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| Titel |
Impact of the marine atmospheric boundary layer conditions on VSLS abundances in the eastern tropical and subtropical North Atlantic Ocean |
| VerfasserIn |
S. Fuhlbrügge, K. Krüger, B. Quack, E. Atlas, H. Hepach, F. Ziska |
| 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. 13 ; Nr. 13, no. 13 (2013-07-04), S.6345-6357 |
| Datensatznummer |
250018737
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| Publikation (Nr.) |
 copernicus.org/acp-13-6345-2013.pdf |
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| Zusammenfassung |
| During the DRIVE~(Diurnal and Regional Variability of Halogen Emissions)
ship campaign we investigated the variability of the halogenated very
short-lived substances (VSLS) bromoform (CHBr3), dibromomethane
(CH2Br2) and methyl iodide (CH3I) in the marine atmospheric
boundary layer in the eastern tropical and subtropical North Atlantic Ocean
during May/June 2010. The highest VSLS mixing ratios were found near the
Mauritanian coast and close to Lisbon (Portugal). With backward trajectories
we identified predominantly air masses from the open North Atlantic with
some coastal influence in the Mauritanian upwelling area, due to the
prevailing NW winds. The maximum VSLS mixing ratios above the Mauritanian
upwelling were 8.92 ppt for bromoform, 3.14 ppt for dibromomethane and 3.29 ppt
for methyl iodide, with an observed maximum range of the daily mean up
to 50% for bromoform, 26% for dibromomethane and 56% for methyl
iodide. The influence of various meteorological parameters – such as wind,
surface air pressure, surface air and surface water temperature, humidity
and marine atmospheric boundary layer (MABL) height – on VSLS concentrations
and fluxes was investigated. The strongest relationship was found between
the MABL height and bromoform, dibromomethane and methyl iodide abundances.
Lowest MABL heights above the Mauritanian upwelling area coincide with
highest VSLS mixing ratios and vice versa above the open ocean. Significant
high anti-correlations confirm this relationship for the whole cruise. We
conclude that especially above oceanic upwelling systems, in addition to
sea–air fluxes, MABL height variations can influence atmospheric VSLS mixing
ratios, occasionally leading to elevated atmospheric abundances. This may add
to the postulated missing VSLS sources in the Mauritanian upwelling region
(Quack et al., 2007). |
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