Аскаплоты советских станций за 1975 год : (оперативно-информационный материал) / Акад. наук СССР, Кол. фил. им. С. М. Кирова, Поляр. геофиз. ин-т. – Апатиты : Кольский филиал АН СССР, 1988.

12 observed. PA seasonal variations practically follow magnetic activity variations but are weakly displayed. Is should be mentioned that solar activity expressed in monthly averaged Wolf numbers changes antiphased to auroral and magnetic activity. Pig.5 contains seasonal variations of the same parameters averaged for 1972-1975 and are constructed according to the same technique. Absence of remarkable variations is a typical feature of Wolf numbers and auroral activity. Only magnetic activity has seasonal variations with equinoxial maxima and minima in winter and in summer. Pig.5 presents differences between auroral magnetic and solar activity in 1975 and their mean values. Since there are practically no seasonal variations of polar auroras and Wolf numbers then the differences between variations recur to seasonal variations of these parameters for 1975. This year coincides with the minimum of solar activity and the differential curve for W is located in the region of negative values. Since for magnetic activity the amplitude of seasonal variations for 1975 is higher than for the mean values, thus their difference changes, in general, are similar to seasonal variations in 1975. Cycle variations for the period 1972-1975 are recorded in the askaplot issue for 1980 /6/.