A Dual-wavelength Lidar Analysis of Dust Aerosol Properties
IT is rather difficult to illustrate the dust aerosol optical properties due to the extremely irregular shape of dust particles. Such irregularity often brings about difficulty in transforming their physical properties (size distribution) into optical properties (scattering phase function) in remote sensing retrieval and atmospheric radiation transfer model. Some recent researches reveal that homogeneous spheroids seem to be an applicable approximate model when particles are not much bigger than the wavelength. However, spheroids in reasonable shape distribution can simulate the scattering matrix of dust particles quite well. The paper attempts to introduce such spheroid model into dual-wavelength lidar retrieval of dust aerosol properties. When the size distribution of dust aerosol is modeled by mono-modal lognormal function with a known complex refractive index, the standard deviation, median radius of the size distribution and lidar ratio of dust aerosol at two wavelengths can be derived from dual-wavelength lidar signal. By applying this method to dual-wavelength lidar at Semi-Arid Climate and Environment Observatory of Lanzhou University (SACOL), preliminary results show that the derived size distributions agree with observed ones by Aerodynamic Particle Size when observed size distributions are close to lognormal distributions. The method is also applied to CALIPSO data and six dust storm cases in Saharan and Taklimakan deserts are explored. When complex refractive indexes of dust aerosol are assumed as mean values, lidar ratios of 532 nm and 1064 nm are respectively 41.4±6.7 and 45.0±3.3.
Dust aerosol Size distribution Dual-wavelength lidar Lidar ratio
Zhiting Wang Lei Zhang
Key Laboratory for Semi-Arid Climate Change of the Ministry of Education,College of Atmospheric Sciences,Lanzhou University,Lanzhou,730000,China
国际会议
西安
英文
80-85
2011-08-17（万方平台首次上网日期，不代表论文的发表时间）