A new parametrization for ambient particle formation over coniferous forests and its potential implications for the future

Autor: B. Bonn, M. Boy, M. Kulmala, A. Groth, K. Trawny, S. Borchert, S. Jacobi
Jazyk: angličtina
Rok vydání: 2009
Předmět:
Zdroj: Atmospheric Chemistry and Physics, Vol 9, Iss 20, Pp 8079-8090 (2009)
Druh dokumentu: article
ISSN: 1680-7316
1680-7324
75944588
Popis: Atmospheric new particle formation is a general phenomenon observed over coniferous forests. So far nucleation is either parameterised as a function of gaseous sulphuric acid concentration only, which is unable to explain the observed seasonality of nucleation events at different measurement sites, or as a function of sulphuric acid and organic molecules. Here we introduce different nucleation parameters based on the interaction of sulphuric acid and terpene oxidation products and elucidate the individual importance. They include basic trace gas and meteorological measurements such as ozone and water vapour concentrations, temperature (for terpene emission) and UV B radiation as a proxy for OH radical formation. We apply these new parameters to field studies conducted at conducted at Finnish and German measurement sites and compare these to nucleation observations on a daily and annual scale. General agreement was found, although the specific compounds responsible for the nucleation process remain speculative. This can be interpreted as follows: During cooler seasons the emission of biogenic terpenes and the OH availability limits the new particle formation while towards warmer seasons the ratio of ozone and water vapour concentration seems to dominate the general behaviour. Therefore, organics seem to support ambient nucleation besides sulphuric acid or an OH-related compound. Using these nucleation parameters to extrapolate the current conditions to prognosed future concentrations of ozone, water vapour and organic concentrations leads to a significant potential increase in the nucleation event number.
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