Inertial gravity waves study with Rayleigh Doppler Lidar long-term observation

Abstract

Rayleigh Doppler Lidar was often used for horizontal wind speed and temperature observation in stratosphere and middle atmosphere. University of Science and Technology of China introduced a Doppler frequency calibration device in the newly developed Lidar system, which can achieve high - precision observation of the horizontal wind speed and temperature of 15-70 km of the atmosphere under clear sky. The continuous observation data of the horizontal wind speed and temperature of the Lidar system was analyzed in the northwest area of China from September to October, 2018. The gravity wave parameters, such as the vertical wavelength, natural period, horizontal and vertical propagation directions, were reached by extracting wind speed and temperature disturbance, spectrum analysis, gravity wave model parameter fitting and Hodograph. A total of 384 gravity waves were extracted from 224 h of observation data. In these waves, 53.9% of the vertical propagation direction is upward. Fluctuation amplitude of wind speed and temperature is concentrated at 10-20 m/s and 10-20 K. More than 70% of the vertical wavelength is in a range of 5-10 km, and fluctuations of more than 15 km rarely occurred. The horizontal wavelength is centered at 100 km to 200 km, and the dominant intrinsic period is less than 5 h. The horizontal propagation direction is dominated by the opposing directions of 20 ° west - northwest and 20° east -south. The distribution characteristics of gravity waves are consistent with the local dominant wind direction and the distribution of surrounding mountains.