Asian-dust monitoring from 11 ìm TB using the concept of polarized reflectivities at the planar surface

It has been shown that the relationship between polarized reflectivities over the planar surface can be analytically expressed, providing potential applicability for remote sensing of surface properties, when combined with window channel measurements by satellite. This research attempts to retrieve the distribution and proxy intensity of Asian dust as a point of application by decomposing unpolarized light into polarized reflectivities at the assumed planar surface. It is demonstrated that the derived refractive indices under the clear-sky condition are substantially different from the Asian dust case, indicating that the contrast of refractive index between the clear sky and dust area could be used for determining the dust boundary. Furthermore, a proxy dust intensity can be determined from the derived refractive index over the dust area. The method has been applied to the MODIS window channel measurements, and results show that it is better than the method of using the brightness temperature difference between two window channels.