DYNAMICAL STUDIES ON THE FORMATION OF PLANETARY WAVES.

在目前的研究中，本文利用大气环流模式模拟和气象再分析资料，沿着研究了平流层定常行星波和行星际波的形成机制，并利用美国国家环境预报中心（NCEP）/美国国家大气研究中心（NCAR）的资料，研究了平流层行星际波5天波的年际变化。再分析数据发现平流层5日波振幅存在准两年的变化。这种准两年变化与赤道平流层准两年振荡（QBO）相关的纬向风变化密切相关：QBO的东风切变相的5天振幅大于西风切变相的5天振幅，而北极涛动的空间分布在北极和中纬度之间呈跷跷板状，关于大气环流的年际变率，人们已经进行了广泛的讨论。AO被认为与定常行星波的变化密切相关。利用NCEP/NCAR再分析资料，研究了AO、北大西洋涛动（NAO）和太平洋及北美涛动（PNA）型之间的关系。结果发现，观测到的AO几乎是明显的，两个几乎独立的跷跷板，即NAO和PNA振荡模式，从观测数据重建明显再现AO。

Throughout the current study, we have investigated the formation mechanism of stationary and traveling planetary waves on the basis of meteorological reanalysis data along with general circulation model simulations.As regards the traveling planetary waves) interannual variability of the 5-day wave in the stratosphere has been examined by the use of the National Center for Environmental Prediction (NCEP)/ National Center for Atmospheric research (NCAR) reanalysis data. We have found the quasi-biennial variation of the 5-day wave amplitude in the stratosphere. This quasi-biennial variation is closely related to the zonal wind variation associated with the quasi-biennial oscillation (QBO) in the equatorial stratosphere : The 5-day wave amplitude during the easterly shear phase of the QBO is larger than that during the westerly shear phase.On the other hand, the Arctic Oscillation, whose spatial pattern shows a seesaw between the Arctic and mid-latitudes, has been widely discussed concerning the interannual variability of the general circulation. The AO is considered to be closely related to the variability of stationary planetary waves. We have investigated the relationship among the AO, the North Atlantic Oscillation (NAO) and the Pacific and North American (PNA) oscillation pattern on the basis of the NCEP/NCAR reanalysis data. As a result, we have found that the observed AO is almost apparent and two almost independent seesaws, i.e. the NAO and the PNA oscillation pattern, reconstructed from the observed data apparently reproduce the AO.