强迫二维Rossby波传播特征的数值试验

NUMERICAL EXPERIMENTS OF PROPAGATION CHARACTERS OF FORCED TWO DIMENSION ROSSBY WAVE

Bjerknes提出了大气对外界强迫响应的概念。大量研究已证明这一遥响应机制的存在,且大气对强迫源的遥响应及其低频活动的共同特征都表现为类似大圆路径的波列,Hoskins的理论研究揭示了这现象的实质,他把叶笃正所提出的Rossby波的频散理论推广到球面上。黄荣辉曾利用波折射指数平方与EP通量系统地研究了北半球冬夏准定常行星波的传播规律。邹晓蕾、叶笃正、吴国雄提出了中高纬的相关链、定常地形波链,并指出北美与东亚相关型的差异与两区域地形准定常波在不同纬向流中传播的差异有关。观测分析亦表明,青藏高原是大气低频振荡的强迫源,且在此区域可产生向北、向南或向东、向西传播的波列。

Factors (topograph structure, basic flow) affecting ray characters of two dimensional Rossby wave are examined in this paper by numerical experiments. The numerical expriment results show that:(1)under conditions of west basic flows and ideal topography of half ellipsoid,there is a wavetrain with a parabolic route in the east of the topography; (2)wavetrains of vertical motion disturbance may propagate southward;(3)under conditions of the real topography and westerlies,the wavetrain path shows a sine wave,and vorticity deviations forced by zonal sea-land thermal differences also show a sine wave pattern.