Open Access

Marc von Hobe, Slimane Bekki, Stephan Borrmann, Francesco Cairo, Francesco D'Amato, Guido Di Donfrancesco, Andreas Dörnbrack, Andreas Ebersoldt, Martin Ebert, Claudia Emde, Ines Engel, Manfred Ern, Wiebke Frey, Silvia Genco, Sabine Griessbach, Jens-Uwe Grooß, Thomas Gulde, Gebhard Günther, Elisabeth Hösen, Lars Hoffmann, Viktoria Homonnai, Christopher Robert Hoyle, Ivar S.A. Isaksen, David R. Jackson, Imre M. Jánosi, Rod L. Jones, Konrad Kandler, Christoph Kalicinsky, Andrea Keil, Sergey M. Khaykin, Farahnaz Khosrawi, Rigel Kivi, Jayan Kuttippurath, Johannes Christian Laube, Franck Lefèvre, Ralph Lehmann, Sabrina Ludmann, Beiping P. Luo, Marion Marchand, Jessica Meyer, Valentin Mitev, Sergej Molleker, Rolf Müller, Hermann Oelhaf, Friedhelm Olschewski, Yvan Orsolini, Thomas Peter, Klaus Pfeilsticker, Christof Piesch, Michael C. Pitts, Lamont R. Poole, Francis D. Pope, Fabrizio Ravegnani, Markus Rex, Martin Riese, Thomas Röckmann, Bjørg Rognerud, Anke Roiger, Christian Rolf, Michelle L. Santee, Monika Scheibe, Cornelius Schiller, Hans Schlager, Matteo Siciliani de Cumis, Nikolay Sitnikov, Ole Amund Søvde, Reinhold Spang, Nicole Spelten, Frode Stordal, Olga Sumińska-Ebersoldt, Silvia Viciani, C.-Michael Volk, Marcel vom Scheidt, Alexey Ulanovski, Peter von der Gathen, Kaley A. Walker, Tobias Wegner, Ralf Weigel, Stephan Weinbruch, Gerald Wetzel, Franck G. Wienhold, Ingo Wohltmann, Wolfgang Woiwode, Isla A. K. Young, Vladimir Yushkov, Bernhard Zobrist, Fred Stroh

• The international research project RECONCILE has addressed central questions regarding polar ozone depletion, with the objective to quantify some of the most relevant yet still uncertain physical and chemical processes and thereby improve prognostic modelling capabilities to realistically predict the response of the ozone layer to climate change. This overview paper outlines the scope and the general approach of RECONCILE, and it provides a summary of observations and modelling in 2010 and 2011 that have generated an in many respects unprecedented dataset to study processes in the Arctic winter stratosphere. Principally, it summarises important outcomes of RECONCILE including (i) better constraints and enhanced consistency on the set of parameters governing catalytic ozone destruction cycles, (ii) a better understanding of the role of cold binary aerosols in heterogeneous chlorine activation, (iii) an improved scheme of polar stratospheric cloud (PSC) processes that includes heterogeneous nucleation of nitric acid trihydrate (NAT) and ice on non-volatile background aerosol leading to better model parameterisations with respect to denitrification, and (iv) long transient simulations with a chemistry-climate model (CCM) updated based on the results of RECONCILE that better reproduce past ozone trends in Antarctica and are deemed to produce more reliable predictions of future ozone trends. The process studies and the global simulations conducted in RECONCILE show that in the Arctic, ozone depletion uncertainties in the chemical and microphysical processes are now clearly smaller than the sensitivity to dynamic variability.