By using the Fourier method to solve the barotropic and nondivergent vor-ticity equation, the effect produced by the middle or low latitude disturbance to the flow field at the low or middle latitude is investigated.

• 用付里叶方法求解正压无辐散涡度方程,把初始扰动分别加在中纬或低纬,求得这些扰动在低纬或中纬度产生的作用。