A simple analytical function for bidirectional reflectance

Journal Article · Sun Nov 01 04:00:00 EST 1992 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/92JD01624· OSTI ID:6117229

Ahmad, S P; Deering, D W ^[1]

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1. Hughes-STX Corp., Lanham, MD (United States) NASA, Goddard Space Flight Center, Greenbelt, MD (United States)

A simple bidirectional reflectance model based on physical scattering laws is developed to calculate the bidirectional reflectance of a wide variety of surfaces. Chandrasekhar's radiative transfer solution, obtained for the anisotropically scattering semi-infinite medium, is used to compute the multiple-scattered radiances. However, since the radiative transfer solution does not take architectural effects into consideration, we adopt Hapke's (1986) approach and add an empirical term to explain the hot-spot phenomenon and use Cox and Munk's (1954) formulation to take into account the specular reflection. The physical parameters of the model are retrieved from bidirectional reflectance measurements. For each surface, only one set of model parameters is needed for application to all illumination and viewing geometries. The validity of the model is established by comparing the computed and measured reflectances for sets of viewing and illumination angles that were not included in the inversion algorithm. Good agreement is shown between the model-computed and the observed reflectances for dense prairie vegetation canopies, a sparse desert scrub community, a plowed agricultural field, and an alkali flat. 71 refs.

• Research Organization: National Aeronautics and Space Administration, Greenbelt, MD (United States). Goddard Space Flight Center
• OSTI ID: 6117229
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 97:D17; ISSN JGREA2; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540120* -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (1990-)
ANALYTIC FUNCTIONS
CORRECTIONS
ENERGY BUDGETS
ENERGY TRANSFER
FUNCTIONS
HEAT TRANSFER
MATHEMATICAL MODELS
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
RADIANT HEAT TRANSFER
REMOTE SENSING
SPECTRAL REFLECTANCE