Aerosol extinction hygroscopic growth proxy based on visibility in Hefei during the winter

Aerosol extinction hygroscopic growth is one of the important parameters to characterize the hygroscopic properties of aerosols, as well as explore the environmental effects of aerosols and evaluate air quality. In this paper, the variation characteristics of aerosol extinction factor, atmospheric visibility (VIS) and relative humidity (RH) were analyzed based on the measurements in Hefei during winter (from December 2021 to January 2022). It is shown that the aerosol extinction coefficient (VIS) is positively (negatively) correlated with RH, especially in high-RH environments where the extinction coefficient (VIS) is extremely high (extremely low). Based on four commonly used empirical parameterization schemes of aerosol extinction hygroscopic growth factor, an empirical model of aerosol extinction hygroscopic growth factor for winter in Hefei is presented. There is no significant difference in the parameterization results of the four models, which are able to express the variation characteristics of aerosol extinction hygroscopic growth with RH, but the simulations of the four models are higher than the observations in high-RH environment.