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| Titel |
Reactive nitrogen, ozone and ozone production in the Arctic troposphere and the impact of stratosphere-troposphere exchange |
| VerfasserIn |
Q. Liang, J. M. Rodriguez, A. R. Douglass, J. H. Crawford, J. R. Olson, E. Apel, H. Bian, D. R. Blake, W. Brune, M. Chin, P. R. Colarco, A. Silva, G. S. Diskin, B. N. Duncan, L. G. Huey, D. J. Knapp, D. D. Montzka, J. E. Nielsen, S. Pawson, D. D. Riemer, A. J. Weinheimer, A. Wisthaler |
| 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 ; 11, no. 24 ; Nr. 11, no. 24 (2011-12-21), S.13181-13199 |
| Datensatznummer |
250010297
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| Publikation (Nr.) |
 copernicus.org/acp-11-13181-2011.pdf |
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| Zusammenfassung |
| We use aircraft observations obtained during the Arctic Research of the
Composition of the Troposphere from Aircraft and Satellites (ARCTAS) mission
to examine the distributions and source attributions of O3 and NOy
in the Arctic and sub-Arctic region. Using a number of marker tracers, we
distinguish various air masses from the background troposphere and examine
their contributions to NOx, O3, and O3 production in the
Arctic troposphere. The background Arctic troposphere has a mean O3 of
~60 ppbv and NOx of ~25 pptv throughout spring and summer
with CO decreasing from ~145 ppbv in spring to ~100 ppbv in
summer. These observed mixing ratios are not notably different from the
values measured during the 1988 ABLE-3A and the 2002 TOPSE field campaigns
despite the significant changes in emissions and stratospheric ozone layer
in the past two decades that influence Arctic tropospheric composition. Air
masses associated with stratosphere-troposphere exchange are present
throughout the mid and upper troposphere during spring and summer. These air
masses, with mean O3 concentrations of 140–160 ppbv, are significant
direct sources of O3 in the Arctic troposphere. In addition, air of
stratospheric origin displays net O3 formation in the Arctic due to its
sustainable, high NOx (75 pptv in spring and 110 pptv in summer) and
NOy (~800 pptv in spring and ~1100 pptv in summer). The air
masses influenced by the stratosphere sampled during ARCTAS-B also show
conversion of HNO3 to PAN. This active production of PAN is the result
of increased degradation of ethane in the stratosphere-troposphere mixed air
mass to form CH3CHO, followed by subsequent formation of PAN under high
NOx conditions. These findings imply that an adequate representation of
stratospheric NOy input, in addition to stratospheric O3 influx,
is essential to accurately simulate tropospheric Arctic O3, NOx
and PAN in chemistry transport models. Plumes influenced by recent
anthropogenic and biomass burning emissions observed during ARCTAS show
highly elevated levels of hydrocarbons and NOy (mostly in the form of
NOx and PAN), but do not contain O3 higher than that in the Arctic
tropospheric background except some aged biomass burning plumes sampled
during spring. Convection and/or lightning influences are negligible sources
of O3 in the Arctic troposphere but can have significant impacts in the
upper troposphere in the continental sub-Arctic during summer. |
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