Understanding mercury oxidation and air–snow exchange on the East Antarctic Plateau: a modeling study
Name
acp-18-15825-2018.pdf
Size
1.48 MB
Format
Adobe PDF
Checksum (MD5)
3cdf5094aec61d14c3797fc4b69ed03c
Author(s)
Gallée, Hubert
Sprovieri, Francesca
Pirrone, Nicola
Helmig, Detlev
Savarino, Joël
Magand, Olivier
Dommergue, Aurélien
Song, Shaojie
Angot, Helene Paule
Selin, Noelle E
Date Issued
November 2018
Journal
Atmospheric Chemistry and Physics
Publisher
Copernicus Publications
Citation
Song, Shaojie et al. “Understanding Mercury Oxidation and Air–snow Exchange on the East Antarctic Plateau: a Modeling Study.” Atmospheric Chemistry and Physics 18, 21 (November 2018): 15825–15840 © 2018 Author(s)
Version
Final published version
Abstract
Distinct diurnal and seasonal variations of mercury (Hg) have been observed in near-surface air at Concordia Station on the East Antarctic Plateau, but the processes controlling these characteristics are not well understood. Here, we use a box model to interpret the Hg0 (gaseous elemental mercury) measurements in thes year 2013. The model includes atmospheric Hg0 oxidation (by OH, O3, or bromine), surface snow HgII (oxidized mercury) reduction, and air-snow exchange, and is driven by meteorological fields from a regional climate model. The simulations suggest that a photochemically driven mercury diurnal cycle occurs at the air-snow interface in austral summer. The fast oxidation of Hg0 in summer may be provided by a two-step bromine-initiated scheme, which is favored by low temperature and high nitrogen oxides at Concordia. The summertime diurnal variations of Hg0 (peaking during daytime) may be confined within several tens of meters above the snow surface and affected by changing mixed layer depths. Snow re-emission of Hg0 is mainly driven by photoreduction of snow HgII in summer. Intermittent warming events and a hypothesized reduction of HgII occurring in snow in the dark may be important processes controlling the mercury variations in the non-summer period, although their relative importance is uncertain. The Br-initiated oxidation of Hg0 is expected to be slower at Summit Station in Greenland than at Concordia (due to their difference in temperature and levels of nitrogen oxides and ozone), which may contribute to the observed differences in the summertime diurnal variations of Hg0 between these two polar inland stations.
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
Massachusetts Institute of Technology. Institute for Data, Systems, and Society
Terms of Use
Creative Commons Attribution 4.0 International license
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.5194/acp-18-15825-2018
