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| Titel |
Long range transport of mercury to the Arctic and across Canada |
| VerfasserIn |
D. Durnford, A. Dastoor, D. Figueras-Nieto, A. Ryjkov |
| 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. 13 ; Nr. 10, no. 13 (2010-07-06), S.6063-6086 |
| Datensatznummer |
250008602
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| Publikation (Nr.) |
 copernicus.org/acp-10-6063-2010.pdf |
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| Zusammenfassung |
This study is the most extensive study to date on the transport of mercury
to the Arctic. Moreover, it is the first such study to use a fully-coupled,
online chemical transport model, Environment Canada's Global/Regional
Atmospheric Heavy Metals model (GRAHM), where the meteorology and mercury
processes are fully integrated. It is also the only study to date on the
transport of mercury across Canada. We estimated source attribution from
Asia, North America, Russia and Europe at six arctic verification stations,
as well as three subarctic and eight midlatitude Canadian stations.
We have found that Asia, despite having transport efficiencies that were
almost always lower than those of North America and often lower than those
of Russia, was the dominant source of gaseous atmospheric mercury at all
verification stations: it contributed the most mercury (29–37% at all
stations, seasons and levels considered), its concentrations frequently
explained nearly 100% of the variability in the concentrations produced
by the simulation performed with full global emissions, particularly in the
absence of local sources, and it generated the most long range transport
(LRT) events, causing 43%, 67% and 75% of the events at the arctic,
subarctic and midlatitude stations, respectively. For the Arctic, Russian
transport efficiencies tended to be the strongest, as expected, while
European and Asian efficiencies were lower and higher, respectively, than
those found in the literature. This disagreement is likely produced by
mercury's long lifetime relative to that of other pollutants. The accepted
springtime preference for the trans-Pacific transport of Asian pollution was
evident only in the midlatitude group of stations, being masked in the
arctic and subarctic groups by the occurrence of atmospheric mercury
depletion events. Some neighbouring arctic stations recorded dissimilar
numbers of LRT events; despite their proximity, the behaviour of mercury at
these stations was governed by different dynamics and transport pathways.
The column burden of GEM in the lowest 5 km of the Northern Hemisphere was
largest in summer from Asia, North America and Russia, but in winter from
Europe. In the vertical, transport of mercury from all source regions
occurred principally in the mid-troposphere. |
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