Accounting for particle non-sphericity in photopolarimetric remote sensing of desert dust

Abstract

A possibility of using spheroids, for modeling light scattering of desert dust aerosol is discussed. For fast and accurate simulations of optical properties of polydisperse randomly oriented spheroids, the look-up tables of phase matrices, extinction and absorption were computed for 35 narrow size bins covering aerosol size parameters from ~ 0.3 to ~ 280. This numerical tool has been integrated into an algorithm fitting the polarimentric laboratory measurements. The fitting of the phase matrices measured by Volten et al. 2001 has shown that spheroids can closely reproduce the desert dust light scattering. Then a model of spheroids was successfully tested in the retrievals of aerosol from intensity and polarization measured by AERONET groundbased sun/sky radiometers. Key words: Non-spherical aerosol particles, randomly oriented spheroids