Effect of three-dimensional canopy architecture on thermal infrared exitance

James Alan Smith; Jerrell R. Ballard Jr.; Jeffrey A. Pedelty

doi:10.1117/1.601527

1 November 1997 Effect of three-dimensional canopy architecture on thermal infrared exitance

James Alan Smith, Jerrell R. Ballard Jr., Jeffrey A. Pedelty

Optical Engineering, Vol. 36, Issue 11, (November 1997). https://doi.org/10.1117/1.601527

We present a theoretical study of the effects of threedimensional canopy structure on directional thermal infrared exitance. A physics-based model employing steady-state energy budget formulations is used to compute scene element temperatures. Two approaches are then used to combine soil and vegetation contributions to the composite scene response. One method uses a plane-parallel abstraction of canopy architecture to estimate canopy view factors for weighting of soil and vegetation emission terms. The second approach employs computer graphics and rendering techniques to estimate 3-D canopy view factors and scene shadows. Both approaches are applied to a test agricultural scene and compared with available measurements. The models correctly estimate hemispherically averaged thermal infrared exitance to within experimental error with root-mean-square errors of 15.3 W m-2 for the 1-D model and 12.5 W m-2 for the 3-D model. However, the 1-D model systematically underestimates exitance at high sun angles. Explicit modeling of canopy 3-D row structure indicates potential directional anisotropy in brightness temperature of up to 14°C.

Citation Download Citation

James Alan Smith, Jerrell R. Ballard Jr., and Jeffrey A. Pedelty "Effect of three-dimensional canopy architecture on thermal infrared exitance," Optical Engineering 36(11), (1 November 1997). https://doi.org/10.1117/1.601527

Published: 1 November 1997

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available