Lidar observation of long-term trends and variations of stratospheric ozone and temperature over Tsukuba, Japan

Abstract

Differential absorption lidar (DIAL) at the National Institute for Environmental Studies (NIES) in Tsukuba (36°N, 140°E), Japan has been making routine observations for almost 20 years. Since 1988, more than 600 vertical profiles of stratospheric ozone and temperature have been obtained. We compared the lidar data with satellite data from the Stratospheric Aerosol and Gas Experiment (SAGE II) and assimilation data from the National Center for Environmental Prediction (NCEP). The lidar and SAGE II ozone profiles agreed within 5% in altitude range from 18 km to 40 km and within 10% up to 45 km. The lidar and NCEP temperatures agreed within 7 K in the 35- to 50-km range. Ozone levels were highest in spring at altitudes below 20 km. Above 30 km, the ozone maximum occurred during summer. The annual cycle of temperature is observed with a spring maximum for all altitudes in the 35- to 50-km range. Ozone variations caused by the quasi-biennial oscillation (QBO) and the 11-year solar cycle are discussed. The ozone trends after subtraction of the QBO and solar effects for the altitude range from 30 to 40 km are –6.0 ± 0.5%/decade for the period from 1988 to 1997 and statistically insignificant after 1998.

Acknowledgments

This study was funded by the Monitoring Program of the Center for Global Environmental Research (CGER) at NIES. The SAGE II data were obtained from NASA Langley Atmospheric Science Data Center.