旋转大气中有限振幅扰动波包与基本气流的非线性共振相互作用

NONLINEAR RESONANCE INTERACTION BETWEEN A FINITE-AMPLITUDE DISTURBANCE WAVE ENSEMBLE AND THE ZONAL MEAN FLOW INROTATING BAROTROPIC ATMOSPHERE

中文摘要:

      本文应用多重尺度法研究了在旋转球面上正压大气中有限振幅扰动波包与纬向基本气流的非线性共振相互作用.首先,导出了同时包含色散效应和耗散效应的三波共振非线性耦合方程.然后,在零耗散极限和无规相位近似下,求得了不同模态波包的非线性共振耦合方程.并着重讨论了有限振幅扰动波包与纬向基本气流之间的能量输运过程.结果表明,在旋转球面上正压大气中的有限振幅扰动波包通过非线性共振相互作用能够激发出纬向基本气流,而且其能量最终都要输运给纬向基本气流,直至大气运动成为完全的带状环流为止.从而阐明了非线性共振相互作用是大气旋转适应过程的重要物理机制.

英文摘要:

      The nonlinear resonance interaction between a finite-amplitude disturbance wave ensemble and the zonal mean flow in rotating barotropic atmosphere is studied by multiple-time-scale analysis. The nonlinear triad coupling equation with dispersion and dissipation is given. The nonlinear coupling equation between wave ensembles with three modes is derived by the random phase approximation and the zero dissipation limit. The energy transfer process between finite-amplitude disturbance wave ensemble and zonal mean flow is described. The solution of coupling equation reveals that the finite-amplitude disturbancel wav心ensemble can be completely transferred into the zonal mean flow by nonlinear resonance interaction in rotating barotropic atmosphere. The energy transfer process would continue until the motion become pure zonal flow. It also reveals that the nonlinear resonance interaction is an important mechanism for the rotative adjustment.