GCM模式中斜压波包的动力学特征  

Characteristics of Barolicnic Wave Packets in GCM Data

作　　者：汪名怀[1] 谭本馗[1] 

机构地区：[1]北京大学物理学院大气科学系,北京100871

出　　处：《北京大学学报（自然科学版）》2003年第1期40-50,共11页Acta Scientiarum Naturalium Universitatis Pekinensis

基　　金：国家自然科学基金 (49875 0 14); 973重大基础研究项目--我国重大天气灾害的机理;预测理论研究 (G19980 40 90 2 )资助项目

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 30 0hpa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。hPa meridional wind data from a GCM experiment run at GFDL of Princeton University was analyzed to document the characteristics of the baroclinic wave packets in GCM data. By use of the one-point lag correlation and the complex demodulation methods, the wavelength, wavenumber, phase velocity and the group velocity of the wave packets were computed. It is found that the typical wavelengths are around 3?000～6?000?km, the phase velocity is about 10?m/s and the group velocity is about 2～3 times of the phase velocity. It is also found that the downstream development of the baroclinic waves in GCM data is more common than in the observations, and that the wave packets in GCM model are more coherent than in the observations, i.e., the envelopes of the wave packets in model can remain unchanged for a longer period of time. The seasonal variations of the wave packets and the difference between the wave packets in the northern hemisphere and in the southern hemisphere are analyzed in detail. Finally the wave packets in models are compared with wave packets in the observations.

关 键 词：动力学特征 斜压波包 GCM模式 时间滞后相关 下游发展 风暴轴 天气系统 

分 类 号：P433.2[天文地球—大气科学及气象学]