Inter-annual variability of surface ozone at coastal (Dumont d’Urville, 2004–2014) and inland (Concordia, 2007–2014) sites in East Antarctica

• Published in: Atmospheric Chemistry and Physics
• Main Authors: Legrand, M., Preunkert, S., Savarino, J., Frey, M.M., Kukui, A., Helmig, D., Jourdain, B., Jones, A. E., Weller, Rolf, Brough, N., Gallée, H.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: COPERNICUS GESELLSCHAFT MBH 2016
• Subjects: Antarctic; Weddell Sea; East Antarctica; Neumayer; West Antarctica; Weddell; South Pole; Dumont d'Urville; Dumont-d'Urville; Concordia Station; Dumont d’Urville; Antarc*; Antarctica; Sea ice; South pole
• Online Access: https://epic.awi.de/id/eprint/40194/; https://epic.awi.de/id/eprint/40194/1/Michel_acp-16-8053-2016.pdf; https://hdl.handle.net/10013/epic.48306; https://hdl.handle.net/10013/epic.48306.d001

Surface ozone has been measured since 2004 at the coastal East Antarctic site of Dumont d'Urville (DDU) and since 2007 at the Concordia station located on the high East Antarctic plateau. This paper discusses long-term trends, seasonal and diurnal cycles, as well as inter-annual summer variability observed at these two East Antarctic sites. At Concordia, near surface ozone data were complemented by balloon soundings and compared to similar measurements done at the South Pole. The DDU record is compared to those obtained at the coastal site of Syowa also located in East Antarctica, as well as the coastal sites of Neumayer and Halley, both located at the coast of the Weddell Sea in West Antarctica. Surface ozone mixing ratios exhibit very similar seasonal cycle at Concordia and the South Pole. However, in summer the diurnal cycle and the vertical distribution of ozone above the snow surface are different at the two sites with a drop of ozone in the afternoon at Concordia and not at the South Pole, and a far well-mixed rich ozone layer within the lower 250 m at Concordia than at the South Pole during sunlight hours. These differences are related to different solar radiation and wind regimes encountered at these two inland sites. DDU appears to be the coastal site where the impact of the late winter/spring bromine chemistry is the weakest, but where the impact of NOx snow emissions from the high Antarctic plateau is the highest. The highest impact of the bromine chemistry is seen at Halley and Neumayer, and to a lesser extent at Syowa. These three sites are only weakly impacted by the NOx chemistry and the net ozone production occurring on the high Antarctic plateau. The differences in late winter/spring are attributed to the abundance of sea-ice offshore the sites whereas those in summer are related to the topography of East Antarctica that promotes the katabatic flow bringing oxidant-rich inland air masses to the site. There appears to be a decreasing trend in summer at the two East Antarctic sites of Concordia and DDU over the most recent period (2004/2007–2014). Further researches including continuing monitoring are needed at these two sites to better separate effect of synoptic transport from possible change of NOx snow emissions in response to change of the stratospheric ozone layer.