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| Titel |
A 15 year record of high-frequency, in situ measurements of hydrogen at Mace Head, Ireland |
| VerfasserIn |
A. Grant, C. S. Witham, P. G. Simmonds, A. J. Manning, S. O'Doherty |
| 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 ; 10, no. 3 ; Nr. 10, no. 3 (2010-02-03), S.1203-1214 |
| Datensatznummer |
250008039
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| Publikation (Nr.) |
 copernicus.org/acp-10-1203-2010.pdf |
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| Zusammenfassung |
| Continuous high-frequency measurements of atmospheric molecular hydrogen have
been made at Mace Head atmospheric research station on the west coast of
Ireland from March 1994 to December 2008. The presented data provides
information on long term trends and seasonal cycles of hydrogen in background
northern hemispheric air. Individual measurements have been sorted using a
Lagrangian dispersion model to separate clean background air from regionally
polluted European air masses and those transported from southerly latitudes.
No significant trend was observed in background northern hemispheric air over
the 15 year record, elevations in yearly means were accounted for from large
scale biomass burning events. Seasonal cycles show the expected pattern with
maxima in spring and minima in late autumn. The mean hydrogen mole fraction
in baseline northern hemispheric air was found to be 500.1 ppb. Air
transported from southerly latitudes showed an elevation from baseline mean
of 11.0 ppb, reflecting both the latitudinal gradient of hydrogen, with
higher concentrations in the Southern Hemisphere, and the photochemical
source of hydrogen from low northern latitudes. European polluted air masses
arriving at Mace Head showed mean elevation of 5.3 ppb from baseline air
masses, reflecting hydrogen's source from primary emissions like fossil fuel
combustion. Forward modelling of transport of hydrogen to Mace Head suggests
that the ratio of hydrogen to carbon monoxide in primary emissions is
considerably less in non-traffic sources than traffic sources. |
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