Abstract

25 years of extensive research following the discovery of the “Ozone Hole” by Farman et al., have unraveled the relationship between the rapid decline in ozone over the poles in spring and anthropogenic emissions of CFCs and the Montreal Protocol and its subsequent amendments banning these substances will eventually lead to full recovery of the ozone layer. However, we have not yet reached full quantitative understanding of all the chemical and physical processes governing stratospheric ozone at high latitudes, and our predictive capabilities in a world of rapid climate change – possibly even involving changes to the stratosphere due to human geoengineering – are far from sufficient.

The EU-project RECONCILE (Reconciliation of essential process parameters for an enhanced predictability of arctic stratospheric ozone loss and its climate interactions) sets out to resolve the open issues and to improve current predictive models. Using laboratory experiments, field measurements and modeling studies, four central objectives are being addressed:

1. Reach quantitative understanding of the chemistry leading to polar ozone depletion
2. Improve our understanding of polar stratospheric cloud (PSC) microphysics and heterogeneous chlorine activation
3. Quantify the flux and mixing of air through the vortex edge and its impact on polar and mid-latitude ozone
4. Incorporate the improved parameterisations into a Chemistry Climate Model (CCM) to generate more reliable predictions for the future evolution of the ozone layer and its effects and sensitivities to climate, and test the improved CCM simulations against observed trends.

In my presentation, I will discuss open questions related to polar ozone and explain, how we will try to answer them within RECONCILE . I will also present first results from the recent field campaign with the high-flying aircraft M55 -Geophysica from Kiruna, Sweden .