Abstract: 300hpa meridional wind data from a GCM experiment in GFDL were analyzed to document the characteristics of wave packets in GCM data. Utilizing the one-point lag correlation and the complex demodulation, authors computed some characteristic variables of wave packets. Results show that the wavelength is a few thousand kilometers. The phase speed is about 10m/s, and the group speed is about 2～3 times of the phase speed. It also shows that the downstream development of baroclinic wave in GCM data is more popular than that in the observational data, and that wave packets in GCM data are more coherent.

Key words: baroclinic wave packets, GCM, time-lagged one-point correlation, downstream development, storm tracks

摘要： 利用时间滞后相关和波包的复分解方法，分析了GCM模式资料300hpa的经向风扰动。计算了波包的波长、波数、相速和群速等物理量，揭示了波包的基本动力学特征。斜压波包的波长为数千公里，相速为10m/s左右。波包包络的传播速度为相速的2～3倍，下游发展仍是斜压波包的主要特征。同时，斜压波包在传播过程中显示出较好的相干性，即波包的包络能较长时间内维持其形状不变。详细分析了波包性质的季节变化和南北半球的差异，并将模式资料的结果与实测资料做了比较。

关键词: 斜压波包, GCM模式, 一点滞后相关, 下游发展, 风暴轴