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Directional reflectance factor distributions of a cotton row cropThe directional reflectance factor distribution spanning the entire exitance hemisphere was measured for a cotton row crop (Gossypium barbadense L.) with 39 percent ground cover. Spectral directional radiances were taken in NOAA satellite 7 AVHRR bands 1 and 2 using a three-band radiometer with restricted 12 deg full angle field of view at half peak power points. Polar co-ordinate system plots of directional reflectance factor distributions and three-dimensional computer graphic plots of scattered flux were used to study the dynamics of the directional reflectance factor distribution as a function of spectral band, geometric structure of the scene, solar zenith and azimuth angles, and optical properties of the leaves and soil. The factor distribution of the incomplete row crops was highly polymodal relative to that for complete vegetation canopies. Besides the enhanced reflectance for the antisolar point, a reflectance minimum was observed towards the forwardscatter direction in the principle plane of the sun. Knowledge of the mechanics of the observed dynamics of the data may be used to provide rigorous validation for two- or three-dimensional radiative transfer models, and is important in interpreting aircraft and satellite data where the solar angle varies widely.
Document ID
Document Type
Reprint (Version printed in journal)
Kimes, D. S. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Newcomb, W. W. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Schutt, J. B. (NASA Goddard Space Flight Center Earth Resources Branch, Greenbelt, MD, United States)
Pinter, P. J., Jr. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Jackson, R. D. (U.S. Department of Agriculture, Water Conservation Laboratory, Phoenix AZ, United States)
Date Acquired
August 12, 2013
Publication Date
April 1, 1984
Publication Information
Publication: International Journal of Remote Sensing
Volume: 5
ISSN: 0143-1161
Subject Category
Distribution Limits