1. National Observatory of Athens; Greece
2. Institut Pierre Simon Laplace/Laboratoire de Météorologie Dynamique; CNRS and Ecole Polytechnique; Palaiseau France
3. Institut Pierre Simon Laplace/Laboratoire Atmosphères, Milieux, Observations Spatiales; CNRS, Université Versailles Saint Quentin; Guyancourt France
4. UMR 8190 LATMOS, CNRS and UVSQ; Sorbonne Universités, UPMC Univ Paris 6; France
5. Department of Environmental Sciences; Institute for Atmospheric and Climate Science (IACETH); ETH Zurich Switzerland