Abstract: The simulation of light scattering characteristics of dust aerosol particles is mainly affected by shape models. Based on the size distribution information of dust aerosol particles provided by the Optical Properties of Aerosols and Clouds (OPAC) package, the light scattering characteristics of group dust aerosol particles are numerically simulated to study their wavelength dependency. Three incident wavelengths of 1064 nm, 532 nm and 355 nm are used for calculating the depolarization ratios of different super-ellipsoid dust particles, and the simulation results show the depolarization ratios of 0.317, 0.397 and 0.446 for each wavelength respectively. Compared with the lidar measurements, the simulation depolarization ratio at 1064 nm wavelength shows the highest consistence, followed by the simulation results at 532 nm wavelength. However, the simulation depolarization ratio at 355 nm wavelength has large bias with the lidar measurements, which may be caused by the same number of the dipoles used for all wavelengths and needs to be investigated in the future. The methodology and non-spherical models used in this study will greatly contribute to our deeper understandings on the wavelength dependence of the depolarization properties of the dust aerosol and guide the development of multi-wavelength polarization lidar. In addition, multi-wavelength polarization measurements will also provide a unique technique to study the mixing state and the evolution of the pollution aerosols.

Key words: non-spherical particle, super-ellipsoid model, dust aerosol, multi-wavelength, depolarization ratio