Авроральные явления - 74 : материалы наблюдений Полярного геофизического института за 1974 г. : [сборник] / Акад. наук СССР, Кол. фил. им. С. М. Кирова, Поляр. геофиз. ин-т ; [отв. ред. Б. Е. Брюнелли]. - Апатиты : Кольский филиал АН СССР, 1977.

5 between 22-nd and 25-th days during second six months. In the middle of the year (rotation 1927) the first quiet period is interrupted by severe storm. The reccurent periods of increased activity over 1974 are given in Table I. The sequence A which ia traced through the whole year can be considered as a continuation of the sequence of the last months of 1973 /8/. The sequence ia displaced as soiue activity increasing over rather high background in the beginning of the year. Quiet intervals appear before it during second six months. The sequence Вappearing after quiet periods is marked in the second half of the 1973* The sequence 0 of Table 1 which also traced through the whole year is continuation of B-Bequence of 1973- The disturbances of the C-sequence in the first half of ch« year appear after the pronounced decreasing of the activity and are commonly accompanied by the sudden commencements, development of the , DH-variations (x’ing current.), well pronounced variation of AU-index, i.e. by the development of the total current system. The disturbances of the A-sequence in the first half of the year are not accompanied by the development of the ring and eastern currents: DE and All are small. The behavior is changed in the second six months, the disturbances of the А-sequence appear after the quiet conditions and are accompanied by all the storm features, as the disturbances of the O-sequence become leas significant. A- and С-sequences are the main sequences for 1974. Additional less pronounced sequences Вand D are given also in Table 1. All mentioned sequences are put at the map of the sector structure of the solar wind in accordance with /9/ (Fig.2). It is seen that the main A- and C- sequences are at the boundary between the main sectors* A-sequence is accompanied by the change of the sign from to "+" (from "towards" to "away"). The 0- eequence is accompanied by the reversal change of the sign. The B~ and D-sequences are accompanied by the temporary changes of the sign of the field. The character of the really observed disturbances is determined by the local time. It can be considered that the above described changes influence on the daily variation changing its amplitude. The disturbances at Loparskaya are observed as positive bays in the evening, negative bays accompanied by the AA-absorption at night and geomagnetic pulsations and smooth changing absorption - in the morning. The daily variation of the activity is given in Pig.3s (a) - the disturbances in geomagnetic field, (b) - ionosphere and (c) - aurora. The level of activity is taken in accordance with calendar (Fig.1). The variations of the sunspot numbers and A-index are given in the figure also. The equinox maxima are typical for the seasonal variation of the geomagnetic activity. The seasonal variation of the ionospheric activity has the rather email increasing by winter and is pronounced weakly. The daily variations of the different activity manifestations are given in Fig. H. Graph is based on the same data as Jig.3 (Calendar, Fig.1). The geomagnetic activity maximum ia observed at night. The ionospheric activity increases also at night, the additional activity maximum is seen in the winters morning. The description and the analysis of the disturbances over each month are given in Russian text.