DocumentCode :
1334185
Title :
An algorithm for the retrieval of albedo from space using semiempirical BRDF models
Author :
Lucht, Wolfgang ; Schaaf, Crystal Barker ; Strahler, Alan H.
Author_Institution :
Dept. of Geogr., Boston Univ., MA, USA
Volume :
38
Issue :
2
fYear :
2000
fDate :
3/1/2000 12:00:00 AM
Firstpage :
977
Lastpage :
998
Abstract :
Spectral albedo may be derived from atmospherically corrected, cloud-cleared multiangular reflectance observations through the inversion of a bidirectional reflectance distribution function (BRDF) model and angular integration. This paper outlines an algorithm suitable for this task that makes use of kernel-based BRDF models. Intrinsic land surface albedos are derived, which may be used to derive actual albedo by taking into account the prevailing distribution of diffuse skylight. Spectral-to-broadband conversion is achieved using band-dependent weighting factors. The validation of a suitable BRDF model, the semiempirical Ross-Li (reciprocal RossThick-LiSparse) model and its performance under conditions of sparse angular sampling and noisy reflectances are discussed, showing that the retrievals obtained are generally reliable. The solar-zenith angle dependence of albedo may be parameterized by a simple polynomial that makes it unnecessary for the user to be familiar with the underlying BRDF model. The algorithm given is that used for the production of a BRDF/albedo standard data product from NASA´s EOS-MODIS sensor, for which an at-launch status is provided. Finally, the algorithm is demonstrated on combined AVHRR and GOES observations acquired over New England, from which solar zenith angle-dependent albedo maps with a nominal spatial resolution of 1 km are derived in the visible band. The algorithm presented may be employed to derive albedo from space-based multiangular measurements and also serves as a guide for the use of the MODIS BRDF/albedo product
Keywords :
albedo; geophysical techniques; remote sensing; terrain mapping; BRDF; albedo; algorithm; angular integration; band-dependent weighting factor; bidirectional reflectance distribution function; diffuse skylight; geophysical measurement technique; inversion; land surface; multiangular reflectance observations; optical imaging; reciprocal RossThick-LiSparse model; retrieval; satellite remote sensing; semiempirical Ross-Li model; semiempirical model; spectral albedo; spectral-to-broadband conversion; terrain mapping; visible; Atmospheric modeling; Bidirectional control; Distribution functions; Land surface; MODIS; Polynomials; Production; Reflectivity; Sampling methods; Spatial resolution;
fLanguage :
English
Journal_Title :
Geoscience and Remote Sensing, IEEE Transactions on
Publisher :
ieee
ISSN :
0196-2892
Type :
jour
DOI :
10.1109/36.841980
Filename :
841980
Link To Document :
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