Stable isotopes, bromine, iodine and sodium in surface snow along the 2013 Talos Dome - GV7 traverse (Northern Victoria Land, East Antarctica)

Halogen chemistry in the polar regions occurs through the release of sea salt rich aerosols from sea ice surfaces and organic compounds from algae colonies living within the sea ice environment. Measurements of halogen species in polar snow samples are limited to a few sites although they are shown to be closely related to sea ice extent. We examine here total bromine, iodine and sodium concentrations in a series of 2 m cores collected during a traverse from Talos Dome (72°48' S, 159°06' E) to GV7 (70°41' S, 158°51' E), analyzed by Inductively Coupled Plasma Sector Field Mass Spectrometry (ICP-SFMS) at a resolution of 5 cm. We find a distinct seasonality of the bromine enrichment signal in all cores, with maxima during the austral late spring. Iodine showed average concentrations of 0.04 ppb with little variability. No distinct seasonality was found for iodine and sodium. The transect revealed homogeneous fluxes for the three chemical species along the transect, due to competing effects of air masses originating from the Ross Sea and the Southern Ocean. The flux measurements are consistent with the uniform values of BrO and IO detected from satellite observations. Similar trends are found for annual bromine enrichment and 130-190° E First Year Sea Ice for the 2010-2013 period.