Numerical modelling of relative contribution of planetary waves to the atmospheric circulation

Abstract

Abstract. Using the general circulation model of the middle and upper atmosphere (MUAM), a number of numerical scenarios were implemented to study the impact of individual planetary waves (PWs) on the global atmospheric circulation, including zonal wind, temperature, and residual meridional circulation (RMC). The calculations were performed for the winter conditions of the Northern Hemisphere (January–February). We show the contribution to the formation of the dynamic and temperature regimes of the MUAM made by equatorial Kelvin waves propagating to the east, as well as atmospheric normal modes (NMs) with periods from 4 to 16 d. In particular, it is demonstrated that the impact of a 5 d PW and an ultra-fast Kelvin wave (UFKW) can change the speed of circulation flows by up to 6 % in the areas of their amplitude maxima. At the same time, this effect can be significantly enhanced in certain periods of time. The presented research results are important for a deeper understanding of the mechanisms of large-scale atmospheric interactions. Despite the obviousness and simplicity of the problem, such work has not been carried out yet.