Seasonal Variations in Aerosol Optical Properties with Emphasis on the Effect of Relative Humidity at Seoul and Gosan, Korea

Seasonal variations in aerosol optical properties were studied in company with aerosol chemical compositions using optical and chemical equilibrium models. In Gosan, the optical contribution of water-soluble aerosols was dominant, and the hygroscopic growth possibility was increased by high portion of hydrophilic aerosols and high RH condition. In spring, the observed AODs were high at both the sites even though the aerosol concentrations obtained from ground-based measurements were low because of the influence of dust particles. In summer, we expected the conspicuous hygroscopic growth of water-soluble aerosols together with a sufficient quantity of free water, but the influence of water content was obscure and not dominant. However, if the quantity of water-soluble aerosols was higher than that of the present, free water would be combined with hygroscopic aerosols in summer.