On the Relationship between the Characteristics of the Annual Variations of the Virtual Height of the Ionospheric Sporadic E Layer with the Seasonal Rearrangements of the Stratomesospheric Circulation

Abstract—

Analysis of the temporal variations of the virtual heights of the sporadic E layer (hꞌE_S) determined from ionograms with increased accuracy (1 km) has revealed the following features of annual variations in the mid-latitudes of the Northern Hemisphere. It has been found that the intra-seasonal average values of hꞌE_S are higher in the winter than in summer. The range of intra-seasonal variations, which, along with noise, contain variations with periods from several days to several tens of days, is also larger in winter than in summer. It should be noted that the changes in seasonal modes occur rather quickly. This, as well as the increase in the amplitudes of variations with periods characteristic of planetary waves in winter, allows us to make an assumption about the connection of seasonal transitions in the behavior of hꞌE_S with the spring and autumn rearrangements of the circulation in the middle atmosphere. In order to verify this assumption, the results of rocket measurements of the zonal wind speed at 20–80-km altitudes above Volgograd (48°68′ N, 44°35′ E) are compared to the data from Poitiers ionospheric station (46°6′ N, 0°3′ E) in 1984–1989. It has been found that in 1984–1988 the timing of the spring change of seasonal modes of the behavior of hꞌE_S and the timing of the rearrangement of the stratomeasospheric circulation from west to east coincided, and the transition in the ionosphere slightly preceded the rearrangement in the middle atmosphere only in 1989. In autumn, the change in seasonal modes of the behavior of hꞌE_S in 1984–1989 was always delayed relative to the onset of the zonal wind reversal in the stratomesosphere by an almost fixed time interval of approximately 2 months.