Coupling of the Wave-like Disturbances in Winter Ionosphere and Stratospheric Dynamics

Abstract

Based on data from ionosondes and the ECMWF ERA-Interim reanalysis, we investigated the causes of medium-scale wave-like disturbances in winter ionosphere caused by the atmospheric waves arising in high-speed jet streams in the stratosphere and mesosphere. Perturbations of the ionosphere are considered as the maximum electron density N m F2 deviations from the daily averages. According to the UARS mission measurements in 1991–1992, quantitative estimates were performed of the energy flux and air mass generated in the summer tropical stratosphere/mesosphere and flowing as jet streams to the polar region. Medium-scale wave-like movements in the stratosphere and lower mesosphere occur in the autumn–winter time (November–February) as a consequence of the shear-layer instability in a flat-layered jet stream. Partially, the disturbances’ spectrum is amplified when a wave propagates against the flux. The disturbances are transmitted to the heights of the lower mesosphere and higher in the form of internal gravity waves, appearing in the ionosphere as travelling ionospheric disturbances. According to data from the Irkutsk and Norilsk ionosondes, activity of the medium-scale wave-like disturbances coming from the stratosphere and mesosphere is comparable to that of geomagnetic disturbances in the ionosphere.