Dynamic recycling of gaseous elemental mercury in the boundary layer of the Antarctic Plateau 1UJF – Grenoble 1/CNRS, Laboratoire de Glaciologie et Géophysique de l'Environnement (LGGE) UMR5183, Grenoble, 38041, France
21 Nov 2012
2Institute for Atmospheric Science and Climate, National Research Council, Bologna, Italy
Received: 21 June 2012 – Published in Atmos. Chem. Phys. Discuss.: 23 July 2012 Abstract. Gaseous elemental mercury (Hg0) was investigated in the troposphere and in
the interstitial air extracted from the snow at Dome Concordia station (alt.
3320 m) on the Antarctic Plateau during January 2009. Measurements and
modeling studies showed evidence of a very dynamic and daily cycling of
Hg0 inside the mixing layer with a range of values from 0.2 ng m−3 up
to 2.3 ng m−3. During low solar irradiation periods, fast Hg0
oxidation processes in a confined layer were suspected. Unexpectedly high
Hg0 concentrations for such a remote place were measured under higher
solar irradiation due to snow photochemistry. We suggest that a daily
cycling of reemission/oxidation occurs during summer within the mixing layer
at Dome Concordia.
Hg0 concentrations showed a negative correlation with ozone mixing ratios,
which contrasts with atmospheric mercury depletion events observed during
the Arctic spring. Unlike previous Antarctic studies, we think that
atmospheric Hg0 removal may not be the result of advection processes. The
daily and dramatic Hg0 losses could be a consequence of surface or snow
induced oxidation pathways. It remains however unclear whether halogens are
involved. The cycling of other oxidants should be investigated together with
Hg species in order to clarify the complex reactivity on the Antarctic
Revised: 07 November 2012 – Accepted: 08 November 2012 – Published: 21 November 2012
Citation: Dommergue, A., Barret, M., Courteaud, J., Cristofanelli, P., Ferrari, C. P., and Gallée, H.: Dynamic recycling of gaseous elemental mercury in the boundary layer of the Antarctic Plateau, Atmos. Chem. Phys., 12, 11027-11036, doi:10.5194/acp-12-11027-2012, 2012.