资源环境科技发展态势分析平台

An experimental setup to study aerosol hygroscopicity is proposed based on the temporal evolution of attenuated backscatter coefficients from a ceilometer colocated with an instrumented tower equipped with meteorological sensors at different heights. This setup is used to analyze a 4.5-year database at the ACTRIS SIRTA observatory in Palaiseau (Paris, France, 2.208 degrees E, 48.713 degrees N; 160 m above sea level). A strict criterion-based procedure has been established to identify hygroscopic growth cases using ancillary information, such as online chemical composition, resulting in 8 hygroscopic growth cases from a total of 107 potential cases. For these eight cases, hygroscopic growth-related properties, such as the attenuated backscatter enhancement factor f(beta) (RH) and the hygroscopic growth coefficient gamma, are evaluated. This study shows that the hygroscopicity parameter gamma is negatively correlated with the aerosol organic mass fraction but shows a positive correlation with the aerosol in-organic mass fraction. Among inorganic species, nitrate exhibited the highest correlation.

This is the first time that hygroscopic enhancement factors are directly retrieved under ambient aerosols using remote-sensing techniques, which are combined with online chemical composition in situ measurements to evaluate the role of the different aerosol species in aerosol hygroscopicity.