Formation, growth, and properties of atmospheric aerosol particles and cloud droplets

Abstract

Formation and growth of atmospheric aerosol particles and their physico-chemical properties have been examined using both aerosol and cloud models, and by conducting field experiments in the Finnish Arctic. Several routes for atmospheric particle production via homogeneous nucleation are proposed Sulphuric acid - water nucleation is studied in more detail, and occasions of new particle production in the Finnish Arctic are identified. The bulk aerosol in the Finnish Arctic is rather acidic with the least acidic particles originating from the ocean, and the most acidic ones from the East. We are able to show that the nucleation characteristics of these two types of particles are different. Acidic vapors are in addition shown to contribute to the formation and growth of cloud droplets strongly enough to change the optical thickness of an idividual cloud under certain conditions.