Tropospheric ozone measurements over the Great Athens Area during the medcaphot-trace campaign with a new shot-per-shot dial instrument: experimental system and results

Within the MEDCAPHOT-TRACE program of the European Community for studying the photochemical air pollution over the Great Athens Area, we report on 3-D lidar measurements of tropospheric ozone. After a general presentation of the DIAL technique, the experimental layout of our system which is equipped with a unique capability for real-time analysis of each individual optical backscattered signal is briefly described and its performance is assessed. The temporal evolution of the ozone concentration up to the top of the boundary layer is then followed over a few days. In particular, the first day of the photochemical smog episode is presented and commented.