Arctic Ozone Depletion
Wuhu Feng, Sandip Dhomse and Martyn Chipperfield
Background
Large ozone loss occurs essentially every year during the Antarctic spring – the so-called Antarctic Ozone Hole. This is caused by the activation of chlorine on polar stratospheric clouds (PSCs) which form in the cold winter stratosphere. Active chlorine (e.g. ClO) and bromine (BrO) species rapidly destroy ozone in sunlight. Although the same chemical processes occur in the Arctic the loss is smaller and more variable than the Antarctic. This is due to the different stratospheric meteorology. Some warm Arctic winters show no ozone depletion; cold winters can show considerable loss.
Arctic Winter 2010/11
The Arctic winter of 2010/11 was cold and allowed PSCs to persist for a long time. This provided conditions conducive for extensive ozone depletion. Figure 1 shows calculations of polar ozone depletion from the SLIMCAT 3D model for the past 18 years. Winter 2010/11 stands out as the winter with the largest loss inside the polar vortex – reaching 85% at 20km. The persistence of PSCs late in the winter allow the ozone loss to continue through to late March. In contrast the recent winter of 2012/13 was warm, had few PSCs and therefore low depletion.
The Arctic winter/spring stratosphere remains susceptible to large ozone loss while chlorine and bromine levels remain high. This will be the case for the next few decades, before the Montreal Protocol causes a reduction back to the levels of the 1980s.
Animations of modelled polar ozone depletion are linked from the main TOMCAT/SLIMCAT page.
Publications
Adams, C.; Strong, K.; Zhao, X.; Bassford, MR; Chipperfield, MP; Daffer, W; Drummond, JR; Farahani, EE; Feng, W; Fraser, A; Goutail, F; Manney, G; McLinden, CA; Pazmino, A; Rex, M; Walker, KA, Severe 2011 ozone depletion assessed with 11 years of ozone, NO2, and OClO measurements at 80 degrees N, Geophys. Res. Lett., 39, L05806 doi:10.1029/2011GL050478, 2012.
Chipperfield, M.P., W. Feng, and M. Rex, Arctic Ozone Loss and Climate Sensitivity: Updated Three-Dimensional Model Study, Geophys. Res. Lett., 32(11), L11813, doi:10.1029/2005GL022674, 2005.
Feng W.; Chipperfield M. P.; Davies S.; et al., Modelling the effect of denitrification on polar ozone depletion for Arctic winter 2004/2005, Atmos. Chem. Phys., 11, 6559-6573, doi:10.5194/acp-11-6559-2011, 2011.
Lindenmaier, R.; Strong, K.; Batchelor, R. L.; Chipperfield, MP; Daffer, WH; Drummond, JR; Duck, TJ; Fast, H; Feng, W; Fogal, PF; Kolonjari, F; Manney, GL; Manson, A; Meek, C; Mittermeier, RL; Nott, GJ; Perro, C; Walker, KA, Unusually low ozone, HCl, and HNO3 column measurements at Eureka, Canada during winter/spring 2011, Atmos. Chem. Phys., 12, 3821-3835, doi:10.5194/acp-12-3821-2012, 2012.