Optimal bulk optical model linking the backscattering properties and microphysical properties of dust plumes

Sensitivities of the bulk backscattering properties of mineral dust aerosols (lidar ratio and depolarization ratio) to the microphysical properties (in particular, size and shape) are examined based on TAMUdust2020, a comprehensive single-scattering property database of irregular dust aerosol particles. We develop the bulk mineral dust particle models based on size-resolved particle ensembles with randomly distorted shapes and spectrally resolved complex refractive indices, which are constrained with in-situ observations reported in the literature. The results indicate that the lidar ratio is more sensitive to particle shape than particle size, while the depolarization ratio is noticeably sensitive to particle size. These simulated bulk backscattering properties of typical mineral dust particles with effective radii of 0.53 m are reasonably consistent with high spectral resolution lidar (HSRL) observations made during several field campaigns. The present dust bulk optical property models are useful for applications to remote sensing of dust aerosol properties involving lidar observations.