Freja F Oesterstroem, Aarhus University, Department of Environmental Science, Roskilde, Denmark; Harvard University, Cambridge, MA, United States, Michelle L Santee, JPL, Pasadena, United States, Martyn Chipperfield, University of Leeds, School of Earth and Environment, Leeds, United Kingdom, Stephanie Evan, CIRES, Boulder, United States, Dan Smale, National Institute of Water & Atmospheric Research (NIWA), Lauder, New Zealand, Krzysztof Wargan, NASA Goddard Space Flight Center, Greenbelt, United States, David M Wilmouth, Harvard University, Cambridge, United States and Ingo Wohltmann, Alfred Wegener Institute, Helmholtz-Center for Polar and Marine Research Potsdam, Potsdam, Germany