Aerosol optical characteristics in the yellow sand events observed in May, 1982 at Nagasaki-part II models

Abstract

Phase functions of yellow sand particles were measured by a polar nephelometer during 24 April–11 May, 1982 at Nagasaki, Japan. They suggested a strong nonsphericity of the particles, which can be reconstructed by the semi-empirical theory of Pollack and Cuzzi or by Mie particles with large fictitious absorption. Spectral extinction cross section, single scattering albedo, asymmetry factor and backscattering phase function were estimated using the volume spectra retrieved from data of several instruments including the polar nephelometer data. Volume loading of yellow sand particles at the observation site was estimated as 666 l/km2 at the maximum stage of the yellow sand event of 4-6 May and 183 l/km2 for the secondary maximum of 8 May. Using two estimates of the absorption index (0.01 and a model variable with wavelengths), these values show that solar radiative heating from 0.08 to 0.4°/day can be expected in the atmosphere over considerably wide area in one yellow sand event.