本文的第二部分主要讨论非线性波速公式。由于非线性波动的波速公式与波形有关,为此文中引入了反映波形的无量纲量M。我们发现M可以表征波动非线性程度的大小,此即为M判据。文中还给出了非线性Rossby波与非线性重力惯性波的波速公式,对前者振幅大的波动相速度小,而对后者则相反。此外,文中还讨论了在求非线性波动的近似解时应用Taylor展开时所必须注意的问题。 The second part of this paper mainly discusses the nonlinear wave velocity formula. Since the wave velocity of non-linear fluctuations is related to the waveform, a dimensionless quantity M that reflects the wave is introduced in this paper. We find that M can characterize the degree of non-linear fluctuations in the size, which is M criterion. The wave velocity formulas of nonlinear Rossby wave and non-linear gravitational inertial wave are also given in this paper. For the former, the amplitude of the fluctuating phase with large amplitude is small, while the latter is opposite. In addition, the paper also discusses the problems that must be noticed when applying Taylor expansion in finding approximate solutions of nonlinear fluctuations.