Thermal IR Exitance Model of a Plant Canopy
Abstract
A 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 correspond within 2 deg C. Simulation results suggested that canopy geometry can significantly influence the effective radiant temperature recorded at varying sensor view angles.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 15, 1981
- Accession Number
- ADA097900
Entities
People
- D. S. Kimes
- J. A. Smith
- L. E. Link
Organizations
- National Aeronautics and Space Administration