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| Titel |
Size-resolved cloud condensation nuclei concentration measurements in the Arctic: two case studies from the summer of 2008 |
| VerfasserIn |
J. Zábori, N. Rastak, Y. J. Yoon, I. Riipinen, J. Ström |
| 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 ; 15, no. 23 ; Nr. 15, no. 23 (2015-12-15), S.13803-13817 |
| Datensatznummer |
250120226
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| Publikation (Nr.) |
 copernicus.org/acp-15-13803-2015.pdf |
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| Zusammenfassung |
| The Arctic is one of the most vulnerable regions affected by climate change.
Extensive measurement data are needed to understand the atmospheric
processes governing this vulnerability. Among these, data describing cloud
formation potential are of particular interest, since the indirect effect of
aerosols on the climate system is still poorly understood. In this paper we
present, for the first time, size-resolved cloud condensation nuclei (CCN)
data obtained in the Arctic. The measurements were conducted during two
periods in the summer of 2008: one in June and one in August, at the
Zeppelin research station (78°54´ N, 11°53´ E) in
Svalbard. Trajectory analysis indicates that during the measurement period
in June 2008, air masses predominantly originated from the Arctic, whereas
the measurements from August 2008 were influenced by mid-latitude air masses.
CCN supersaturation (SS) spectra obtained on the 27 June, before
size-resolved measurements were begun, and spectra from the 21 and 24 August, conducted before and after the measurement period, revealed
similarities between the 2 months. From the ratio between CCN
concentration and the total particle number concentration (CN) as a function
of dry particle diameter (Dp) at a SS of 0.4 %, the activation
diameter (D50), corresponding to CCN / CN = 0.50, was estimated.
D50 was found to be 60 and 67 nm for the examined periods in June and
August 2008, respectively. Corresponding D50 hygroscopicity parameter
(κ) values were estimated to be 0.4 and 0.3 for June and August 2008, respectively. These values can be compared to hygroscopicity values
estimated from bulk chemical composition, where κ was calculated to
be 0.5 for both June and August 2008. While the agreement between the 2
months is reasonable, the difference in κ between the different
methods indicates a size dependence in the particle composition, which is
likely explained by a higher fraction of inorganics in the bulk aerosol
samples. |
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