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| Titel |
Analysis of elevated springtime levels of Peroxyacetyl nitrate (PAN) at the high Alpine research sites Jungfraujoch and Zugspitze |
| VerfasserIn |
S. Pandey Deolal, S. Henne, L. Ries, S. Gilge, U. Weers, M. Steinbacher, J. Staehelin, T. Peter |
| 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 ; 14, no. 22 ; Nr. 14, no. 22 (2014-11-28), S.12553-12571 |
| Datensatznummer |
250119196
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| Publikation (Nr.) |
 copernicus.org/acp-14-12553-2014.pdf |
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| Zusammenfassung |
| The largest atmospheric peroxyacetyl nitrate (PAN) mole fractions at remote
surface sites in the Northern Hemisphere are commonly observed during the
months April and May. Different formation mechanisms for this seasonal
maximum have previously been suggested: hemispheric-scale production from
precursors accumulated during the winter months, increased springtime
transport from up-wind continents or increased regional-scale production in
the atmospheric boundary layer from recent emissions. The two high Alpine
research sites Jungfraujoch (Switzerland) and Zugspitze (Germany) exhibit a
distinct and consistent springtime PAN maximum. Since these sites
intermittently sample air masses of free-tropospheric and boundary layer
origin, they are ideally suited to identify the above-mentioned PAN
formation processes and attribute local observations to these. Here we
present a detailed analysis of PAN observations and meteorological
conditions during May 2008 when PAN levels were especially elevated at both
sites. The highest PAN concentrations were connected with anticyclonic
conditions, which persisted in May 2008 for about 10 days with north-easterly advection towards the sites. A backward dispersion model analysis
showed that elevated PAN concentrations were caused by the combination of
favourable photochemical production conditions and large precursor
concentrations in the European atmospheric boundary layer. The results
suggest that the largest PAN values in spring 2008 at both sites were
attributable to regional-scale photochemical production of PAN in the
(relatively cold) planetary boundary layer from European precursors, whereas
the contribution of inter-continental transport or free-tropospheric
build-up was of smaller importance for these sites. |
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