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| Titel |
Contributions from DMS and ship emissions to CCN observed over the summertime North Pacific |
| VerfasserIn |
L. Langley, W. R. Leaitch, U. Lohmann, N. C. Shantz, D. R. Worsnop |
| 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. 3 ; Nr. 10, no. 3 (2010-02-05), S.1287-1314 |
| Datensatznummer |
250008044
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| Publikation (Nr.) |
 copernicus.org/acp-10-1287-2010.pdf |
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| Zusammenfassung |
| Measurements of cloud condensation nuclei (CCN) made over the North Pacific
Ocean in July 2002 are analysed with concurrent measurements of aerosol
number, mass and composition. Overall the CCN are controlled by the
sulphate, including one case that suggests particle nucleation and growth
resulting from dimethyl sulphide oxidation that enhanced CCN concentrations.
Hourly CCN concentrations are correlated with concentrations of sulphate
plus methanesulphonic acid (MSA) over the entire study period (r2=0.43
and 0.52 for supersaturations of 0.34% and 0.19%, respectively), and
are not well correlated with other organics (r2<0.2). One case study
reveals elevated mass and number concentrations of ultrafine and fine
organic particles due to regional ship emissions, identified through
quadrupole aerosol mass spectrometer (Q-AMS) measurements, during which
organic mass concentrations are correlated with CCN values (r2=0.39
and 0.46 for supersaturations of 0.19% and 0.34%, respectively). The
evolution of the time series and mass distributions of organics, sulphate
and MSA over this timeframe indicate that the regional distribution of
small, diffuse ship-sourced organic particles act as condensation sites for
sulphur species, resulting in a subsequent increase in number concentrations
of CCN. We conclude that, where present, direct emissions of anthropogenic organic particles
may exert a strong control on marine CCN concentrations once diffused into
the marine atmosphere, by acting as condensation sites for biogenic and
anthropogenic sulphur species. |
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