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| Titel |
Sources of atmospheric mercury in the tropics: continuous observations at a coastal site in Suriname |
| VerfasserIn |
D. Müller, D. Wip, T. Warneke, C. D. Holmes, A. Dastoor, J. Notholt |
| 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 ; 12, no. 16 ; Nr. 12, no. 16 (2012-08-16), S.7391-7397 |
| Datensatznummer |
250011391
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| Publikation (Nr.) |
 copernicus.org/acp-12-7391-2012.pdf |
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| Zusammenfassung |
| Mercury measurements at a coastal site in Nieuw Nickerie (5°56' N,
56°59' W), Suriname, provide the only continuous records of atmospheric
mercury in the tropics. Here we evaluate observations of total gaseous
mercury (TGM) during 2007. Nieuw Nickerie typically samples marine air from
the Atlantic Ocean, with occasional influence from continental South
America. Over the year, average concentrations are 1.40 ng m−3. As the
intertropical convergence zone passes over Suriname twice each year, the
site samples both northern and southern hemispheric air masses. We use back
trajectories to classify each measurement by hemisphere, as well as
continental or ocean. For air passing over ocean before sampling, TGM
concentrations are 10% higher in air coming from the Northern Hemisphere
(1.45 ng m−3) than from the Southern Hemisphere (1.32 ng m−3). Air
from the South American continent also carries higher TGM (1.43 ng m−3)
than air from the South Atlantic Ocean, with most of these trajectories
occurring in August and September. Biomass burning in Brazil peaks in the
same months and likely contributes significantly to elevated concentrations
seen in Nickerie. We also compare the observed seasonal cycle to two
atmospheric mercury chemistry and transport models (GRAHM and GEOS-Chem).
Both models simulate transition between northern and southern hemispheric
air, thus capturing the seasonal cycle; however the models overestimate the
TGM concentrations during months when Nickerie samples Northern Hemisphere
air. It is difficult to determine whether the models' sources or sinks in
the Northern Hemisphere tropics are responsible. |
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