Lidar observations of the middle atmospheric thermal structure over north China and comparisons with TIMED/SABER

According to the observational data for over 120 nights of the Rayleigh lidar located in Beijing, China (40.5°N, 116.2°E), the middle atmospheric thermal structure (35-85 km) over North China was obtained. Lidar observation results show good agreements with SABER temperature data sets, which justify that both the two instruments are reliable. Lidar results show significant difference with the NRLMSISE-00 empirical model and lidar temperatures are usually colder than the model data during the observational time, which may be due to the associations of high level of solar activity, greenhouse gases and the frequent haze weather in North China. To characterize the seasonal variations of the atmospheric temperature structure over Beijing, the amplitude and phase profiles of the annual, semi-annual and 3-month sinusoidal oscillations were extracted by multi-parameter sinusoidal regression. A stratospheric temperature enhancement (STE) event and a long-term mesospheric temperature inversion layer (MIL) are observed in the early winter of 2012/2013. The observed STE event could be due to the enhancement of planetary wave (k=1) activity while the long-term MIL could be due to gravity wave-planetary wave interactions in the masopause region.