Systematic lidar ratio measurements in the frame of EARLINET

Systematic lidar ratio measurements have been performed in ten different lidar stations in Europe in the framework of the EARLINET project. Lidar ratio data have been collected and this is by far the largest data set of lidar ratio data on continental scale covering 31 months of systematic observations. A preliminary statistical analysis on these climatological data has been performed. Mean values of the lidar ratio data, in the dust layer above each lidar station, starting from all regular measurements in the period May 2000 - December 2002, have been calculated and for each station the corresponding seasonal variation and frequency distribution have been studied. Moreover, an analysis of the correlation between lidar ratio measurements and air mass origin has been performed using back-trajectories calculated by the German Weather Service.