A study on surface ozone depletion episodes over the Antarctic coast

The present study on the Antarctic ozone depletion episodes (ODEs) is based on surface ozone records observed at Zhongshan Station in the Antarctic coast and related data during 2008-2013. Results show that ODEs frequently occurred in the spring at Zhongshan Station in the Antarctica. During ODEs, there existed abrupt changes in meteorological condition, including air temperature decrease, wind direction change from easterly to northerly, and wind speed decrease. More northerly winds with lower speeds from sea ice area caused the ozone concentration to maintain at a low level. The occurrence of ODE was mainly related to reactive bromine (BrO) concentration in the sea ice area. In the spring, open leads and polynyas are easily formed during the freezing and thawing processes of sea ice, when young ice and frost flowers are created by cold air sliding on the Antarctic coast. Satellite remote sensing has monitored high concentrations of active bromine derived from sea salt release in young ice areas. The reactive bromine reacts with ozone, leading to ODEs. The phenomenon occurs under natural condition without any anthropic pollution, and thus is different from ozone depletion caused by photochemical reaction in the mid and high latitudes.