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| Titel |
Impact of gas-to-particle partitioning approaches on the simulated radiative effects of biogenic secondary organic aerosol |
| VerfasserIn |
C. E. Scott, D. V. Spracklen, J. R. Pierce, I. Riipinen, S. D. D'Andrea, A. Rap, K. S. Carslaw, P. M. Forster, P. Artaxo, M. Kulmala  , L. V. Rizzo, E. Swietlicki, G. W. Mann, K. J. Pringle |
| 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. 22 ; Nr. 15, no. 22 (2015-11-24), S.12989-13001 |
| Datensatznummer |
250120179
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| Publikation (Nr.) |
 copernicus.org/acp-15-12989-2015.pdf |
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| Zusammenfassung |
| The oxidation of biogenic volatile organic compounds
(BVOCs) gives a range of products, from semi-volatile to extremely
low-volatility compounds. To treat the interaction of these secondary organic
vapours with the particle phase, global aerosol microphysics models generally
use either a thermodynamic partitioning approach (assuming instant
equilibrium between semi-volatile oxidation products and the particle phase)
or a kinetic approach (accounting for the size dependence of condensation).
We show that model treatment of the partitioning of biogenic organic vapours
into the particle phase, and consequent distribution of material across the
size distribution, controls the magnitude of the first aerosol indirect
effect (AIE) due to biogenic secondary organic aerosol (SOA). With a kinetic
partitioning approach, SOA is distributed according to the existing
condensation sink, enhancing the growth of the smallest particles, i.e. those
in the nucleation mode. This process tends to increase cloud droplet number
concentrations in the presence of biogenic SOA. By contrast, an approach that
distributes SOA according to pre-existing organic mass restricts the growth
of the smallest particles, limiting the number that are able to form cloud
droplets. With an organically mediated new particle formation mechanism,
applying a mass-based rather than a kinetic approach to partitioning reduces
our calculated global mean AIE due to biogenic SOA by 24 %. Our results
suggest that the mechanisms driving organic partitioning need to be fully
understood in order to accurately describe the climatic effects of SOA. |
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