Scattering properties and lidar characteristics of Asian dust particles based on realistic shape models

作者：A. Luna, Zhibo Zhang, Jianyu Zheng, Qianqian Song, Hongbin Yu, Jiachen Ding, Ping Yang, Masanori Saito · 发表于：Atmospheric chemistry and physics · 年份：2025 · DOI：10.5194/acp-25-13359-2025 · 被引用次数：3 · 研究领域：Atmospheric aerosols and clouds、Atmospheric chemistry and aerosols、Atmospheric Ozone and Climate

Abstract. The lidar backscattering properties of Asian dust particles, namely the lidar ratio (S) and backscattering depolarization ratio (δ), were studied using a discrete dipole approximation (DDA) model. The three-dimensional morphology of the dust particles was reconstructed in fine detail using the focused ion beam (FIB) tomography technique. An index based on the symmetry of the scattering matrix was developed to assess the convergence of random orientation computation using DDA. Both S and δ exhibit an asymptotic trend with dust particle size: the S initially decreases, while the δ increases with size, before both approach their asymptotic values. The lidar properties were found to have statistically insignificant dependence on effective sphericity. The presence of strongly absorbing minerals, such as magnetite, can greatly reduce the dust's single-scattering albedo and δ. Utilizing the robust asymptotic trend behavior, two parameterization schemes were developed: one to estimate the δ of a single dust particle given its size and the other to estimate the δ of dust particles with a lognormal particle size distribution given the effective radius. The parameterization scheme was compared with results based on the TAMUdust2020 database, showing hexahedrons to reasonably represent realistic geometries with similar physical properties.