Kirstin Krüger, University of Oslo, Department of Geosciences, Oslo, Norway, Masatomo Fujiwara, Hokkaido University, Faculty of Environmental Earth Science, Sapporo, Japan, Cameron R Homeyer, University of Oklahoma, School of Meteorology, Norman, OK, United States, Bernard Legras, Laboratoire de Météorologie Dynamique ENS, Paris, France, Gloria L Manney, NorthWest Research Associates, Inc, Socorro, NM, United States; New Mexico Institute of Mining and Technology, Department of Physics, Socorro, NM, United States, Matthias Nützel, German Aerospace Center DLR Oberpfaffenhofen, Oberpfaffenhofen, Germany, Susann Tegtmeier, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany, Tao Wang, NASA Goddard Space Flight Center, Greenbelt, United States and Jonathan Wright, Tsinghua University, Department of Earth System Science, Beijing, China