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| Titel |
Importance of the organic aerosol fraction for modeling aerosol hygroscopic growth and activation: a case study in the Amazon Basin |
| VerfasserIn |
M. Mircea, M. C. Facchini, S. Decesari, F. Cavalli, L. Emblico, S. Fuzzi, A. Vestin, J. Rissler, E. Swietlicki, G. Frank, M. O. Andreae, W. Maenhaut, Y. Rudich, P. Artaxo |
| 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 ; 5, no. 11 ; Nr. 5, no. 11 (2005-11-17), S.3111-3126 |
| Datensatznummer |
250003153
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| Publikation (Nr.) |
 copernicus.org/acp-5-3111-2005.pdf |
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| Zusammenfassung |
| The aerosol in the Amazon basin is dominated throughout the year by organic
matter, for the most part soluble in water. In this modeling study, we show
how the knowledge of water-soluble organic compounds (WSOC) and the
associated physical and chemical properties (e.g. solubility, surface
tension, dissociation into ions) affect the hygroscopic growth and
activation of the aerosol in this area. The study is based on data obtained
during the SMOCC field experiment carried out in Rondônia, Brazil, over
a period encompassing the dry (biomass burning) season to the onset of the
wet season (September to mid-November, 2002). The comparison of predicted
and measured cloud condensation nuclei (CCN) number concentration shows that
the knowledge of aerosol WSOC composition in terms of classes of compounds
and of their relative molecular weights and acidic properties may be
sufficient to predict aerosol activation, without any information on
solubility. Conversely, the lack of knowledge on WSOC solubility leads to a
high overestimation of the observed diameter growth factors (DGF) by the
theory. Moreover, the aerosol water soluble inorganic species fail to predict both
DGFs and CCN number concentration. In fact, this study shows that a good reproduction
of the measured DGF and CCN concentration is obtained if the chemical composition of
aerosol, especially that of WSOC, is appropriately taken into account in
the calculations. New parameterizations for the computed CCN spectra are
also derived which take into account the variability caused by chemical
effects (surface tension, molecular composition, solubility, degree of
dissociation of WSOC). |
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