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

4 IONOSPHERIC PHENOMENA - 7 3 The IMS - Observational Data of Polar Geophysical Institute USSR Academy of Sciences Editor B.E.Brunalli Apatity - 1979 The volume contains the results of Ionospheric observations of the Polar iieophysical Institute and continues the series of publications started in 1970. Since 1977 the data are published in two volumes of "Auroral Phenomena" /1/ with the re­ sults of geomagnetic and auroral observations and "Ionospheric Phenomena" / 2 / with the data or vertical sounding,absorption measurements,baloon and radar observations. The ionosphere sounding at Murmansk is carried out by means of AlS ionosonde with frequency range of 1-20MHz,sweep time of 3 0 s.,height range- 1 5 0 0 km. The ionograne are received eve 17 15 min. The information on ionospheric sounding is presented in form of f-plot with standard /5/ designations additionally explained in the Russian text. The absorption measurements at st.Loparskaya were carried out by means of stan­ dard riometer with frequency of 32MHz,bandwidth of 9kHz, time integration 30s,antenna main lobe 50x60° directed towards the Polar Star. The base line values were derived on quiet days records monthly. On the graph the absorption variation is given,the days with complete absorption absence were excluded. The radioaurora observations at at. Esaoila were carried out by means of radar on f=88MHz with bandwidth of 270 kHz, power in pulse - 60kW, range of I200km,the period of antenna rotation - 40-90s. The time of radioaurora occurence ia given in the tables. The geographical and corrected geomagnetic coordinates /4/ of the stations are given in Table I. Universal time is used everywhere. The behaviour of ionosphere depends on the presence of disturbances. Their dis­ tribution over the year according to geomagnetic data is considered in /3/. In the most compact form the distribution is presented at Calendar,fig.I,where the activity for each hour of the year ia given according to ionospheric,geomagnetic and auroral observations. It із evident that three types of activity estimation agree rather well and that the activity undergoes diurnal variation with minimum in daytime, middle part of each row. The decrease of activity in daytime is connected with grow­ ing of importance of stable solar UV radiation and with displacement of auroral oval towards high latitudes. Quantitative estimation of geomagnetic activity for each day can be obtained from daily mean value of hourly range rH presented at Table 2. From the monthly mean values it ia seen that the activity in the first half of the year is higher than in the second half. An exact maximum is also seen near spring equinox, Apri 1 - M a y ,the autumn maximum in contrary is absent,the activity in October is unusua­ lly low. The activity increasing usually covers several days and is the highest in the beginning of the active period. Days in Table 2 when rH value essentially exceeds the value of the previous day or when magnetogram becomes more complicated are marked. These marked days can be arranged in four sequences presented at Table 3 . The posi­ tion of two of them at the Bartel's Calendar is approximately constant,whereas the other two shift,their period of repetition exceeds 27 or even 28 days. If the pointed sequences are connected with the Sun active regions,they are located at different he- liogrRphic latitudes. Several K A events were observed during the year. Their rise is easily revealed from the given graph of absorption variation. PCA is accompanied by high values of n baorption,its gradual change with maximum at daytiaie and decreasing towards night.