Arctic ozone loss 2011

John Pyle

Scientific Assessment PanelNational 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

Side event to 23rd MOP / 9th COP, Bali

23 November 2011

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

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)?

Record Arctic Ozone Loss – 2010/11

Vortex Average Loss at 20km TOMCAT/SLIMCAT CTM

Courtesy Martyn Chipperfieldwww.see.leeds.ac.uk/slimcat

Over -85% loss in vortex

Cold

Arctic Ozone Loss: SLIMCAT Results

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

Updated from Feng et al. (GRL, 2007)

High levels of Activated Chlorine observed in Arctic in March 2011

Adapted from Figure 2 of Manney et al. (2011) - Aura MLS 2005-2010 ClO.

Arctic ClO in 2011 was outside the range of the 2005-2010 winter observations, and comparable to Antarctic ClO.

As a result of the high Cl levels, there were large ozone losses

Adapted from Figure 2 of Manney et al. (2011) Aura MLS 2005-2010 Ozone.

Arctic Ozone in 2011 was outside the range of the 2005-2010 winter observations, and almost as low as Antarctic ozone.

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)?