热带大气中的准双周（10—20天）振荡

基于欧洲中期天气预报中心（ECMWF）的资料（1981—1988），本文对全球热带大气中的10—20天（准双周）振荡进行了比较系统的研究，包括其动能的分布及演变。扰动的结构和传播特征等。资料分析充分表明，热带大气10—20天振荡是热带大气中另一重要低频系统，其动能比30—60天振荡还要大，而其结构和活动又同30—60天振荡很不一样。例如热带大气10—20天振荡主要表现为纬向波数2—4；垂直结构以正压特征更显著；主要表现为向西传播；其经向风分量与纬向风分量同等重要。因此，对热带大气10—20天振荡值得更多注

On Quasi-Two-Week (10-20 Day) Oscillation in the Tropical Atmosphere

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.