Inferring spectral surface albedo from bidirectional reflectance measurements

Abstract

Spectral surface albedo is obtained by the numerical integration of bidirectional reflectance using an eight‐point Gaussian integration technique. A simple bidirectional surface reflectance model has been used to generate the reflectance over the geometric conditions required by the integration scheme. Model parameters are obtained through inversion of the model against the measurements performed over that surface for various viewing and illumination angles. The method has been tested over bare soil, annual grassland and hard wheat in the visible and near‐infrared region of solar spectrum. A very good agreement is observed between the modeled and measured value of the albedo both in the visible and near‐infrared over the studied cover types. The technique is particularly suitable for the multidirectional airborne sensor ASAS or future multidirectional satellite sensors like MISR.