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Titel |
Cloud condensation nuclei activity at Jeju Island, Korea in spring 2005 |
VerfasserIn |
M. Kuwata, Y. Kondo, Y. Miyazaki, Y. Komazaki, J. H. Kim, S. S. Yum, H. Tanimoto, H. Matsueda |
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. 11 ; Nr. 8, no. 11 (2008-06-11), S.2933-2948 |
Datensatznummer |
250006183
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Publikation (Nr.) |
copernicus.org/acp-8-2933-2008.pdf |
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Zusammenfassung |
We measured the number concentrations of cloud condensation nuclei (CCN) and
the size distributions of CCN/CN (CN: condensation nuclei) ratios at
supersaturations (SSs) of 0.097, 0.27, 0.58, and 0.97% at Jeju Island,
Korea during March-April 2005. We made simultaneous measurements of aerosol
inorganic ions, water-soluble organic carbon (WSOC), organic carbon (OC), and
elemental carbon (EC) in PM2.5. The CCN/CN ratios increased with increasing
particle diameter, and the diameter at CCN/CN=0.5 was defined as
D50. D50 represents the activation dry diameter of atmospheric
particles. The average D50 at SS=0.097% and 0.97% was 136±17 nm
and 31±3 nm, respectively. The temporal variation of D50
at SS=0.097% was correlated with the mass fraction of water-soluble
components (inorganic ions + WSOC), indicating that the temporal variation of
CCN activity was mainly controlled by changes in the water-soluble components
fraction. The critical dry diameter (Dcrit), which is the threshold dry
diameter for CCN activation, was calculated from the observed aerosol
chemical compositions by Köhler theory for comparison with D50. The
D50 at SS=0.097% was correlated (r2=0.48) with calculated
Dcrit, although Dcrit was larger than D50 by 20–29% on
average. The systematic difference between D50 and Dcrit could be
caused by the size dependence of the aerosol chemical compositions or surface
tension lowering caused by the mixing of water-soluble organic compounds.
This difference corresponds to a 27±14% uncertainty in the CCN
number concentration estimated from the observed particle number size
distribution. |
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