Pier Luigi Vidale, University of Reading, Reading, RG6, United Kingdom, Kevin Hodges, University of Reading, Reading, United Kingdom, Malcolm J Roberts, Met Office Hadley center for Climate Change, Exeter, United Kingdom, Kristian Strommen, University of Oxford, Oxford, Oxfordshire, United Kingdom, Paolo Davini, CNR Institute of Atmospheric Sciences and Climate, Torino, Italy, Antje Weisheimer, University of Oxford, Department of Physics, National Centre for Atmospheric Science (NCAS),, Oxford, United Kingdom and Susanna Corti, CNR Institute of Atmospheric Sciences and Climate, Bologna, Italy