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| Titel |
Seasonal variability of atmospheric nitrogen oxides and non-methane hydrocarbons at the GEOSummit station, Greenland |
| VerfasserIn |
L. J. Kramer, D. Helmig, J. F. Burkhart, A. Stohl, S. Oltmans, R. E. Honrath |
| 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. 12 ; Nr. 15, no. 12 (2015-06-22), S.6827-6849 |
| Datensatznummer |
250119844
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| Publikation (Nr.) |
 copernicus.org/acp-15-6827-2015.pdf |
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| Zusammenfassung |
Measurements of atmospheric nitrogen oxides NOx
(NOx = NO + NO2), peroxyacetyl nitrate (PAN), NOy,
and non-methane hydrocarbons (NMHC) were taken at the Greenland Environmental Observatory at Summit (GEOSummit) station,
Greenland (72.34° N, 38.29° W; 3212 m a.s.l.), from
July 2008 to July 2010. The data set represents the first year-round
concurrent record of these compounds sampled at a high latitude Arctic site.
Here, the study focused on the seasonal variability of these important ozone
(O3) precursors in the Arctic troposphere and the impact from transported
anthropogenic and biomass burning emissions. Our analysis shows that PAN is
the dominant NOy species in all seasons at Summit, varying from 42 to
76 %; however, we find that odd NOy species (odd
NOy = NOy − PAN − NOx) contribute a large
amount to the total NOy speciation. We hypothesize that the source of this
odd NOy is most likely alkyl nitrates and nitric acid (HNO3) from
transported pollution, and photochemically produced species such as nitrous acid (HONO).
FLEXPART retroplume analyses and black carbon (BC) tracers for anthropogenic
and biomass burning (BB) emissions were used to identify periods when the
site was impacted by polluted air masses. Europe contributed the largest
source of anthropogenic emissions during the winter months (November–March)
with 56 % of the total anthropogenic BC tracer originating from Europe in
2008–2009 and 69 % in 2009–2010. The polluted plumes resulted in mean
enhancements above background levels up to 334, 295, 88, and
1119 pmol mol−1 for NOy, PAN, NOx, and ethane, respectively,
over the two winters. Enhancements in O3 precursors during the second
winter were typically higher, which may be attributed to the increase in
European polluted air masses transported to Summit in 2009–2010 compared to
2008–2009. O3 levels were highly variable within the sampled anthropogenic
plumes with mean ΔO3 levels ranging from −6.7 to
7.6 nmol mol−1 during the winter periods.
North America was the primary source of biomass burning emissions during the
summer; however, only 13 BB events were observed as the number of air masses
transported to Summit, with significant BB emissions, was low in general
during the measurement period. The BB plumes were typically very aged, with
median transport times to the site from the source region of 14 days. The
analyses of O3 and precursor levels during the BB events indicate
that some of the plumes sampled impacted the atmospheric chemistry at Summit,
with enhancements observed in all measured species. |
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