On Quasi-Two-Week (10-20 Day) Oscillation in the Tropical Atmosphere
热带大气中的准双周（10—20天）振荡

Based on the 10-20 day band-pass filtered data which are computed from ECMWF global dais (1981-1987), the 10-20 day (quasi-two-week) atmospheric oscillation in the tropics is studied systematically in this paper. The oscillation includes that in the distribution and evolution of kinetic energy,the structure and propagation feature of this kind of low-frequency and so on. It is shown that the 10-20 day osCillation is another important low-frequency system in the tropical atthosphere. Its kinetic energy is even stronger than 30-60 day oscillation. Its structllre and activity is different from the 30-60day oscillation. For instance, the 10-20 day oscillation in the tropical atmosphere is dominated by the perturbances of the zonal wavenumber 2-4. Its vertical structure mainly displays barotropic feature. It mainly propagates westwards. The meridional wind component and zonal wind component are same important. Therefore, the study focused on the 10-20 day oscillation in the tropical atmoSPhere is very necessary.