Qinhuo Liu, State Key Lab. of Remote Sensing Science (China)

Published in SPIE Proceedings Vol. 8524:
Land Surface Remote Sensing
Dara Entekhabi; Yoshiaki Honda; Haruo Sawada; Jiancheng Shi; Taikan Oki, Editor(s)

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