Аскаплоты советских станций за 1980 год : (оперативно-информационный материал) / Акад. наук СССР, Кол. фил. им. С. М. Кирова, Поляр. геофиз. ин-т. – Апатиты : Кольский филиал АН СССР, 1984. – 78 с.

13 Рогsolar activity the situation is similar though in autumnal equinox a deviation from the smooth semi-annual variation ia observed. Seasonal auroral variations can be also presented as a semi-annual wave, for the first consideration, though with another month delay relatively to magnetic activity and Wolf numerals. Figure 4b presents seasonal variations of the same parameters averaged for 1972-1980. The solid horizontal line corresponds to averaged values of all para­ meters, Seasonal variations given in Figure 4b are displayed very poorly though the period of averaging was large and might have revealed the semi-annual variation presented in Figure 4a, Seasonal variation manifested itself best of all through magnetic activity where both equinox,maxima are seen though they have different amplitudes. Variations of auroral activity more resemble the annual wave with the maximum in winter» Cycle variations of the same parameters for 1972-19SO are given in Figure 5, The 11-year cycle of Wolf numerals and 4-5 year cycle of magnetic activity are distinctly seen. Aurora variations better coincide with variations of Wolf numerals.