Thursday, December 8, 2011, 16:00
WBGB/019
U. Baltensperger, PSI
Abstract:
Globally, a significant source of cloud condensation nuclei for cloud
formation is thought to originate from new particle formation (aerosol nucleation).
Despite an extensive research effort, many questions remain about the dominant
nucleation mechanisms. The potential influence of ions from galactic cosmic
rays on the atmospheric aerosol nucleation processes may play an important role
relevant for aerosol production, 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. Similarly, a quantitative
understanding of the dependence of the nucleation rate on the concentration
of the nucleating substances such as gaseous sulfuric acid, ammonia, water
vapor and others has not been reached. This is of relevance for climate as
the atmospheric concentrations of sulfuric acid, ammonia and other nucleating
agents are strongly influenced by anthropogenic emissions.
In this presentation first an overview is given of the potential processes
by which cosmic rays may affect climate and examples of the correlations of
atmospheric and paleo-climatic parameters suggesting this connection are
briefly reviewed. Then, the first results from the CLOUD experiment in
the new aerosol chamber facility at CERN are presented, which recently have
been published in Nature.