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Arctic ozone loss 2011

Arctic ozone loss 2011. John Pyle Scientific Assessment Panel National Centre for Atmospheric Science, UK & Centre for Atmospheric Science Department of Chemistry University of Cambridge With thanks to Paul Newman, Martyn Chipperfield , Gloria Manney Michelle Santee and Markus Rex

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Arctic ozone loss 2011

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  1. Arctic ozone loss 2011 John Pyle Scientific Assessment Panel National Centre for Atmospheric Science, UK & Centre for Atmospheric Science Department of Chemistry University of Cambridge With thanks to Paul Newman, MartynChipperfield, Gloria Manney Michelle Santee and Markus Rex Side event to 23rd MOP / 9th COP, Bali 23 November 2011

  2. Overview • Polar ozone loss depends on temperature and inorganic halogen concentrations in lower stratosphere (depends on MP) • Assessments in 1990s recognised that could have severe Arctic ozone depletion in very cold Arctic winters • Very large ozone depletions previously reported in , e.g., 95/96, 96/97, 99/00, 04/05, 07/08 • Low temperatures into spring are key ingredient for large ozone loss

  3. Arctic 2011 Overview • Stratospheric minimum temperatures in 2010/2011 were unusually low/long lasting • Severe ozone loss (>80%), over a significant depth of atmosphere occurred. • Some records established – but consistent with our chemical understanding • But what is driving the low temperatures (natural variability vs GHG, say)?

  4. Record Arctic Ozone Loss – 2010/11 Vortex Average Loss at 20km TOMCAT/SLIMCAT CTM Cold Over -85% loss in vortex Courtesy Martyn Chipperfield www.see.leeds.ac.uk/slimcat

  5. Arctic Ozone Loss: SLIMCAT Results Updated from Feng et al. (GRL, 2007) • Arctic ozone loss is initially limited by the availability of sunlight in early winter and curtailed by the breakdown on the vortex in mid winter. • Year-to-year variations of polar Arctic O3 loss due to different meteorological conditions. • Record Arctic polar ozone loss for 2010/11 (local maximum ozone loss is ~95% at 465K by 29 March 2011). Partial column ozone loss is ~175 DU. Courtesy Chipperfield,www.see.leeds.ac.uk/slimcat

  6. High levels of Activated Chlorine observed in Arctic in March 2011 Arctic ClO in 2011 was outside the range of the 2005-2010 winter observations, and comparable to Antarctic ClO. Adapted from Figure 2 of Manney et al. (2011) - Aura MLS 2005-2010 ClO.

  7. As a result of the high Cl levels, there were large ozone losses Arctic Ozone in 2011 was outside the range of the 2005-2010 winter observations, and almost as low as Antarctic ozone. Adapted from Figure 2 of Manney et al. (2011) Aura MLS 2005-2010 Ozone.

  8. Overview • Stratospheric minimum temperatures in 2010/2011 were unusually low/long lasting • Severe ozone loss (>80%), over a significant depth of atmosphere occurred. • Some records established – but consistent with our chemical understanding • But what is driving the low temperatures (natural variability vs GHG, say)?

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