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| Titel |
OH and HO2 chemistry during NAMBLEX: roles of oxygenates, halogen oxides and heterogeneous uptake |
| VerfasserIn |
R. Sommariva, W. J. Bloss, N. Brough, N. Carslaw, M. Flynn, A.-L. Haggerstone, D. E. Heard, J. R. Hopkins, J. D. Lee, A. C. Lewis, G. McFiggans, P. S. Monks, S. A. Penkett, M. J. Pilling, J. M. C. Plane, K. A. Read, A. Saiz-Lopez, A. R. Rickard, P. I. Williams |
| 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 ; 6, no. 4 ; Nr. 6, no. 4 (2006-04-05), S.1135-1153 |
| Datensatznummer |
250003634
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| Publikation (Nr.) |
 copernicus.org/acp-6-1135-2006.pdf |
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| Zusammenfassung |
| Several zero-dimensional box-models with different levels of
chemical complexity, based on the Master Chemical Mechanism (MCM),
have been used to study the chemistry of OH and HO2
in a coastal environment in the Northern Hemisphere. The models
were constrained to and compared with measurements made during the
NAMBLEX campaign (Mace Head, Ireland) in summer 2002.
The base models, which were constrained to measured CO,
CH4 and NMHCs, were able to reproduce [OH] within
25%, but overestimated [HO2] by about a factor of 2.
Agreement was improved when the models were constrained to
oxygenated compounds (acetaldehyde, methanol and acetone),
highlighting their importance for the radical budget. When the
models were constrained to measured halogen monoxides (IO,
BrO) and used a more detailed, measurements-based,
treatment to describe the heterogeneous uptake, modelled
[OH] increased by up to 15% and [HO2] decreased by
up to 30%. The actual impact of halogen monoxides on the modelled
concentrations of HOx was dependant on the uptake
coefficients used for HOI, HOBr and HO2.
Better agreement, within the combined uncertainties of the
measurements and of the model, was achieved when using high uptake
coefficients for HO2 and HOI
(γHO2=1, γHOI=0.6).
A rate of production and destruction analysis of the models
allowed a detailed study of OH and HO2 chemistry
under the conditions encountered during NAMBLEX, showing the
importance of oxygenates and of XO (where X=I, Br) as co-reactants for OH and
HO2
and of HOX photolysis as a source for OH. |
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