本文通过对正压涡度方程的截谱形式进行几十组长度为30年的数值积分,研究了在年变周期和非年变周期两种热力强迫作用下,地形对所激发的大尺度流型年际变化的影响。发现在一定参数域,地形的引人可以:(1)使大气内部动力过程激发流型的年际振动;(2)使流型年际振动的振幅显著减小,周期变长;(3)抑制流型年际变化振幅随热力参数渐变而突变的幅度。

In this paper,it is investigated that the influence of geography on interannual variation of large-scale flow patterns arised from external interannual thermal forcing and internal dynamical processes by means of low-order spectral model of barotropic vorticity equation.More than 60 numerical experiments whose integration time is larger than 30 model years are performed for every case that orographic factor is introduced into the model or not.When orographic factor is considered in the model,in certain parametric region,the computed results show that (1) the interannual variation of large-scale flow pattern can be arised from internal dynamical processes;(2) the amplitudes of flow patterns become small obviously and their periodes become long;(3) the range of amplitude-jump of flow patterns interannual variation is decreased along with gradual changes of thermal forcing parameters.