Estimation of the BRDF of the Earth surface from ADEOS/POLDER data

The ADEOS/POLDER observes the radiances from the target quasi-simultaneously under up to 13 different viewing angles in a single satellite pass. The bidirectional reflectance distribution function (BRDF) for a grassland and a forest from the ADEOS/POLDER data over East Asia taken on April 12, 1997 is estimated. The parameters of the Minnaert´s BRDF model were determined, comparing the apparent reflectances by the POLDER with those obtained from the radiative transfer simulation in the atmosphere-ground system. As a result, it is shown that the BRDF for a grassland is approximately regarded as the diffuse reflector. The BRDF for a forest is somewhat different from that of the grassland. At the near infrared band (910 nm), the surface reflectance of a forest decreases as the viewing angle increases in the forward scattering direction, whereas it somewhat increases as the viewing angle increases in the backward direction