Georgiy L Stenchikov, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia, Mark R Schoeberl, Science and Technology Corporation, Earth Sciences, Boulder, CO, United States, Ewa Bednarz, CIRES / NOAA Chemical Sciences Laboratory, Boulder, United States, Ilaria Quaglia, National Center for Atmospheric Research, Atmospheric Chemistry Observations and Modeling Laboratory, Boulder, United States, Zhihong Zhuo, University of Quebec in Montreal (UQAM), Department of Earth and Atmospheric Sciences, Montreal, QC, Canada, Eric L Fleming, NASA Goddard Space Flight Center, Greenbelt, MD, United States, Yi Huang, McGill University, Atmospheric and Oceanic Sciences, Montreal, QC, Canada, Pasquale Sellitto, Université Paris Est Créteil, Université de Paris-Cité, CNRS, Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA-IPSL), Créteil Cedex, France, Claudia Timmreck, Max Planck Institute for Meteorology, Hamburg, Germany, Matthew Toohey, University of Saskatchewan, Saskatoon, Canada and Jun Wang, University of Iowa, Chemical and Biochemical Engineering, Iowa City, IA, United States