Abstract:

Abstract: The statistical characteristics of inertia gravity waves in the lower stratosphere (21～28 km) over Kunming are studied based on the high vertical resolution L-band radiosonde data in the summer (June to August) of 2008 from Kunming sounding station. The results show that: 1) The vertical wavelengths are mainly in the range of 3.5～4 km, with an average of about 3.53 km. The horizontal wavelengths are mainly distributed between 250～1250 km, with a mean value of about 714 km. The ratio of the mean horizontal to vertical wavelength is about 200:1. 2) The intrinsic frequency is mainly concentrated in 1 ～2.5 , with an average of about 1.7 , equivalent to an intrinsic period of 17 hours or so. 3) The gravity wave energies are mostly propagating upward in the vertical direction with an occurrence of 86 %. The mean horizontal propagation directions of the gravity waves are mainly eastward, northward, southwestward, southward, and southeastward. 4) The vertical intrinsic phase speed is dominated by -0.1～0 m/s, with a mean value of about -0.06 m/s. The horizontal intrinsic phase speed mainly ranges from 10～20 m/s, with a mean value of about 14.5 m/s.