Estimation of optical parameters of yellow sand dust clouds over land surface

The optical parameters of the hazy yellow sand dust over the Takula Makan desert in China and the surface reflectance were estimated, using multi-viewing reflectances and polarizations at the wavelength 443nm in several points selected from ADEOS/POLDER data taken on April 10, 1997. In this case, it was assumed that the land surface is the diffuse reflector and the number size distribution of yellow sands is represented by the Junge power-law. The optical parameters of dust clouds and the ground reflectance were determined such that the relative absolute error between the observed reflectance and polarization and those obtained from the simulation of radiative transfer in the atmosphere-ground system is minimum. As a result, it was found that the refractive index of yellow sand dust is 1.36 to 1.45, the optical thickness of dust clouds is 0.44 to 0.54, the index of Junge power-law is -4.2 to -5.0 and the surface reflectance is 0.1 to 0.17.