Three Decades of Tropospheric Ozone Lidar Development at Garmisch-Partenkirchen

Abstract. Since 1988 two ozone lidar systems have been developed at IMK-IFU (Garmisch-Partenkirchen, Germany). A stationary system, operated at the institute, has yielded about 5000 vertical profiles of ozone from next to the ground to typically 3 km above the tropopause and has contributed data for a large number of scientific investigations. A mobile system was successfully operated in a number of field campaigns after its completion in 1996, before it was destroyed in major flooding in May 1999. Both systems combine a high data quality with high vertical resolution dynamically varied between 50 m in the lower troposphere and 250–500 m below the tropopause (stationary system). The stationary system has been gradually upgraded over the years. The noise level of the raw data has reached a level of about ±1 × 10-6 of the input range of the transient digitizers after minor smoothing. As a consequence, uncertainties of the ozone mixing ratios of 1.5 to 4 ppb have been achieved up to about 5 km. The performance in the upper troposphere, based on the wavelength pair 292 – 313-nm varies between 5 and 15 ppb, depending on the absorption of the 292-nm radiation in ozone and the solar background. In summer it is, therefore, planned to extend the measurement time for 41 s to a few minutes in order to improve the performance. For longer time series automatic data acquisition has been used. The number of measurements per year has been confined to less than 600 since fully automatic data evaluation has, still, had its limitations and some manual actions are needed.