1. Institute of Astronomy, Astrophysics, Space Applications and Remote Sensing (IASSARS), National Observatory of Athens, 15236 Athens, Greece
2. Laboratory of Atmospheric Physics, Physics Department, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
3. Meteorological Institute, Ludwig Maximilian University of Munich, 80539 Munich, Germany
4. West African Science Service Centre on Climate Change and Adapted Land Use (WASCAL), Atlantic Technical University, Sao Vicente C.P. 163, Cape Verde
5. European Space Agency Centre for Earth Observation (ESA/ESRIN), 00044 Frascati, Italy
6. European Space Agency European Space Research and Technology (ESA/ESTEC), 2201 AZ Noordwijk, The Netherlands