Estimation of terrestrial albedo via BRDF model considering terrain effect

Abstract

In this paper, we examine the terrain effect into terrestrial albedo estimation. Terrestrial albedo is one of the most important parameters in terms of understanding global heat balance. The existing approach for estimating terrestrial albedo starts with the estimation of parameters of bidirectional reflectance distribution function (BRDF) model from measurements observed at different geometry. Then, narrowband albedos are estimated from the BRDF model parameters, and finally the broadband albedo is estimated via narrowband-to-broadband conversion. The previous researches do not consider the terrain effect for generating the terrestrial albedo. The experiments using in-situ measurements show that the BRDF model transforming the geo-coordinate of the reflectance of the shadowed terrain generates the best accuracy. The improvement of the accuracy by the terrain effect correction is limited, and thus it is concluded that further investigation using more in-situ data and simulated data is necessary for operational products.