中文摘要：

利用NCEP再分析资料，分析了中纬度地区的副热带高空急流各中心200hPa上的强度的季节、年际和年代际的变化。结果表明，高空急流各中心位置的季节变化形态不一致，表征强度的各特征参数的季节特征虽都呈现冬强夏弱的主要特征，各中心的变化特点在于：东亚中心的急流面积和风速都有较大的变化；非洲中心面积变化小，但风速变化较大；而北美中心急流面积变化较大，风速变化较小。也有各自不同的变化形态和季节转换特征，四季的各急流中心的变化均不一致。急流各不同中心的各季节的强度特征参数发生年际和年代际变化的时期虽不尽相同，但大致都存在6～8a的振荡周期。

英文摘要：

The seasonal, interannual and interdecadal variations of the intensity of different subtropical upper jet-stream centers at 200 hPa are analyzed by using the NCEP reanalysis data. The results show that the seasonal variations in locations and intensity of different centers are obviously different from each other. The change is characterized by the following： the area and the wind speed of the EAJ center are much more variable ; the variation in the area of the WJ center is small ,though its variation of the wind speed is big; the variation in the area of the AJ center is large, though its variation of the wind speed is small. The characteristic parameters which are used to describe the intensity of different centers indicate that they have respectively seasonal variations, though each center is strong in winter and weak in summer. Each season has its own annual trends. Though their interannual and interdecadal periods do not keep the same step with each other, they all have 6-8 years oscillation periods in a sense.