Surface ozone monitoring and background characteristics at Zhongshan Station over Antarctica

Seasonal variation in surface ozone and the relationship between the background ozone concentration and wind were evaluated at Zhongshan Station, Antarctica using 2008 data. The wind frequency from the station area was only 2%, while the prevailing wind frequency was much larger (79.2%). This indicates that the surface ozone observations were not affected by the human activities at the station, and therefore could be counted as background concentrations of surface ozone along Antarctic coast. The concentration of surface ozone shows a distinct annual variation with the yearly mean of 25.0 nmol mol⁻¹ and the maximum in winter, the minimum in summer. The surface ozone concentration had a strong negative correlation with ultraviolet radiation, and the mean values during polar night were one to two times higher than those in summer. These results imply that photochemical destruction of ozone dominates over Antarctica. The ozone depletion events at Zhongshan Station were obviously related to lower temperatures and higher BrO concentrations. Backward trajectory analysis reveals that the ozone depletion events are predominately caused by the high BrO concentrations.