Monitoring of gaseous elemental mercury in central Antarctica at Dome Concordia.

Within the framework of the Global Mercury Observation System (GMOS), we are monitoring gaseous elemental mercury (Hg(0)) at the Dome Concordia Station to improve our understanding of atmospheric Hg in the Antarctic atmosphere. This French-Italian facility is located in one of the coldest places on the planet and is situated on the vast Antarctic Plateau at an elevation of 3320 m. Continuous measurements began on December 7, 2011 and are ongoing. The median value calculated over the period (n=24506) is approximately 0.9 ng/m3 and values range from <0.1 ng/m3 up to 2.3 ng/m3. Preliminary results suggest that the Antarctic atmospheric boundary layer is a very reactive place during the periods when sunlight is present. A combination of fast and efficient oxidation processes with snow photochemistry lead to a dynamic record of Hg(0) unlike any other location. Our improved understanding of these processes will help to better constrain the cycle of Hg in the Southern Hemisphere.