Study on inversion of atmospheric aerosol nonsphericity based on satellite and ground observations

Abstract

The lack of aerosol shape data is one of the causes for the uncertainty of aerosol radiative forcing. In this paper, the parameterization of aerosol particle shape is successfully implemented based on the written computer program using satellite and ground observation data. The method can use aerosol optical (microphysical) properties and linear depolarization ratio from multiple data sources for obtaining aspect ratio based on the ellipsoidal model, or aspect ratio and roundness based on the super-ellipsoidal model. Subsequently, the distribution characteristics of aerosol depolarization ratio have been analyzed, the aerosol nonsphericity in global regions have been inverted based on the method, and the solar radiance of different study regions has been calculated according to the aerosol nonsphericity and verified by the sun photometer data. The results show that the aerosol depolarization ratio data is mainly distributed below 6 km. In urban regions, the depolarization ratio is generally below 20%, while in desert regions, it is mostly distributed between 20% and 40%. The aerosol aspect ratio based on the ellipsoidal model obtained by inversion ranges from 1.00 to 1.55 and vary considerably with region, generally less than 1.20 in urban regions and generally greater than 1.20 in desert regions. Meanwhile, the aerosol aspect ratio and roundness based on the super-ellipsoidal model obtained by inversion range from 1.00 to 1.40 and 1.00 to 1.30, respectively. The aspect ratio and roundness in urban regions are distributed between 1.00 and 1.15 (1.10), while in desert regions are generally greater than 1.10. Besides, the calculation results of solar radiance show that the parameterized data of aerosol nonsphericity can provide an effective shape input for aerosol optical modeling.