Tropospheric Ozone Depletion and Bromine Explosions

Tropospheric ozone depletion events during the Antarctic spring of 06/07 and 07/08 were observed. DOAS measurements of near surface BrO and O3 concentrations were made at three locations: Cape Bird (06-07 and 07-08 seasons), the sea ice below Arrival Heights (06-07 and 07-08 seasons) and from sea ice close to Inaccessible Island (07-08 season). BrO slant columns were measured, near surface O3 were determined and snow samples were collected and analysed for mercury and pH. Two ozone depletion events were captured in the 06-07 season and 5 were captured in the 07-08 season. The dataset for the 07-08 season consists of 6 weeks measurements on the sea-ice close to Inaccesible Island, 4 concurrent weeks with a second DOAS instrument on the sea ice below Arrival Heights and then 5 weeks at Cape Bird. Calibrations of the instruments were made at Arrival Heights. Vertical profiles of temperature, humidity and ozone up to 300 m were measured occasionally.