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| Titel |
Combined effects of surface conditions, boundary layer dynamics and chemistry on diurnal SOA evolution |
| VerfasserIn |
R. H. H. Janssen, J. Vilà-Guerau de Arellano, L. N. Ganzeveld, P. Kabat, J. L. Jimenez, D. K. Farmer, C. C. Heerwaarden, I. Mammarella |
| 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 ; 12, no. 15 ; Nr. 12, no. 15 (2012-08-01), S.6827-6843 |
| Datensatznummer |
250011358
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| Publikation (Nr.) |
 copernicus.org/acp-12-6827-2012.pdf |
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| Zusammenfassung |
| We study the combined effects of land surface conditions, atmospheric
boundary layer dynamics and chemistry on the diurnal evolution of biogenic
secondary organic aerosol in the atmospheric boundary layer, using a model
that contains the essentials of all these components. First, we evaluate the
model for a case study in Hyytiälä, Finland, and find that it is able
to satisfactorily reproduce the observed dynamics and gas-phase chemistry. We
show that the exchange of organic aerosol between the free troposphere and
the boundary layer (entrainment) must be taken into account in order to
explain the observed diurnal cycle in organic aerosol (OA) concentration. An
examination of the budgets of organic aerosol and terpene concentrations show
that the former is dominated by entrainment, while the latter is mainly
driven by emission and chemical transformation. We systematically investigate
the role of the land surface, which governs both the surface energy balance
partitioning and terpene emissions, and the large-scale atmospheric process
of vertical subsidence. Entrainment is especially important for the dilution
of organic aerosol concentrations under conditions of dry soils and low
terpene emissions. Subsidence suppresses boundary layer growth while
enhancing entrainment. Therefore, it influences the relationship between
organic aerosol and terpene concentrations. Our findings indicate that the
diurnal evolution of secondary organic aerosols (SOA) in the boundary layer is the result of coupled
effects of the land surface, dynamics of the atmospheric boundary layer,
chemistry, and free troposphere conditions. This has potentially some
consequences for the design of both field campaigns and large-scale modeling
studies. |
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