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| Titel |
Factors influencing the contribution of ion-induced nucleation in a boreal forest, Finland |
| VerfasserIn |
S. Gagné, T. Nieminen, T. Kurtén, H. E. Manninen, T. Petäjä, L. Laakso, V.-M. Kerminen, M. Boy, M. Kulmala  |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 10, no. 8 ; Nr. 10, no. 8 (2010-04-21), S.3743-3757 |
| Datensatznummer |
250008369
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| Publikation (Nr.) |
 copernicus.org/acp-10-3743-2010.pdf |
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| Zusammenfassung |
| We present the longest series of measurements so far (2 years and 7 months)
made with an Ion-DMPS at the SMEAR II measurement station in
Hyytiälä, Southern Finland. We show that the classification into
overcharged (implying some participation of ion-induced nucleation) and
undercharged (implying no or very little participation of ion-induced
nucleation) days, based on Ion-DMPS measurements, agrees with the fraction
of ion-induced nucleation based on NAIS measurements. Those classes are
based on the ratio of ambient charged particle to steady-state charged
particle concentration, known as the charging state. We analyzed the
influence of different parameters on the contribution of ion-induced
nucleation to the total particle formation rate. We found that the fraction
of ion-induced nucleation is typically higher on warmer, drier and sunnier
days compared to colder days with less solar radiation and a higher relative
humidity. Also, we observed that bigger concentrations of new particles were
produced on days with a smaller fraction of ion-induced nucleation.
Moreover, sulfuric acid saturation ratios were smaller for days with a
bigger fraction of ion-induced nucleation. Finally, we propose explanations
on how these different parameters could influence neutral and ion-induced
nucleation, and show that the different mechanisms seem to take place at the
same time during an event. For example, we propose that these observed
differences could be due to high temperature and low vapors' saturation
ratios (water and sulfuric acid) increasing the height of the energy barrier
a particle has to reach before it can grow and thus limiting neutral
nucleation. |
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