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The solar zenith angle dependence of desert albedo
Author(s) -
Wang Zhuo,
Barlage Michael,
Zeng Xubin,
Dickinson Robert E.,
Schaaf Crystal B.
Publication year - 2005
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2004gl021835
Subject(s) - solar zenith angle , albedo (alchemy) , environmental science , bidirectional reflectance distribution function , moderate resolution imaging spectroradiometer , spectroradiometer , zenith , atmospheric sciences , remote sensing , soil science , reflectivity , geology , physics , satellite , optics , art , astronomy , performance art , art history
Most land models assume that the bare soil albedo is a function of soil color and moisture but independent of solar zenith angle (SZA). However, analyses of the Moderate Resolution Imaging Spectroradiometer (MODIS) Bidirectional Reflectance Distribution Function (BRDF) and albedo data over thirty desert locations indicate that bare soil albedo does vary with SZA. This is further confirmed using the in situ data. In particular, bare soil albedo normalized by its value at 60° SZA can be adequately represented by a one‐parameter formulation (1 + C)/(1 + 2C * cos(SZA)) or a two‐parameter formulation (1 + B 1 * f 1 (SZA) + B 2 * f 2 (SZA)). Using the MODIS and in situ data, the empirical parameters C, B 1 , and B 2 are taken as 0.15, 0.346 and 0.063. The SZA dependence of soil albedo is also found to significantly affect the modeling of land surface energy balance over a desert site.