An excimer laser-based Lidar system for tropospheric ozone measurements

A ground based Raman Lidar has been developed for daytime and nighttime ozone monitoring in the lower troposphere (0.2 - 2 Km). The system unitizes a 30" Cassegranian telescope and a KrF excimer laser transmitter operating at 248 nm and up to 20 W average power. Both analog and photon-counting detection methods are designed to produce measurements. The dominant physics governing the system is the Raman scattering of the laser photons by N-2 at 263 nm and O-2 at 258 run and the attenuation of the laser and Raman back-scattered photons by ozone absorption [1-3]. This paper presents results experimental results based on the described system. To measure the concentration of ozone, we calculate the single and double ratio of the pair 263/258 nm throughout the range up to 2 Km in the lower troposphere. The Lidar results indicate that long counting times or higher counting rates are essential to achieve high accuracy measurements.