资源环境科技发展态势分析平台

The potential energy of gravity waves (GWs) per unit mass (E-p), at altitudes of 15-70km, has been examined from temperature profiles obtained by a Rayleigh/Raman lidar at Syowa Station (69 degrees S, 40 degrees E) from May 2011 to October 2013, with the exception of the summer months. The GWs with ground-based wave periods longer than 2h and vertical wavelengths between 1.8 and 16km were extracted from the temperature profiles. E-p was larger in winter than in spring and fall, although in 2012, at altitudes below 30km, E-p was larger in spring than in winter and fall. E-p increased with a mean scale height of 11.3km. E-p profiles showed a local maximum at an altitude of 20km and a minimum at 25km in almost every month, which has not been reported by previous studies observed by radiosondes. The values of E-p in October of 2012 were smaller at 35-60km and larger at 20-35km than those in October of 2011 and 2013. This difference in the E-p profile is most probably caused by different seasonal variations of zonal winds. The larger and smaller E-p values seem to be observed both below and above the altitude at which the zonal wind speed reached 0ms(-1). This result suggests that wind filtering of gravity waves with small phase speeds is significantly important in early spring.