A new method for estimating aerosol mass flux in the urban surface layer using LAS technology

Abstract

Abstract. Atmospheric aerosol greatly influences human health and the natural environment, as well as the weather and climate system. Therefore, atmospheric aerosol has attracted significant attention from society. Despite consistent research efforts, there are still uncertainties in understanding its effects due to poor knowledge about aerosol vertical transport caused by the limited measurement capabilities of aerosol mass vertical transport flux. In this paper, a new method for measuring atmospheric aerosol vertical transport flux is developed based on the similarity theory of surface layer, the theory of light propagation in a turbulent atmosphere, and the observations and studies of the atmospheric equivalent refractive index (AERI). The results show that aerosol mass flux can be linked to the real and imaginary parts of the atmospheric equivalent refractive index structure parameter (AERISP) and the ratio of aerosol mass concentration to the imaginary part of the AERI. The real and imaginary parts of the AERISP can be measured based on the light-propagation theory. The ratio of the aerosol mass concentration to the imaginary part of the AERI can be measured based on the measurements of aerosol mass concentration and visibility. The observational results show that aerosol vertical transport flux varies diurnally and is related to the aerosol spatial distribution. The maximum aerosol flux during the experimental period in Hefei City was 0.017 mg m−2 s−1, and the mean value was 0.004 mg m−2 s−1. The new method offers an effective way to study aerosol vertical transport in complex environments.