Zhen Liu, University of Edinburgh, School of GeoSciences, Edinburgh, United Kingdom, Massimo A Bollasina, University of Edinburgh, Edinburgh, EH9, United Kingdom, Laura Wilcox, University of Reading, National Centre for Atmospheric Science, Reading, RG6, United Kingdom, Jill S Johnson, University of Leeds, Institute for Climate and Atmospheric Science, School of Earth and Environment, Leeds, United Kingdom and Leighton Regayre, University of Leeds, Leeds, LS2, United Kingdom