Аскаплоты советских станций за 1983 год : (оперативно-информационный материал) / Акад. наук СССР, Кол. фил. им. С. М. Кирова, Поляр. геофиз. ин-т. – Апатиты : Кольский филиал АН СССР, 1990.

12 1 ball were observed in the north and in the zenith, no clouds in tha south. XIV: the sky is cloudless, no auroras, moon lighting. XV: the situation is similar, but the ascafilms turned out to -be of poor quality Ъесаизе of some technical reasons (bad development of this part of the film, breaks of automatic work). The described example presents all the situations one can encounter in ascaplots. Auroral PA index. The index of auroral activity calculated with the help of ascaplots was suggested in /9/. It equals to: PA = N К (Qhy\1 ), where И is the number of blackened squares within the time interval, and К is the coefficient depending on the station's latitude. The connection between N and the auroral magnetic index AL for midnight hours was determines in /9/ from ascaplots of 35 stations during IGY /1,2/. Using these data the dependence of the К-coefficient on the latitude was obtained for two longitudinal intervals. This allows to agjust the data of the stations located at different latitudes to a common value. Since the K-index was calculated for midnight auroras, the PA index is estimated only for a 4-hour interval in the region of the local geomagnetic midnight. AL scales are chosen so that the corresponding values of the PA index be linearly proportional to the energy of auroral electrons of the auroral oval /9/. This provides any arithmetic operations with the PA index, such os averaging, without loss of physical content. Table 2 includes PA values for each day of 1983. For a separate station PA can be determined only for a 4-hour interval which may not coincide with the maximum of auroral activity. That Is why table 2 presents PA values obtained by averaging the indices of all the stations operated during that day. The numeral in brackets following every index gives the number of operating stations the data of which were averaged in calculating the index. The gap in. the Table denotes absence of observations during that day at local midnight. Auroras registered at cloudy conditions were taken into account in calculations of the PA index. This change increases the representativity and statistical veracity of the data, but on the other hand, this leads to a rise of the PA average value. Auroral activity in 1983. Figure 3 presents diurnal variations of the PA index and I Kp for each day in 1983. The dashes link the points of gaps of observations. Fig.3 contains numerous gaps since few stations operated during 1983 and this is eapeoially noticeable in May-August when only one station operated in the southern hemisphere. Definition of the PA by one station is poorly representative that causes a very bad coincidence with magnetic activity. For the year of 1983 82 per cent of the events were defined by one station, whereas 16 and 2 per cent of the events were defined by two and three stations, respectively. Thus Figure 3 can be used only for a quick look selection of periods and rough evaluation of auroral activity. When averaged the connection between auroral and magnetic activity becomes significantly better. Figure 4 presents variations of the PA and £ Kp for the winter months in the northern hemisphere averaged for 5 days. Note that the PA data were smoothed out according to the trapeaium formula. As seen from the Figure a distinct, but not very good, interrelation between these phenomena is observed. The correlation coefficient is equal to 0.74 and 0.51 for the first and the second periods, respectively. This is better