Seasonal Variation of Atmospheric Temperature and Gravity Wave Activity over Beijing Area

By using Rayleigh lidar data, the seasonal variations of atmospheric temperature and gravity wave activity at 30~70km height over Beijing area are analyzed. Results show that the atmospheric temperature has an obvious annual cycle variation. The highest temperature in the stratopause appears in June or July, which is about 270K. The lowest temperature at 70km height of the middle layer also occurs in June or July, which is about 200K. Taking the data of 14 October 2014 as an example to analyze the potential energy density of gravity wave, we find that dissipation exists in the potential energy of gravity waves under 50km height, while gravity waves propagate up with no dissipation over 50km height. Using the average potential energy density at 35~50km height, the seasonal variation of the gravity waves activities intensity is analyzed. The gravity waves activities have an obvious annual cycle. The average potential energy density is 18J·kg^-1 and 8J·kg^-1 in winter and summer respectively. The gravity waves activities intensity in winter are about two times of that in summer. In addition, the variation of gravity waves potential energy density with height in spring, summer, autumn and winter are analyzed. The analysis shows that the potential energy density of gravity waves is changing with different seasons and heights.