Jean-Claude Roger, University of Maryland College Park, Department of Geographical Sciences, College Park, MD, United States, Eric Vermote, NASA Goddard Space Flight Center, Terrestrial Information Systems Laboratory, Greenbelt, MD, United States, Sergii Skakun, University of Maryland College Park, College Park, United States, Belen Franch, University of Valencia, Valencia, Spain, Oleg Dubovik, Laboratoire d'Optique Atmosphérique, CNRS/University of Lille, Lille, France, Brent Holben, NASA Goddard Space Flight Center, Greenbelt, MD, United States, Natacha Kalecinski, University of Maryland, College Park, United States and Christopher Owen Justice, University of Maryland, Geographical Sciences, College Park, MD, United States