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| Titel |
Characterization of Atmospheric Ions at the High Altitude Station Jungfraujoch (Switzerland) |
| VerfasserIn |
Carla Frege, Federico Bianchi, Heikki Junninen, Jasmin Tröstl, Ugo Molteni, Erik Herrmann, Mikko Sipilä, Josef Dommen, Markku Kulmala  , Urs Baltensperger |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250105843
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| Publikation (Nr.) |
 EGU/EGU2015-5431.pdf |
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| Zusammenfassung |
| Understanding ion composition in the atmosphere is of high interest since ions control the
electrical properties of the atmospheric medium, participate in ion-catalysed and
ion-molecule reactions and contribute to physico-chemical interactions, including
ion-induced nucleation (Arnold, 2008). In the last decade, the interest in atmospheric ions has
increased because of the potential impact of the ion-aerosol-cloud interaction on
climate (Hirsikko et al., 2011). Therefore, several laboratory and field measurements
have been performed trying to understand the precise role of ions in new particle
formation.
The free troposphere represents an interesting region with no immediate contribution
from biogenic or anthropogenic sources, low pollution and low temperatures, where new
particle formation can make an important contribution to the total particle number
concentration. Thus, the characterization of ions in this region of the atmosphere is an
important step to understand new particle nucleation.
In August 2013 we started measurements at the Jungfraujoch (JFJ, 3580 m asl; 46.55ºN,
7.98ºE) in the Swiss Alps to investigate the composition of atmospheric ions in the lower free
troposphere for around 9 months.
The instrument employed was an Atmospheric Pressure Interface Time-of-Flight Mass
Spectrometer (TOFWERK AG, Thun Switzerland) for ion characterization in positive and
negative mode (alternately). We will present an overview of the major positively and
negatively charged inorganic, organic and halogenated ions. We will also present back
trajectories calculated with two different models: HYSPLIT for air transport and dispersion,
and FLEXPART for surface residence time, along with correlations with the abundance of
specific ions. As measurements were conducted continuously over a long period we were
able to compare ion compositions under different conditions of solar radiation,
presence or absence of clouds and wind direction/ air mass origin and to evaluate
correlations with nucleation events. Diurnal variations of ion composition and correlations
between ion species provided additional information on transport and formation of ion
precursors.
References
Arnold, F. (2008). Atmospheric ions and aerosol formation. Space Science Reviews,
137(1-4), 225–239. doi:10.1007/s11214-008-9390-8
Hirsikko, A., Nieminen, T., Gagné, S., Lehtipalo, K., Manninen, H. E., Ehn, M., /¦
Kulmala, M. (2011). Atmospheric ions and nucleation: a review of observations.
Atmospheric Chemistry and Physics, 11(2), 767–798. doi:10.5194/acp-11-767-2011 |
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