摘要
本文研究了在各种定常基本状态下大气对位于热带及中纬度地区的定常强迫源的响应。进一步证实了东风基本气流将限制热带扰动向中高纬度的传播,从而也抑制了两半球的相互作用;西风基本气流则有利于热带波动向中纬度传播,有利于中纬度扰动通过热带向另一半球传播。赤道地区基本气流随经度的变化对罗斯贝波的传播也有重大影响,波动能量将在基本气流辐合的地区累积并向中纬度发射。因此赤道西风辐合最大的地区就是热带与中纬度相互作用以及两半球相互作用最明显的地区。应用实测风场作基本气流所进行的实验表明,冬季与夏季热带波动的传播特征,两半球相互作用的状况均有明显差异。
In this study the response of atmosphere to the stationary forcing for various basic stateshave been examined.It is further confirmed that easterly basic flow traps the waves in the trop-ics,hence the interaction of waves between two hemispheres is restricted, whereas the westerlybasic flow is favorable to the wave propagation from the tropics to middle latitudes as well asfrom one hemisphere to the other.The influence of the zonal variation of the tropical basic flowon the propagation of equatorial Rossby waves is significant.The wave energy accumulates in theconvergence region of basic zonal wind and emanates from there to middle la(?)tudes.Therefore,the region of equatorial westerlies with a maximum negative stretching acts as a key region forthe active interactions between the tropics and middle latitudes as well as between two hemi-spheres.In the experiments with the observational data as the basic state ,it is found that the charac-teristics of the tropical wave propagation and the behavior of interaction between the hemispheresin winter are very different from those in summer.
基金
国家气象局季风科研基金
