Comparison of ozone profiles derived from ground-based microwave and lidar measurements

A ground-based microwave heterodyne spectrometer for detection of middle atmospheric ozone has been developed at Max-Planck-Institut für Aeronomie (MPAE), Germany. It was in operation from October 1995 until May 1996 at the Arctic Lidar Observatory for Middle Atmospheric Research (ALOMAR) near Andenes, Norway (69.3 N, 16.0 E). The microwave system provided ozone profiles in the altitude range from 15 to 80 km. During this period, a lidar system has been operated at the same location. The ozone profiles from the lidar covered the altitude range from 10 to 44 km. An intercomparison of 60 ozone profiles between the two instruments shows a good agreement. The mean microwave data were lower than the convolved mean lidar data by only 3 % at 24 —38km, and higher by only 5 % at 20 — 24km. Above 38 km the lidar measurements become more and more noise dominated, resulting in increasing errors and disagreement with the microwave measurements. The intercomparison suggests that the ozone profiles, provided by the microwave instrument, are not modulated by tropospheric transmission variations and that the other systematic error sources like residual baselines are properly modeled.