Space-time variations of equatorial Kelvin wave activity around the tropical tropopause region

利用欧洲欧洲中期天气预测中心（ECMWF）再分析数据集（ERA-40）对热带热带结核病地区的温度和区域风进行了评估。该光谱分析被用于在区域风数据的区域波数和频率域中进行计算。发现两个光谱峰值：一个在频率为0.035-0.25[1/天]和Kelvin波的区域中，另一个在频率为0.011-0.035[1/天]和区域内振荡（ISO）的区域中。基于这些频率波群域的网格数据被重构以代表Kelvin Wave和ISO活动，以及这些变化是从网格数据中计算的，以查看Kelvin Wave和ISO的空间-时间变化。ISO的活动显然与东方传播活动有关，而Kelvin Wave的活动在60 ° E （西印度海洋）的一年内组织起来。我们从重建的区域风数据中选择了Kelvin波事件，达到-2.938 [m/s]，以查看Kelvin波的生命周期。Kelvin波在60 ° E范围内具有高活动性，在30 ° W至60 ° E范围内，在60 ° E至150 ° E范围内消失。通过对Kelvin波事件的复合分析，我们发现Kelvin波生成与conv性事件封闭了耦合，因此Kelvin波生成的区域与西太平洋地区的活跃的conv性区域并不正确。

Space-time variations of the temperature and the zonal wind around the tropical tropopause region are examined using the European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis data set (ERA-40). The spectral analysis is performed to calculate power spectra in the zonal wavenumber and frequency domain for the zonal wind data. Two spectral peaks are found : one is in a region with frequency 0.035-0.25[1/day] and zonal wavenumber 1-10 for the Kelvin wave, and the other in a region with frequency 0.011-0.035[1/day] and zonal wavenumber 1-10 for the Intraseasonal Oscillation (ISO). On the basis of these frequency-wavenumber domains the grid data are reconstructed to represent Kelvin wave and the ISO activities, and the variances are calculated from the gridded data to see space-time variations of the Kelvin wave and the ISO. The ISO activity is clearly related to the eastward propagating convections, though the Kelvin wave activity is organized around 60゜E (the western Indian Ocean) throughout the year. We selected Kelvin wave events from the reconstructed zonal wind data with a threshold of -2.938 [m/s] to see the life cycle of the Kelvin waves. Kelvin waves with high activity around 60゜E begin mostly around 30゜W to 60゜E and disappear around 60゜E to 150゜E. By performing the composite analysis for the Kelvin wave events we found that the Kelvin wave generation is closely coupled with the convective event, though the area of the Kelvin wave generation does not correspond to the active convective area such as in the western Pacific.