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| Titel |
Pollution transport from North America to Greenland during summer 2008 |
| VerfasserIn |
J. L. Thomas, J.-C. Raut, K. S. Law, L. Marelle, G. Ancellet, F. Ravetta, J. D. Fast, G. Pfister, L. K. Emmons, G. S. Diskin, A. Weinheimer, A. Roiger, H. Schlager |
| 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 ; 13, no. 7 ; Nr. 13, no. 7 (2013-04-10), S.3825-3848 |
| Datensatznummer |
250018582
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| Publikation (Nr.) |
 copernicus.org/acp-13-3825-2013.pdf |
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| Zusammenfassung |
| Ozone pollution transported to the Arctic is a significant concern
because of the rapid, enhanced warming in high northern latitudes,
which is caused, in part, by short-lived climate forcers, such as
ozone. Long-range transport of pollution contributes to background
and episodic ozone levels in the Arctic. However, the extent to
which plumes are photochemically active during transport,
particularly during the summer, is still uncertain. In this study,
regional chemical transport model simulations are used to examine
photochemical production of ozone in air masses originating from
boreal fire and anthropogenic emissions over North America and
during their transport toward the Arctic during early July
2008. Model results are evaluated using POLARCAT aircraft data
collected over boreal fire source regions in Canada (ARCTAS-B) and
several days downwind over Greenland (POLARCAT-France and
POLARCAT-GRACE). Model results are generally
in good agreement with the observations, except for certain trace
gas species over boreal fire regions, in some cases indicating that
the fire emissions are too low. Anthropogenic and biomass burning
pollution (BB) from North America was rapidly uplifted during
transport east and north to Greenland where pollution plumes were
observed in the mid- and upper troposphere during POLARCAT. A model
sensitivity study shows that CO levels are in better agreement with
POLARCAT measurements (fresh and aged fire plumes) upon doubling CO
emissions from fires. Analysis of model results, using
ΔO3/ΔCO enhancement ratios, shows
that pollution plumes formed ozone during transport towards the
Arctic. Fresh anthropogenic plumes have average
ΔO3/ΔCO enhancement ratios of 0.63
increasing to 0.92 for aged anthropogenic plumes, indicating
additional ozone production during aging. Fresh fire plumes are only
slightly enhanced in ozone
(ΔO3/ΔCO=0.08), but form ozone
downwind with ΔO3/ΔCO of 0.49 for
aged BB plumes (model-based run). We estimate that aged anthropogenic and BB pollution
together made an important contribution to ozone levels with an
average contribution for latitudes >55° N of up to
6.5 ppbv (18%) from anthropogenic pollution and 3 ppbv
(5.2%) from fire pollution in the model domain in summer 2008. |
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