Unprecedented Arctic Ozone Loss in 2011: An Echo of the Antarctic

Chemical ozone destruction occurs over both polar regions in local winter/spring. In the Antarctic, an ozone hole currently forms every year via near-complete chemical destruction of vortex ozone between ~15 and 22km. In contrast, Arctic ozone loss is highly variable and has heretofore been much more limited. In early 2011, however, Arctic chemical ozone destruction approached that in the Antarctic ozone hole. While other Arctic winters had lower temperatures at particular times, and in 1997 temperatures were conducive to chemical processing as late in the season as in 2011, no other Arctic winter had as continuous and prolonged a cold period over the entire lower stratosphere as did 2010/2011. The processes leading to the unprecedented chemical loss in 2011 are detailed using aerosol (PSC) profiles from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) and trace gas profiles (including HNO3, reservoir (HCl) and reactive (ClO) chlorine species,and ozone) from the Aura Microwave Limb Sounder (MLS). Ozone Monitoring Instrument (OMI) total ozone measurements show the extent of column loss in comparison to other Arctic winters and the Antarctic. The extent of Arctic chemical ozone loss in the 2010/2011 winter was, for the first time, large enough to be clearly identifiable as an Arctic ozone hole.