Ионосферные явления-79: материалы наблюдений Поляр. геофиз. ин-та по проекту Междунар. исслед. магнитосферы за 1979г. (оперативно-информационный материал). Апатиты, 1983.

4 IONOSPHERIC PHENOMENA - 79 I M S - Observational data of Polar Geophysical Institute USSR Academy of Sciences Editor B.E.Brunelll Apatity, 1983 The volume contains the results of ionospheric observations of Polar Geophysical Institute and continues the series of publications started in 1970 /1-4/, Since 1977 the data are published in two volumes: Auroral Phenomena /2/ with results of geomag­ netic, auroral and balloon observations and Ionospheric Phenomena /3/ with the data of vertical sounding, absorption measurements and radar observations. In Murmansk ionospheric sounding is carried out by means of AIS ionosond with frequency range 1-20 MHz, sweep time of 30 s , height range 1500 km. lonograms are received every 15 min. Information on ionospheric sounding is presented in the form of f-plots with standard /5-6/ designations additionally explained in the Russian text. Absorption measurements at st.Loparskaya were carried out by means of standard riometer frequency of 32 MHz, bandwidth of 90 KHz, time integration 30 s , antenna main lobe 50x60° directed towards the Polar Star, Base line ia derived from quiet days records monthly. Absorption variation is given on the graph, days with complete absence of absorption are excluded. Radioaurora observations at st.Essoila were performed by means of radar on f=88 MHz with bandwidth of 270 kHz, power in pulse 60 kW, the range of 1200 km, the period of antenna rotation 40-90 s . The time of radioaurora occurance is given in Tables. The geographical and corrected geomagnetic coordinates /7,8/ of the stations are given in Table 1. Universal time is used everywhere. The behaviour of the ionosphere significantly depends on the presence of dis­ turbances Their distribution over the year is examined in /4/. In most compact form this distribution is presented in the Calendar, Fig.1. Estimation of activity ia given according to ionospheric, geomagnetic and auroral observations. The growth of activity is denoted by black spots. It is evident that three types of estimation of the activity agree rather well, though the activity level turns up to be slightly different, i.e. disturbances are registered more often from ionospheric indices than from two other forms. Diurnal variations of activity with daytime minimum (the middle of each line), as well as seasonal variations when the activity level is higher in the first half of the year, are seen. The days in the Calendar are ordered according to Bartel’s rotation number 1988-2001. The plot in Pig.2 can also present evaluation of activity since it contains гд daily mean values. The IMP signs (positive from the Sun) are also given. The days with increased activity in the magnetograms are marked. I’ig.1 and 2 show that the tendency for recurrent sequences, though not utterly disappeared, is weakly manifested in the examined year. It is still weaker than in the previous years of deorease of Solar activity. At the beginning of the year the days with highest activity are arranged at the beginning and in the middle of Bartel's rotation, whereas the days at the end of rotation are marked by lower activity. Furtheron, the days at the beginning of rotation become quiet. The duration of activity in the middle of rotation decreases; on the Calendar the region of high activity is wedge-shaped narrowing towards the middle of the year.