NIES Ozone Lidar- new analysis and results

Abstract. National Institute for Environmental Studies (NIES) in Japan has measured the vertical profile of ozone by laser radar (lidar) at Tsukuba (36 N, 140 E) since 1988. The version-2 algorism for retrieval of ozone, temperature and aerosols in the stratosphere was developed. In the algorithm, new method to obtain the upper boundary of aerosol layer and the extinction/backscatter ratio of aerosols are used for more accurate determination of the vertical profiles of aerosols and more accurate correction of systematic errors due to the aerosols in the vertical profiles of ozone. Improvements in signal processing are incorporated for corrections of systematic errors such as the signal induced noise and the dead time effect. As the results of these corrections, improved ozone profiles for 1988-2003 are achieved. Comparison of the ozone profiles measured by lidar and SAGE II showed agreement within 5 % in altitude range from 18 km to 40 km when the version-2 algorism and a potential vorticity selection method was applied. Lidar system and Algorithm The lidar is a typical UV DIAL (Differential Absorption Lidar) system with high power lasers and a large telescope. Several changes of the system have been made since the installation in 1988. 308nm, 339nm, 351 nm lasers and 2 m Cassegrain type telescope were used for the DIAL ozone measurements during a period of 1988-1995. For the better efficiency of the system, the 308 nm laser was replaced by the high power system of LPX 150 in 1995. In 1996, the 351 nm and the 339 nm Raman lasers were removed and 355 nm Coherent InfinityTM Nd:YAG laser was installed. Also th