One year of tropospheri clidar measurements of aerosol extinction and backscatter

The aerosol lidar system operational at IMAA-CNR in Tito Scalo (PZ) (Southern Italy, 40°36'N, 15°44'E, 820 m
 above sea level) is part of the EARLINET project. Systematic lidar measurements of aerosol backscatter and
 extinction in the troposphere have been performed since May 2000. Aerosol backscatter measurements were
 performed at both 355 nm and 532 nm, while aerosol extinction coeffi cient were retrieved from simultaneous N2
 Raman backscatter signals at 386.6 nm. The observations were performed on a regular schedule of two night time
 measurements per week (around sunset) and one daytime measurement per week (around 13:00 UTC). Furthermore,
 special observations concerning Saharan dust outbreaks have been carried out. Starting in May 2000 the lidar
 measurements performed in Tito Scalo have been collected and analysed. Preliminary results regarding the fi rst
 year of measurements are reported. In particular, the evolution of the aerosol integrated backscatter and extinction
 as well as of the mean value of the lidar ratio in the whole aerosol layer is reported. Results show clear evidence
 of seasonal variation of the observed parameters, with higher values and greater variability during summertime