ИСТИНА

For the period November-December 1990 and March 1991 latitudinal profiles of vertical electron content were obtained using Doppler reception of navigational satellite coherent signals at spaced points which have been placed in auroral and subauroral zones. Data of ionospheric and magnetometric stations located near by the auroral receiving point were used for interpretation of development processes of ionospheric structures. For example, very often formation of the main ionospheric trough is similar in the considering seasons: an east electrojet accelerates slump of F-layer critical frequency after noon and creation of a southern wall of a trough, but a west electrojet affects on dynamics of the formed trough. The process has some peculiarities in the seasons which are depended, in particular, on differences in illumination of the ionosphere with solar radiation.