地形对大尺度流型年际变化的影响

THE INFLUENCE OF GEOGRAPHY ON INTERANNUAL VARIATION OF LARGESCALE FLOW PATTERNS

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.