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UP: Fachverband Umweltphysik

UP 15: Symposium Einfluss der Sonne auf das Klima der Erde

UP 15.2: Hauptvortrag

Donnerstag, 28. Februar 2013, 14:30–15:00, HS 2

Influence of Galactic Cosmic Rays and solar variability on aerosols, clouds and climate: Results from the CLOUD experiment at CERN — •Joachim Curtius — Institute for Atmosph. & Envir. Sciences, Univ. of Frankfurt/Main, Germany

The potential influence of ions produced from galactic cosmic rays on the formation of new aerosol particles in the atmosphere may play an important role relevant for aerosol properties, cloud formation and climate. Variability of galactic cosmic rays due to modulating influences from the sun therefore may affect (regional) climate on various time scales. A quantitative understanding of the role of ions for atmospheric aerosol formation has not been reached, but also the dependence of aerosol formation on the concentration of the nucleating substances such as gaseous sulfuric acid, ammonia and amines is missing.

Here results from the CLOUD experiment at CERN are presented. CLOUD is a new aerosol and cloud chamber facility at CERN. The chamber can be exposed to a pion beam from CERN to simulate various levels of atmospheric ionization. CLOUD has been set up to investigate aerosol and cloud processes under well-controlled laboratory conditions. We find that cosmic ray ionization substantially increases the nucleation rate of pure sulfuric acid/water particles while charge effects are much less pronounced for ternary systems including ammonia or dimethylamine. The results from the CLOUD experiments have been used to develop a new parameterization of aerosol nucleation which has been included in a global climate model. Impacts of our findings for cloud formation and climate are discussed.