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| Titel |
Radicals in the marine boundary layer during NEAQS 2004: a model study of day-time and night-time sources and sinks |
| VerfasserIn |
R. Sommariva, H. D. Osthoff, S. S. Brown, T. S. Bates, T. Baynard, D. Coffman, J. A. Gouw, P. D. Goldan, W. C. Kuster, B. M. Lerner, H. Stärk, C. Warneke, E. J. Williams, F. C. Fehsenfeld, A. R. Ravishankara, M. Trainer |
| 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 ; 9, no. 9 ; Nr. 9, no. 9 (2009-05-13), S.3075-3093 |
| Datensatznummer |
250007274
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| Publikation (Nr.) |
 copernicus.org/acp-9-3075-2009.pdf |
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| Zusammenfassung |
This paper describes a modelling study of several HOx and
NOx species (OH, HO2, organic peroxy radicals, NO3
and N2O5) in the marine boundary layer. A model based upon the
Master Chemical Mechanism (MCM) was constrained to observations of
chemical and physical parameters made onboard the NOAA ship R/V
Brown as part of the New England Air Quality Study (NEAQS)
in the summer of 2004. The model was used to calculate [OH] and to
determine the composition of the peroxy radical pool. Modelled
[NO3] and [N2O5] were compared to in-situ measurements by
Cavity Ring-Down Spectroscopy. The comparison showed that the model
generally overestimated the measurements by 30–50%, on average.
The model results were analyzed with respect to several chemical and
physical parameters, including uptake of NO3 and N2O5 on
fog droplets and on aerosol, dry deposition of NO3 and
N2O5, gas-phase hydrolysis of N2O5 and reactions of
NO3 with NMHCs and peroxy radicals. The results suggest that fog,
when present, is an important sink for N2O5 via rapid
heterogeneous uptake. The comparison between the model and the
measurements were consistent with values of the heterogeneous uptake
coefficient of N2O5
(γN2O5)>1×10−2, independent of
aerosol composition in this marine environment. The analysis of the
different loss processes of the nitrate radical showed the important
role of the organic peroxy radicals, which accounted for a
significant fraction (median: 15%) of NO3 gas-phase removal,
particularly in the presence of high concentrations of dimethyl
sulphide (DMS). |
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