Four‐year aerosol observations with a Raman lidar at Thessaloniki, Greece, in the framework of European Aerosol Research Lidar Network (EARLINET) - V. Amiridis; Balis, D. S.; S. Kazadzis; A. Bais; Giannakaki, E.; Papayannis, A.; Zerefos, C. (Journal of Geophysical Research: Atmospheres, 2005)