Robert P Damadeo, NASA Langley Research Center, Hampton, VA, United States, Irina V Petropavlovskikh, Cooperative Institute for Research in Environmental Sciences, Boulder, CO, United States, Sophie Godin-Beekman, LATMOS Laboratoire Atmosphères, Milieux, Observations Spatiales, Paris Cedex 05, France, Daan Hubert, Belgian Institute for Space Aeronomy, Brussels, Belgium, Birgit Hassler, Deutsches Zentrum für Luft- und Raumfahrt, Institut für Physik der Atmosphäre, Oberpfaffenhofen, Germany, Viktoria Sofieva, Finnish Meteorological Institute, Helsinki, Finland, Kai-Lan Chang, NOAA Boulder, Boulder, CO, United States, Kleareti Tourpali, Aristotle University of Thessaloniki, Thessaloniki, Greece, William Ball, PMOD WRC Physical Meteorological Observatory Davos and World Radiation Center, Davos, Switzerland, Stacey M Frith, NASA Goddard SFC, Greenbelt, MD, United States, Jeannette Wild, NOAA NWS NCEP, Climate Prediction Center, College Park, MD, United States, Lucien Froidevaux, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, United States, Sean M Davis, Chemical Sciences Division, NOAA Earth System Research Laboratory; Cooperative Institute for Research in Environmental Sciences, Boulder, CO, United States, D A Degenstein, University of Saskatchewan, Department of Physics & Engineering Physics, Saskatoon, SK, Canada, Daniel Zawada, University of Saskatchewan, Saskatoon, SK, Canada, Alexandra Laeng, Karlsruhe Institute of Technology, IMK-ASF, Karlsruhe, Germany and Christos S Zerefos, Rsrch Cnter Atmos Phy & Clim, Academy of Athens, Athens, Greece