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| Titel |
The NOx dependence of bromine chemistry in the Arctic atmospheric boundary layer |
| VerfasserIn |
K. D. Custard, C. R. Thompson, K. A. Pratt, P. B. Shepson, J. Liao, L. G. Huey, J. J. Orlando, A. J. Weinheimer, E. Apel, S. R. Hall, F. Flocke, L. Mauldin, R. S. Hornbrook, D. Pöhler, S. General, J. Zielcke, W. R. Simpson, U. Platt, A. Fried, P. Weibring, B. C. Sive, K. Ullmann, C. Cantrell, D. J. Knapp, D. D. Montzka |
| 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 ; 15, no. 18 ; Nr. 15, no. 18 (2015-09-29), S.10799-10809 |
| Datensatznummer |
250120061
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| Publikation (Nr.) |
 copernicus.org/acp-15-10799-2015.pdf |
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| Zusammenfassung |
| Arctic boundary layer nitrogen oxides (NOx = NO2 + NO) are
naturally produced in and released from the sunlit snowpack and range
between 10 to 100 pptv in the remote background surface layer air. These
nitrogen oxides have significant effects on the partitioning and cycling of
reactive radicals such as halogens and HOx (OH + HO2). However,
little is known about the impacts of local anthropogenic NOx emission
sources on gas-phase halogen chemistry in the Arctic, and this is important
because these emissions can induce large variability in ambient NOx and
thus local chemistry. In this study, a zero-dimensional photochemical
kinetics model was used to investigate the influence of NOx on the
unique springtime halogen and HOx chemistry in the Arctic. Trace gas
measurements obtained during the 2009 OASIS (Ocean – Atmosphere – Sea
Ice – Snowpack) field campaign at Barrow, AK were used to constrain many model
inputs. We find that elevated NOx significantly impedes gas-phase
halogen radical-based depletion of ozone, through the production of a
variety of reservoir species, including HNO3, HO2NO2,
peroxyacetyl nitrate (PAN), BrNO2, ClNO2 and reductions in BrO and
HOBr. The effective removal of BrO by anthropogenic NOx was directly
observed from measurements conducted near Prudhoe Bay, AK during the 2012
Bromine, Ozone, and Mercury Experiment (BROMEX). Thus, while changes in
snow-covered sea ice attributable to climate change may alter the
availability of molecular halogens for ozone and Hg depletion, predicting
the impact of climate change on polar atmospheric chemistry is complex and
must take into account the simultaneous impact of changes in the
distribution and intensity of anthropogenic combustion sources. This is
especially true for the Arctic, where NOx emissions are expected to
increase because of increasing oil and gas extraction and shipping
activities. |
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