Studies of Atmospheric Aerosol Nucleation in the CLOUD Experiment at CERN
Abstract
The formation of new aerosol particles is a frequent process in the atmosphere but the details of the fundamental mechanisms and involved substances are still under discussion. The CLOUD experiment studies aerosol nucleation and initial growth in a 26 cubic meter stainless steel aerosol chamber at CERN. Here, atmospheric conditions can be simulated with high precision and at sufficiently low levels of background impurities. Nucleation has been studied for several chemical systems including ammonia-sulfuric acid-water and dimethylamine-sulfuric acid-water. Ion-induced nucleation processes are quantified and compared to neutral nucleation by exposing the aerosol chamber to a diverged pion beam from the CERN proton synchrotron and therefore the potential role of cosmic rays for aerosol nucleation can be accessed. A focus of investigations is the molecular composition and abundance levels of neutral and charged clusters by direct observation during the nucleation process. Nucleation rates as a function of compound concentrations and temperature are determined and then parameterized. The nucleation rate parameterizations are implemented in a global aerosol model to investigate the role of the nucleation mechanisms for atmospheric aerosol and CCN populations.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2012
- Bibcode:
- 2012AGUFM.A53U..07C
- Keywords:
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- 0305 ATMOSPHERIC COMPOSITION AND STRUCTURE / Aerosols and particles;
- 0335 ATMOSPHERIC COMPOSITION AND STRUCTURE / Ion chemistry of the atmosphere;
- 3311 ATMOSPHERIC PROCESSES / Clouds and aerosols