Ионосферные явления-78: материалы наблюдений Поляр. геофиз. ин-та по проекту Междунар. исслед. магнитосферы за 1978г. (оперативно-информационный материал). Апатиты, 1979.

slower than increases in morning hours and hence the evening values of fo?2 exceeds the value before noon. The appearance of disturbances leads to decreasing of elect­ ron density at afternoon hours towards its value in morning hours,symmetrio rela­ tively noon and the difference between morning and evening hours vanishes. At night hours of the summer season the disturbances reduces the electron density and the diurnal variation appears or increases, the nighttime values of foF2 decreases and the difference between day and night values of electron density grows. Ihe value of electron density in daytime depends on the activity in the previous night. After disturbed night the midday foF2 values are lower than after quiet night. In the Russian text after general description of the behaviour of ionosphere the unalysis of ionospheric variation and geomagnetic activity during every month is given.