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Thermal IR exitance model of a plant canopyA thermal IR exitance model of a plant canopy based on a mathematical abstraction of three horizontal layers of vegetation was developed. Canopy geometry within each layer is quantitatively described by the foliage and branch orientation distributions and number density. Given this geometric information for each layer and the driving meteorological variables, a system of energy budget equations was determined and solved for average layer temperatures. These estimated layer temperatures, together with the angular distributions of radiating elements, were used to calculate the emitted thermal IR radiation as a function of view angle above the canopy. The model was applied to a lodgepole pine (Pinus contorta) canopy over a diurnal cycle. Simulated vs measured radiometric average temperatures of the midcanopy layer corresponded with 2 C. Simulation results suggested that canopy geometry can significantly influence the effective radiant temperature recorded at varying sensor view angles.
Document ID
19810039921
Document Type
Reprint (Version printed in journal)
Authors
Kimes, D. S. (NASA Goddard Space Flight Center Earth Resources Branch, Greenbelt, Md., United States)
Smith, J. A. (Colorado State University Fort Collins, Colo., United States)
Link, L. E. (U.S. Army, Environmental Laboratory, Vicksburg Miss., United States)
Date Acquired
August 11, 2013
Publication Date
February 15, 1981
Publication Information
Publication: Applied Optics
Volume: 20
Subject Category
EARTH RESOURCES AND REMOTE SENSING
Funding Number(s)
CONTRACT_GRANT: DACW39-77-C-0073
CONTRACT_GRANT: DAAG29-78-0045
Distribution Limits
Public
Copyright
Other