OPTICAL PROPERTIES OF KOSA AEROSOLS ESTIMATED FROM THE MULTI-SPECTRAL POLARIZATION

摘要

Polarization measurements of the sky radiation by PSR-1000 at a ground station when the yellow sand dust (Asian dust) came flying to the Kanazawa city, Japan from the deserts in the northern part of China were made. The PSR-1000 is the multi-spectral polarimeter and has the same wavelength regions (443 nm, 490 nm, 565 nm, 670 nm, 765 nm and 865 nm) as the ADEOS/POLDER sensor. First of all, the wavelength dependency of degrees of polarization is examined and it is shown that the wavelength dependency for polarization will be due to the size distribution of dust particles transported from the deserts in China. Next, a new method for estimating optical properties, such as the optical thickness, the number size distribution and the refractive index, of yellow sand dust and the background reflectance from degrees of polarization measured by PSR-1000 is described. Finally, this method was applied to the polarization data acquired on March 13, 2000 and April 14, 2002.