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Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
doi:10.5194/acp-2017-305
© Author(s) 2017. This work is distributed
under the Creative Commons Attribution 3.0 License.
Research article
11 Apr 2017
Review status
This discussion paper is under review for the journal Atmospheric Chemistry and Physics (ACP).
Year-round record of bulk and size-segregated aerosol composition in central Antarctica (Concordia site) Part 2: Biogenic sulfur (sulfate and methanesulfonate) aerosol
Michel Legrand1,2, Susanne Preunkert1,2, Rolf Weller3, Lars Zipf4, Christoph Elsässer4, Silke Merchel5, Georg Rugel5, and Dietmar Wagenbach4,† 1Université Grenoble Alpes, Laboratoire de Glaciologie et Géophysique de l’Environnement (LGGE), Grenoble, 38402, France
2CNRS, Laboratoire de Glaciologie et Géophysique de l’Environnement (LGGE), Grenoble, 38402, France
3Alfred Wegener Institut für Polar und Meeresforschung, Bremerhaven, 27570, Germany
4Institut für Umweltphysik, University of Heidelberg, Heidelberg, 69120, Germany
5Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden, 01328, Germany
deceased, December 2014
Abstract. Multiple year-round (2006–2015) records of the bulk and size-segregated composition of aerosol were obtained at the inland site of Concordia located in East Antarctica. The well-marked maximum of non-sea-salt sulfate (nssSO4) in January (84 ± 25 ng m−3 against 4.4 ± 2.3 ng m−3 in July) is consistent with observations made at the coast (280 ± 78 ng m−3 in January against 16 ± 9 ng m−3 in July at Dumont d’Urville, for instance). In contrast, the well-marked maximum of MSA at the coast in January (60 ± 23 ng m−3 at Dumont d’Urville) is not observed at Concordia (4.6 ± 2.4 ng m−3 in January). Instead, the MSA level at Concordia peaks in October (5.6 ± 1.9 ng m−3) and March (13.2 ± 6.1 ng m−3). As a result, a surprisingly low MSA to nssSO4 ratio (RMSA) is observed at Concordia in mid-summer (0.05 ± 0.02 in January against 0.25 ± 0.09 in March). We find that the low value of RMSA in mid-summer at Concordia is mainly driven by a drop of MSA levels that takes place in submicron aerosol (0.3 µm diameter). The drop of MSA coincides with periods of high photochemical activity as indicated by high ozone levels, strongly suggesting the occurrence of an efficient chemical destruction of MSA over the Antarctic plateau in mid-summer. The relationship between MSA and nssSO4 levels is examined separately for each season and indicates that concentration of non-biogenic sulfate over the Antarctic plateau does not exceed 1 ng m−3 in fall and winter and remains below 5 ng m−3 in spring. This weak non-biogenic sulfate level is discussed in the light of radionuclides (210Pb, 10Be, and 7Be) also measured on bulk aerosol samples collected at Concordia. The findings highlight the complexity in using MSA in deep ice cores extracted from inland Antarctica as a proxy of past DMS emissions from the southern ocean.

Citation: Legrand, M., Preunkert, S., Weller, R., Zipf, L., Elsässer, C., Merchel, S., Rugel, G., and Wagenbach, D.: Year-round record of bulk and size-segregated aerosol composition in central Antarctica (Concordia site) Part 2: Biogenic sulfur (sulfate and methanesulfonate) aerosol, Atmos. Chem. Phys. Discuss., doi:10.5194/acp-2017-305, in review, 2017.
Michel Legrand et al.
Michel Legrand et al.
Michel Legrand et al.

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Short summary
Levels of MSA and sulfate at inland Antarctica are documented from multiple year-round records of bulk and size-segregated aerosol samplings. A striking difference in the seasonality of sulfur aerosol composition, characterized by a MSA to nssSO4 ratio reaching a minimum in summer over the Antarctic plateau (0.05) and a maximum at the coast (up to 0.40), is clearly established. An efficient chemical destruction of MSA is suggested to take place over the Antarctic plateau in summer.
Levels of MSA and sulfate at inland Antarctica are documented from multiple year-round records...
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