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| Titel |
Ion-mediated nucleation as an important global source of tropospheric aerosols |
| VerfasserIn |
F. Yu, Z. Wang, G. Luo, R. Turco |
| 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. 9 ; Nr. 8, no. 9 (2008-05-15), S.2537-2554 |
| Datensatznummer |
250006107
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| Publikation (Nr.) |
 copernicus.org/acp-8-2537-2008.pdf |
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| Zusammenfassung |
| Aerosol nucleation events have been observed at a variety
of locations worldwide, and may have significant climatic and health
implications. While ions have long been suggested as favorable nucleation
embryos, their significance as a global source of particles has remained
uncertain. Here, an ion-mediated nucleation (IMN) mechanism, which
incorporates new thermodynamic data and physical algorithms, has been
integrated into a global chemical transport model (GEOS-Chem) to study
ion-mediated particle formation in the global troposphere. The simulated
annual mean results have been compared to a comprehensive set of data
relevant to particle nucleation around the globe. We show that predicted
annual spatial patterns of particle formation agree reasonably well with
land-, ship-, and aircraft-based observations. Our simulations show that,
globally, IMN in the boundary layer is largely confined to two broad
latitude belts: one in the northern hemisphere (~20° N–70° N),
and one in the southern hemisphere (~30° S–90° S). In the
middle latitude boundary layer over continents, the annual mean IMN rates
are generally above 104 cm−3day−1, with some hot spots
reaching 105 cm−3day−1. The zonally-averaged vertical
distribution of IMN rates indicates that IMN is significant in the tropical
upper troposphere, the entire middle latitude troposphere, and over
Antarctica. Comparing the relative strengths of particle sources due to IMN
and due to primary particle emissions demonstrates that IMN is significant
on a global scale. Further research is needed to reduce modeling
uncertainties and to understand the ultimate contribution of freshly
nucleated particles to the abundance of cloud condensation nuclei. |
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