N(h) profiles from ground and “Interkosmos-19” satellite data

During the years of high solar activity (1979–1980) simultaneous soundings of the ionosphere were made by the Bulgarian ground stations at Sofia and Michurin and by the satellite Interkosmos 19. The N(h) profiles for the ground stations were computed in association with IZMIRAN, Moscow and those for the satellite by SIB-IZMIRAN.During some of the satellite transit orbits the electron densities at the maximum of the F2 layer coincide precisely with those obtained from ground ionograms. In other cases differences were observed, perhaps because of the differences in time; the ionospheric stations at Sofia and Michurin worked on the ordinary 15-minute regime.