Ионосферные явления-77: материалы наблюдений Поляр. геофиз. ин-та по проекту Междунар. исслед. магнитосферы за 1977г. (оперативно-информационный материал). Апатиты, 1978.

4 IONOSPHERIC PHENOMENA - 77 The IMS - Observational Data of Polar Geophysical Institute Academy of Sciences of the USSR Editor B.E.Brunelli Apatity -• 1978 The volume contains the results of ionospheric observations carried out at stations of Polar Geophysical Institutes ionospheric sounding, ionospheric absorption measurements and the radar observations. The volume continues the series of publication started in 1970 /1-6/, but since this year the data will published in two volumes: "Auroral phenomena" /7/ with the results of geomagnetic, optical and baloon observations and the present volume with the results of ionospheric observations. Ionospheric sounding at at.Murmansk is carried out by means of ionosonde AIS with frequency range 1-20MHz, sweep time 30s, height range 1500km; ionograms are received every 15 min. The information on ionospheric sounding is given in form of f-plots with standard /9/ designations which are additionally explained in Russian text. Por the absorption measurements at st.Loparakaya was used a standard riometer of frequency 32 UHz, bandwidth 9 kHz, time of integration 30s, antenna with main lobe 50x60° directed towards the Polar Star. The base lines were derived on quiet days every month. On the graph the absorption variation is given} the days when the increasings of absorption were not registered were excluded. The radioaurora observations on st.Molodezhnaya (Antarctica) were carried out by means of radar on f>»88MHz, bandwidth 270kHz power in pulse 60 kW, range 1200km, the period of antenna rotation 40-90 sec. The information about the presence of radioaurora is given on tables. Universal time is used everywhere. The geographycal and corrected geomagnetic coordinates /8/ of the stations are given on page 3 . Median values of the critical frequencies during quiet days for different couples of months are given on Pig.2. Days were considered as quiet when there was no magnetic distur­ bances, the diurnal variation of fQF2 wae smooth, the observation of P-region was not inter­ rupted on more than 2-3 hours by absorption or by dense sporadic E-layer. The numbers of euch days in January-Pebruary were 8, in November-December - 9, in March-April - 10, in September-October - 10 and during the rest summer months - 13» During summer months the duirnal variation of frequencies is small, because the ionosphere is limited continuously. At equinoctial seasons in daytime fQJ'2 is higher than in summer, during nighttime - lower, an assymetry is s e e m the increasing of electron denBity occures more rapidly between sunrise and noon, the decreasing between noon and next morning is slowest. In winter months for the variation of fQP2 two maxima are typical near noon and midnight and minima in the beginning and near the end of night. The difference in daily level of f0P2 in the beginning and the end of the year may be connected with the increasing of sunspot numbers. The analysis of activity distribution during the year was carried out in /7/s in simplest form the result is presented in form of calendar, which is reproduced on Pig.3* The calendar gives the activity level on every hour according to the data of ionospheric, geomagnetic and optical observations. Pirst of all it is seen that the three forms of activity are changed simultaneously, with minimum in daytime and maximum at nights. The active days have the tendencies to form a reccurrent sequences. It is noted /1-6,10,11/ that the increasings of activity are connected with the changes of the interplanetary magnetic field (IMP) sector sign end that the high activity during the first half of the year is connected with the negative IMP. During the moat of the Sun^s rotations in 1977 the IMP sign changes many times but as a simplest model may be accepted a 4-eector structure. At the beginning of Bartels rotation IMP sign is changed several times, but mostly the field is negative. The firet part of rotation therefore is considered as belonged to the negative IMP-sector, marked ав "A*. Positive sectors are marked as Вarid D{ the most active (in the f i rat half of the year) sector is the negative С-sector. By the Lattin letters on