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 N₂ at 263 nm and O₂ at 258 nm and the attenuation of the laser and Raman back-scattered photons by ozone absorption. This paper presents results experimental results based on the described system. To measure the concentration of ozone, they 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