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| Titel |
Formation and characteristics of ions and charged aerosol particles in a native Australian Eucalypt forest |
| VerfasserIn |
T. Suni, M. Kulmala  , A. Hirsikko, T. Bergman, L. Laakso, P. P. Aalto, R. Leuning, H. Cleugh, S. Zegelin, D. Hughes, E. Gorsel, M. Kitchen, M. Vana, U. Hõrrak, S. Mirme, A. Mirme, S. Sevanto, J. Twining, C. Tadros |
| 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 ; 8, no. 1 ; Nr. 8, no. 1 (2008-01-14), S.129-139 |
| Datensatznummer |
250005340
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| Publikation (Nr.) |
 copernicus.org/acp-8-129-2008.pdf |
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| Zusammenfassung |
| Biogenic aerosol formation is likely to contribute significantly to the
global aerosol load. In recent years, new-particle formation has been
observed in various ecosystems around the world but hardly any measurements
have taken place in the terrestrial Southern Hemisphere. Here, we report the
first results of atmospheric ion and charged particle concentrations as well
as of new-particle formation in a Eucalypt forest in Tumbarumba, South-East
Australia, from July 2005 to October 2006. The measurements were carried out
with an Air Ion Spectrometer (AIS) with a size range from 0.34 to 40 nm. The
Eucalypt forest was a very strong source of new aerosol particles. Daytime
aerosol formation took place on 52% of days with acceptable data, which
is 2–3 times as often as in the Nordic boreal zone. Average growth rates for
negative/positive 1.5–3 nm particles during these formation events were
2.89/2.68 nmh−1, respectively; for 3-7 nm particles 4.26/4.03, and for
7–20 nm particles 8.90/7.58 nmh−1, respectively. The growth rates for
large ions were highest when the air was coming from the native forest which
suggests that the Eucalypts were a strong source of condensable vapours.
Average concentrations of cluster ions (0.34–1.8 nm) were
2400/1700 cm−3 for negative/positive ions, very high compared to most
other measurements around the world. One reason behind these high
concentrations could be the strong radon efflux from the soils around the
Tumbarumba field site. Furthermore, comparison between night-time and
daytime concentrations supported the view that cluster ions are produced
close to the surface within the boundary layer also at night but that large
ions are mostly produced in daytime. Finally, a previously unreported
phenomenon, nocturnal aerosol formation, appeared in 32% of the analysed
nights but was clustered almost entirely within six months from summer to
autumn in 2006. From January to May, nocturnal formation was 2.5 times as
frequent as daytime formation. Therefore, it appears that in summer and
autumn, nocturnal production was the major mechanism for aerosol formation
in Tumbarumba. |
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