The evolution of various nonlinear processes associated with the propagation of stationary planetary waves (SPW) during sudden stratospheric warmings (SSW) is studied from the troposphere up to the lower mesosphere levels. Based on data of the UK Met Office (UKMO), the spatiotemporal structure of the processes of planetary waves interaction with each other and with the mean flow, as well as wave activity, potential enstrophy flux divergence and advection, was analyzed. Such an analysis was performed for the 2008-2009 winter, when an SSW, accompanied by the splitting of the stratospheric polar vortex, was observed and for the 2018-2019 winter, when an SSW with the displacement of the stratospheric polar vortex was observed. The results show that these SSWs are succeeded by significant differences in the nonlinear processes under consideration. It is also demonstrated that during the SSW with the stratospheric polar vortex displacement the contribution of various processes to the balance of the disturbed potential enstrophy for SPWs with different zonal wavenumbers is comparable. In addition, during the SSW with the stratospheric polar vortex splitting, the exchange of waves with the mean flow makes the greatest contribution to the perturbed potential enstrophy balance.