Simulation of Internal Gravity Wave Propagation Due to Sudden Stratospheric Warming

Abstract

The results of modeling the effect of stratospheric internal gravity waves (IGWs) excited in the region of sudden stratospheric warming (SSP) on the state of the upper atmosphere are presented. The numerical experiment used a two-dimensional model of atmospheric wave propagation including the dissipative and nonlinear processes accompanying the wave propagation. As a perturbation source, perturbations of temperature and density in a localized region at stratospheric altitudes during the SSW were considered. The amplitude and frequency of the perturbation source were evaluated from the results of observations and IGW theory. The results of numerical calculations showed that the heat source localized in the stratosphere excites IGWs with periods of up to several hours, which reach the thermospheric altitudes within a few hours. The maximum relative perturbations created by these waves relative to the unperturbed conditions were noted at altitudes of 100–200 km and at distances of up to ~1000 km from the source center.