From Aug.2013 to Oct.2015,a Rayleigh lidar has been used to study the middle atmosphere at Golmud(36.25°N,94.54°E),Qinghai,located in the northeastern part of the Tibetan Plateau.Mesospheric density profiles...From Aug.2013 to Oct.2015,a Rayleigh lidar has been used to study the middle atmosphere at Golmud(36.25°N,94.54°E),Qinghai,located in the northeastern part of the Tibetan Plateau.Mesospheric density profiles from 50 to 90 km were retrieved based on 205 nights of lidar observation,with a total of 1616hours of operation.We compared our lidar density measurements with SABER observations onboard TIMED satellite and MSIS-00 model data.The results showed that the annual mean density measured by lidar agreed well with SABER data,but both were lower than that of MSIS-00.All datasets exhibited dominant annual oscillation in the mesosphere.From 63 to 85 km,the annual amplitude of lidar density is larger than those of SABER and MSIS-00.PDD(Percentage of Density Difference)was calculated to investigate the mesospheric density climatology.The largest density variations of lidar,MSIS-00,and SABER occurred at around 72 km.Both lidar and SABER PDD reached their maximum in May,about one month earlier than the MSIS-00;while the minimum PDD appeared in late December for all datasets.展开更多
A sodium fluorescence Doppler lidar system has been developed to measure environmental parameters of the middle and upper atmosphere. The lidar system mainly comprises a transmitter system,receiver system,data acquisi...A sodium fluorescence Doppler lidar system has been developed to measure environmental parameters of the middle and upper atmosphere. The lidar system mainly comprises a transmitter system,receiver system,data acquisition and control system and data analysis system. A narrowband 589 nm laser is used to excite sodium atoms in the mesopause region. Excitation of the sodium atoms results in resonance fluorescence,which is collected by the receiver. The temperatures in the mesopause region(about 75-105 km) can be derived by analyzing the Doppler-broadened width of the sodium fluorescence. Observations were made with the lidar system,and the number density of sodium atoms and atmospheric temperature profiles were extracted from the observation data. Comparisons of the lidar temperatures and TIMED/SABER temperatures show good agreement,illustrating the reliability of the sodium fluorescence Doppler lidar measurements.展开更多
The first imaging observation experiment of the atmospheric gravity waves in the mesopause region with the all-sky OH Meinel band airglow CCD imager is made during 02:00 to 06:00 on January 5,2009,at Hancun (39.4°...The first imaging observation experiment of the atmospheric gravity waves in the mesopause region with the all-sky OH Meinel band airglow CCD imager is made during 02:00 to 06:00 on January 5,2009,at Hancun (39.4°N,116.6°E),Langfang,Hebei in China.Quasi-monochromatic gravity waves (QMGWs) are found clearly in the observation data.Case studies show that their horizontal wavelengths,horizontal phase velocities,azimuth angles of horizontal propagation directions and periods of three QMGW examples are about 12.3 km,41 m/s,327°,5 min;25 km,35 m/s,68°,12 min;and 10 km,48 m/s,341°,3.5 min respectively.展开更多
基金Supported by the National Key R and D Program of China(2018YFC1407301,2016YFC1400301)the National Natural Science Foundation of China(41127901)。
文摘From Aug.2013 to Oct.2015,a Rayleigh lidar has been used to study the middle atmosphere at Golmud(36.25°N,94.54°E),Qinghai,located in the northeastern part of the Tibetan Plateau.Mesospheric density profiles from 50 to 90 km were retrieved based on 205 nights of lidar observation,with a total of 1616hours of operation.We compared our lidar density measurements with SABER observations onboard TIMED satellite and MSIS-00 model data.The results showed that the annual mean density measured by lidar agreed well with SABER data,but both were lower than that of MSIS-00.All datasets exhibited dominant annual oscillation in the mesosphere.From 63 to 85 km,the annual amplitude of lidar density is larger than those of SABER and MSIS-00.PDD(Percentage of Density Difference)was calculated to investigate the mesospheric density climatology.The largest density variations of lidar,MSIS-00,and SABER occurred at around 72 km.Both lidar and SABER PDD reached their maximum in May,about one month earlier than the MSIS-00;while the minimum PDD appeared in late December for all datasets.
基金supported by the National Natural Science Foundation of China (40774087)
文摘A sodium fluorescence Doppler lidar system has been developed to measure environmental parameters of the middle and upper atmosphere. The lidar system mainly comprises a transmitter system,receiver system,data acquisition and control system and data analysis system. A narrowband 589 nm laser is used to excite sodium atoms in the mesopause region. Excitation of the sodium atoms results in resonance fluorescence,which is collected by the receiver. The temperatures in the mesopause region(about 75-105 km) can be derived by analyzing the Doppler-broadened width of the sodium fluorescence. Observations were made with the lidar system,and the number density of sodium atoms and atmospheric temperature profiles were extracted from the observation data. Comparisons of the lidar temperatures and TIMED/SABER temperatures show good agreement,illustrating the reliability of the sodium fluorescence Doppler lidar measurements.
基金supported by the National Natural Science Foundation of China (Grant No.40774087)
文摘The first imaging observation experiment of the atmospheric gravity waves in the mesopause region with the all-sky OH Meinel band airglow CCD imager is made during 02:00 to 06:00 on January 5,2009,at Hancun (39.4°N,116.6°E),Langfang,Hebei in China.Quasi-monochromatic gravity waves (QMGWs) are found clearly in the observation data.Case studies show that their horizontal wavelengths,horizontal phase velocities,azimuth angles of horizontal propagation directions and periods of three QMGW examples are about 12.3 km,41 m/s,327°,5 min;25 km,35 m/s,68°,12 min;and 10 km,48 m/s,341°,3.5 min respectively.
