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Titel |
Partitioning of reactive nitrogen (NOy) and dependence on meteorological conditions in the lower free troposphere |
VerfasserIn |
C. Zellweger, J. Forrer, P. Hofer, S. Nyeki, B. Schwarzenbach, E. Weingärtner, M. Ammann, U. Baltensperger |
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 ; 3, no. 3 ; Nr. 3, no. 3 (2003-06-19), S.779-796 |
Datensatznummer |
250001047
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Publikation (Nr.) |
copernicus.org/acp-3-779-2003.pdf |
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Zusammenfassung |
Results of continuous nitrogen oxide (NO), nitrogen dioxide
(NO2), peroxyacetyl nitrate (PAN) and total reactive nitrogen (NOy) measurements along with seasonal field campaigns
of nitric acid (HNO3) and particulate nitrate (NO3-)
measurements are presented for a two-year period at the high-alpine research station Jungfraujoch
(JFJ), 3580 m asl. The NOy mixing ratio and partitioning is shown to strongly
depend on meteorological conditions. Knowledge of these meteorological transport processes allows discrimination between
undisturbed (i.e. clean) and disturbed (i.e. influenced by regional pollution sources) free tropospheric (FT) conditions at
the JFJ. Median NOy concentrations during undisturbed FT periods ranged from
350 pptv (winter, December to February) to 581 pptv (spring, March to May). PAN was found to be the
dominant NOy species during spring and summer, whereas NO2 was most abundant during autumn and winter. Particulate
nitrate was found to contribute significantly to total NOy during thermally induced vertical transport.
Föhn events, synoptical lifting (e.g. fronts) and thermally induced vertical
transport resulted in mixing ratios up to 10 times higher at the JFJ compared to undisturbed FT conditions. Furthermore this
meteorological variability of the NOy concentration and partitioning often dominated the seasonal variability. As a
consequence the use of filters at the JFJ (and other mountainous sites) is crucial for the interpretation of data from such
measurement sites. This study presents a further development of meteorological filters for the high-alpine site
Jungfraujoch, which also could be modified and adapted to other mountainous
measurement sites. |
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