Lindsay Lee¹, Claudia Timmreck², Graham W Mann¹, Valentina Aquila³, Rene Hommel⁴, Anja Schmidt⁵, Christoph Bruehl⁶, Simon A Carn⁷, Mian Chin⁸, Sandip Dhomse¹, Thomas Diehl⁹, Jason M English¹⁰, Michael J Mills¹¹, Ryan Neely¹², Jianxiong Sheng¹³, Matthew Toohey¹⁴, Debra Weisenstein¹⁵, Daniele Visioni¹⁶, Brian Zambri¹⁷ and Timofei Sukhodolov¹⁸, (1)University of Leeds, Leeds, LS2, United Kingdom, (2)Max Planck Institute for Meteorology, Hamburg, Germany, (3)American University, Department of Environmental Science, Washington, DC, United States, (4)Hommel and Graf Environmental, Hamburg, Germany, (5)University of Cambridge, Cambridge, United Kingdom, (6)Max Planck Inst Chemie, Mainz, Germany, (7)Michigan Technological University, Department of Geological and Mining Engineering & Sciences, Houghton, MI, United States, (8)NASA Goddard SFC, Greenbelt, MD, United States, (9)11European Commission Joint Research Centre, Ispra, Italy, (10)Laboratory for Atmospheric and Space Physics, Boulder, CO, United States, (11)National Center for Atmospheric Research, Atmospheric Chemistry, Observations, and Modeling Laboratory, Boulder, CO, United States, (12)University of Leeds, Leeds, United Kingdom, (13)ETH Zurich, Zurich, Switzerland, (14)GEOMAR, Kiel, Germany, (15)Harvard University, Cambridge, MA, United States, (16)Cornell University, Ithaca, United States, (17)Rutgers University New Brunswick, New Brunswick, NJ, United States, (18)PMOD WRC Physical Meteorological Observatory Davos and World Radiation Center, Davos Dorf, Switzerland