Directional Radiance Distributions Above And Witihn A Forest Canopy

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https://ieeexplore.ieee.org/abstract/document/688629

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https://doi.org/10.1109/IGARSS.1990.688629
 http://hdl.handle.net/11603/33333

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UMBC GESTAR II

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Author/Creator ORCID

https://orcid.org/0000-0001-9801-1610

Date

1990-05-20

Type of Work

conference papers and proceedings
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Citation of Original Publication

Deering, D.W., and T.F. Eck. “Directional Radiance Distributions Above And Witihn A Forest Canopy.” 10th Annual International Symposium on Geoscience and Remote Sensing, May 1990, 879–82. https://doi.org/10.1109/IGARSS.1990.688629.

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This work was written as part of one of the author's official duties as an Employee of the United States Government and is therefore a work of the United States Government. In accordance with 17 U.S.C. 105, no copyright protection is available for such works under U.S. Law.
Public Domain

Subjects

Optical sensors
Anisotropic magnetoresistance
Bidirectional control
Area measurement
Distribution functions
Earth
Land surface
Radiometry
Remote monitoring
Satellite broadcasting

Abstract

A multidirectional field radiometer was adapted for measuring directional radiances both above and below a boreal forest canopy to examine the total forest canopy system optical-reflective radiative transfer characteristics and to validate plant canopy models. Analyses of the reflected radiances above the canopy reveal a highly anisotropic bidirectional reflectance distribution function (BRDF) with a sub­stantial forwardscatler but a considerably stronger backscatter. The characteristics of the forest BRDF vary with solar zenith angle, as has been observed to be the usual case in all other green plant canopies previously examined. However, the anisotropy was found to be considerably greater at the larger solar zenith angles for the Maine spruce-hemlock forest than has been observed for other land surfaces, at least for the limited range of solar zeniths available in September. But at the smaller solar zenith angles, the forest was found to have slightly less anisotropy in the near-infrared spectral band than a scrub oak plant community and less anisotropy than a prairie grassland. Keywords: Bidirectional reflectance, BRDF, boreal forest, anisotropy, transmittance.