Manfred Birk, Deutsches Zentrum fuer Luft- und Raumfahrt (DLR), remote sensing technology institute, Wessling, Germany, Mathieu Quatrevalet, German Aerospace Center (DLR), Institute of Atmospheric Physics, Oberpfaffenhofen, Germany, Melanie Ghysels, Université de Reims Champagne Ardenne, Reims, France, Ha Tran, CNRS/IPSL/UPMC, Laboratoire de Météorologie Dynamique, Paris, French Guiana, Thibault Delahaye, CNRS, IPSL, Analyse du Rayonnement Atmosphérique, Palaiseau, France, Joseph T Hodges, NIST, Gaithersburg, MD, United States, Zachary Reed, National Institute of Standards and Technology (NIST), Gas Sensing Metrology Group, Gaithersburg, MD, United States, Georg Wagner, Deutsches Zentrum fuer Luft und Raumfahrt (DLR), Remote Sensing Technology Institute, Wessling, Germany, Victor Gorshelev, University of Bremen, Institute of Environmental Physics, Bremen, Germany and John Philip Burrows, Institute of Environmental Physics, University of Bremen, Bremen, Germany