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| Titel |
Interactions between volatile organic compounds and reactive halogen in the tropical marine atmosphere using WRF-Chem |
| VerfasserIn |
Alba Badia, Claire E. Reeves, Alex Baker, Rainer Volkamer, Roland von Glasow |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250127984
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| Publikation (Nr.) |
 EGU/EGU2016-7918.pdf |
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| Zusammenfassung |
| Halogen species (chlorine, bromine and iodine) are known to play an important role in the
chemistry and oxidizing capacity of the troposphere, particularly in the marine boundary
layer (MBL). Reactive halogens cause ozone (O3) destruction, change the HOx and NOX
partitioning, affect the oxidation of volatile organic compounds (VOCs) and mercury, reduce
the lifetime of methane, and take part in new particle formation. Numerical models predicted
that reactive halogen compounds account for 30% of O3 destruction in the MBL and 5-20%
globally.
There are indications that the chemistry of reactive halogens and oxygenated VOCs
(OVOCs) in the tropics are inter-related. Moreover, the presence of aldehydes, such as
glyoxal (CHOCHO), has a potential impact on radical cycling and secondary organic aerosol
(SOA) formation in the MBL and free troposphere (FT). Model calculations suggest
aldehydes to be an important sink for bromine atoms and hence competition for their reaction
with O3 forming BrO and so illustrating a link between the cycles of halogens and OVOCs in
the marine atmosphere.
The main objective of this contribution is to investigate the atmospheric chemistry in the
tropical East Pacific with a focus on reactive halogens and OVOCs and their links using the
latest version of the Weather Research and Forecasting (WRF) model coupled with
Chemistry (WRF-Chem) and field data from the TORERO campaign. WRF-Chem is a highly
flexible community model for atmospheric research where aerosol-radiation-cloud feedback
processes are taken into account. Our current reaction mechanism in WRF-Chem is based on
the MOZART mechanism and has been extended to include bromine, chlorine and iodine
chemistry. The MOZART mechanism includes detailed gas-phase chemistry of CHOCHO
formation as well as state-of-the-science pathways to form SOA. Oceanic emissions of
aldehydes, including CHOCHO, and of organic halogens based on measurements from
the TORERO campaign have been added into the model. Sea surface emissions
of inorganic iodine are calculated using the parameterisation of Carpenter et al.,
2013.
Focusing on TORERO observations from the ships and a selected number of flights we
present an evaluation of the relevant tropospheric gas-phase chemistry (O3, H2O), inorganic
halogen species (BrO, IO), aldehydes (CH3CHO, CHOCHO) and Very Short Lived
Halocarbons (VSLH). |
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