1. Consiglio Nazionale delle Ricerche, Istituto di Metodologie per l’Analisi Ambientale, Tito Scalo, Italy;
2. IAASARS, National Observatory of Athens, Athens, Greece;
3. Izaña Atmospheric Research Center, State Meteorological Agency (AEMET), Santa Cruz de Tenerife, Spain;
4. IAASARS, National Observatory of Athens, and Research Centre for Atmospheric Physics and Climatology, Academy of Athens, Athens, Greece;
5. Royal Belgian Institute for Space Aeronomy (BIRA-IASB), Brussels, Belgium;
6. European Centre for Medium-Range Weather Forecasts, Reading, United Kingdom;
7. Agricultural University of Iceland, Borgarnes, Iceland, and Czech University of Life Sciences, Prague, Czech Republic;
8. Université de Paris Cité and Univ. Paris Est Creteil, CNRS, LISA, Paris, France;
9. Federal Office of Meteorology and Climatology MeteoSwiss, Payerne, Switzerland;
10. Physikalisch-Meteorologisches Observatorium Davos, World Radiation Center, Switzerland;
11. Institute of Meteorology and Climate Research, Karlsruhe Institute of Technology, Karlsruhe, Germany;
12. Republic Hydrometeorological Service of Serbia, and Institute of Physics, Belgrade, Serbia;
13. Barcelona Supercomputing Center, and Catalan Institution for Research and Advanced Studies (ICREA), Barcelona, Spain;
14. German Aerospace Center (DLR), German Remote Sensing Data Center Atmosphere, Oberpfaffenhofen, Germany;
15. Izaña Atmospheric Research Center, State Meteorological Agency (AEMET), Santa Cruz de Tenerife, and Instituto de Produciton Naturales y Agrobiología IPNA CSIC, Tenerife, Spain;
16. Caribbean Institute for Meteorology and Hydrology, Bridgetown, Barbados;
17. National Institute for Environmental Studies, Tsukuba, Japan;
18. Spanish Meteorological Agency, AEMET, Barcelona, Spain;
19. Faculty of Agriculture, University of Belgrade, Serbia;
20. Aerosol Physics and Environmental Physics, Faculty of Physics, University of Vienna, Vienna, Austria;
21. Barcelona Supercomputing Center, Barcelona, Spain, and Science and Innovation Department, World Meteorological Organization, Geneva, Switzerland