On the variability of atmospheric ²²²Rn activity concentrations measured at Neumayer, coastal Antarctica

• Main Authors: R. Weller, I. Levin, D. Schmithüsen, M. Nachbar, J. Asseng, D. Wagenbach
• Format: Article
• Language: English
• Published: Copernicus Publications 2014-04-01
• Series: Atmospheric Chemistry and Physics
• Online Access: http://www.atmos-chem-phys.net/14/3843/2014/acp-14-3843-2014.pdf
• ISSN: 1680-7316; 1680-7324

We report on continuously measured ²²²Rn activity concentrations in near-surface air at Neumayer Station in the period 1995–2011. This 17-year record showed no long-term trend and has overall mean ± standard deviation of (0.019 ± 0.012) Bq m⁻³. A distinct and persistent seasonality could be distinguished with maximum values of (0.028 ± 0.013) Bq m⁻³ from January to March and minimum values of (0.015 ± 0.009) Bq m⁻³ from May to October. Elevated ²²²Rn activity concentrations were typically associated with air mass transport from the Antarctic Plateau. Our results do not support a relation between enhanced ²²²Rn activity concentrations at Neumayer and cyclonic activity or long-range transport from South America. The impact of oceanic ²²²Rn emissions could not be properly assessed but we tentatively identified regional sea ice extent (SIE) variability as a significant driver of the annual ²²²Rn cycle.