Acoustic-gravity waves (AGW) are hybrid atmospheric oscillations in which both compressibility and buoyancy act as effective restoring forces. Combining the characteristics of acoustic waves with those of internal gravity waves, AGWs are an important mechanism for redistributing energy, momentum, and variability throughout the atmosphere. They arise from disturbances in atmospheric equilibrium resulting from a wide range of dynamic and impulsive processes, including deep convection, frontal activity, orographic forcing, volcanic eruptions, seismic events, and meteoroid impacts such as the Chelyabinsk flash. Comparable excitation mechanisms operate in the upper atmosphere and ionosphere, where geomagnetic disturbances, auroral heating, and shear in the background wind field may additionally contribute to AGW formation.
Following their excitation, AGWs are capable of propagating horizontally over long distances and vertically from the troposphere into the stratosphere, mesosphere, thermosphere and ionosphere. Their evolution is governed by ambient stratification, the Brunt–Vaisala frequency and spatial variations in atmospheric winds. As AGWs ascend into regions of progressively lower density, their amplitudes increase and they may undergo nonlinear transformation, ultimately dissipating and depositing energy and momentum into the background atmosphere. In the ionospheric domain, AGWs modulate electron density and may induce travelling ionospheric disturbances, thereby contributing to the coupling between atmospheric layers and influencing space–weather dynamics.Consequently, AGWs represent a fundamental component of vertical coupling within the geospace environment, mediating interactions between the lower atmosphere and near-space regions, and serving as key drivers of mesoscale and thermospheric–ionospheric variability.
Our group deals with observations of astrophysical sources (pulsars, quasars, SNRs) of radiation and analysis of the ionosphere’s impact on flux variability over time and across frequencies. The results of the observations are verified by models of radio wave propagation through the ionosphere disturbed by the presence of AGW.