Intense Arctic Ozone Depletion in the Spring of 2011

Observations of record-breaking ozone depletion during the Arctic spring of 2011 were made at 76 degrees N in Thule, Greenland. The ozone total column amount of 290 DU measured on 18 March 2011 is the lowest value from the 12-year observation record and represents an ozone depletion of up to 48% of a typical March column. The unique 2010-11 vortex was characterized by sustained low stratospheric temperatures and stability that resisted breakup through March. Simultaneous observations of O-3, HF, HCl, HNO3, and CIONO2 demonstrate strong subsidence and substantial conversion of chlorine from its normal reservoirs.