1. Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing (IAASARS), National Observatory of Athens, GR-15 236 Penteli, Greece
2. Department of Physics, Section of Environmental Physics-Meteorology, National and Kapodistrian University of Athens, GR-157 84 Zografou, Greece
3. Department of Physics, Aristotle University of Thessaloniki, GR-54124 Thessaloniki, Greece
4. Department of Geography, Harokopion University of Athens (HUA), GR-17676 Kallithea, Greece
5. Department of Meteorology and Climatology, School of Geology, Aristotle University of Thessaloniki, GR-54124 Thessaloniki, Greece
6. Finnish Meteorological Institute (FMI), FI-00560 Helsinki, Finland
7. Atmospheric Chemistry Research Group, Chemical Resource Beneficiation, North-West University, Potchefstroom ZA-2531, South Africa
8. Leibniz Institute for Tropospheric Research (TROPOS), 04318 Leipzig, Germany