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| Titel |
Seasonality of halogen deposition in polar snow and ice |
| VerfasserIn |
A. Spolaor, P. Vallelonga, J. Gabrieli, T. Martma, M. P. Björkman, E. Isaksson, G. Cozzi, C. Turetta, H. A. Kjær, M. A. J. Curran, A. D. Moy, A. Schönhardt, A.-M. Blechschmidt, J. P. Burrows, J. M. C. Plane, C. Barbante |
| 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 ; 14, no. 18 ; Nr. 14, no. 18 (2014-09-16), S.9613-9622 |
| Datensatznummer |
250119031
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| Publikation (Nr.) |
 copernicus.org/acp-14-9613-2014.pdf |
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| Zusammenfassung |
| The atmospheric chemistry of iodine and bromine in Polar regions is of
interest due to the key role of halogens in many atmospheric processes,
particularly tropospheric ozone destruction. Bromine is emitted from the
open ocean but is enriched above first-year sea ice during springtime
bromine explosion events, whereas iodine emission is attributed to
biological communities in the open ocean and hosted by sea ice. It has been
previously demonstrated that bromine and iodine are present in Antarctic ice
over glacial–interglacial cycles. Here we investigate seasonal variability
of bromine and iodine in polar snow and ice, to evaluate their emission,
transport and deposition in Antarctica and the Arctic and better understand
potential links to sea ice. We find that bromine and iodine concentrations
and Br enrichment (relative to sea salt content) in polar ice do vary
seasonally in Arctic snow and Antarctic ice. Although seasonal variability
in halogen emission sources is recorded by satellite-based observations of
tropospheric halogen concentrations, seasonal patterns observed in snowpack
are likely also influenced by photolysis-driven processes. Peaks of bromine
concentration and Br enrichment in Arctic snow and Antarctic ice occur in
spring and summer, when sunlight is present. A secondary bromine peak,
observed at the end of summer, is attributed to bromine deposition at the
end of the polar day. Iodine concentrations are largest in winter Antarctic
ice strata, contrary to contemporary observations of summer maxima in iodine
emissions. These findings support previous observations of iodine peaks in
winter snow strata attributed to the absence of sunlight-driven photolytic
re-mobilisation of iodine from surface snow. Further investigation is
required to confirm these proposed mechanisms explaining observations of
halogens in polar snow and ice, and to evaluate the extent to which halogens
may be applied as sea ice proxies. |
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