LLL LL —_ ‘Approved For Reletise 2001/03/261 €IA-RDP96-00787R000500130079-9 T-RC-21 CIA No. 9678780 PAGES 1 and 2 OF11 PAGES THE DRIFT OF SMALL-SCALE TRREGULARITIES IN THE IONOSPHERE (according to measurements at Irkutsk) by V. D. Kokourov and E. &. Kazimirovskii 1. INTRODUCTION An experimental device to investigate horizontal movements in y the ionosphere was built in accordance with the IGY program at the : ionospheric laboratory of the Irkutsk Magnetic-Ionospheric Station of the East Siberian branch of the Academy of Sciences USSR. From April 1958, regular observations of the drift of the small scale irregularities in the ionosphere were initiated by the method of spaced reception with a small base. The observations were carried out according to the pro- gram of the IGY and of the additional instructions for the Soviet Union stations (24, This article gives the results of the observations for the period from 1 April 1958 through 30 October 1959. 2. APPARATUS A manually-operated ionosonde with transmitting, receiving and recording equipment “+! is ‘used to study the drift of the small-scale irregularities in the ionosphere. The frequency range is 1.5-16.0 mgc, the power, of the order of 20 kv in an impulse with a 100 micro- sec duration, a frequency repetition of 50 cycles. A sectionalized rhombic vertical antenna with a 700 ohm load resistance was used for the emission. A VS=342 receiver adapted for impulse reception was used to receive reflected signals. The transmission band wae of the ddprovéPPorikereaserze04 dare" tid RO HGE.Jé787RGHG560130079-9 ceiving antennas were asymetrical dipoles, which are strictly oriented
0 en, s Approved For Retwtise 2001/03/26 : CIA-RDP96-00787R000500130079-9 - 118 - paralle}] to each other along the 110° azimuth, located at the vertices of an equilateral triangle with the legs, 120 m lying in a NS and BW direction. The receiving antennas, using a high-frequency RK=-1 coaxial cable installed under the ground, are connected with the antenna switch, which alternately connects them to the same receiver. The amplitude of the signal received from the oscillograph screen with a three-track scan is photographed on 35 mm film with an advance rate of 14.6 cm/min. Figure 1 gives a block-diagram of the set upe Fig. 1. A block-diagram of the set up for investigating the drift of the small scale irregularities in the ionosphere. 1- the transmitter, 2- modulator, 3- timer, 4- height marks, 5S- receiver, 6= sweep generator, 7- monitoring oscillograph, 8-receiver antennas, Q- antenna switch, 10- sweep forming unit, 11 and 12- recording unite Approved For Release 2001/03/26 : CIA-RDP96-00787R000500130079-9
T-RC-21 CTA No. 9678780 "PAGES 3 & h OF 11 PAGES Approved For Reles8e 2001/03/44.9 GIA-RDP96-0078%R000500130079-9 THE DRIFT OF SMALL-SCALE IRREGULARITIES IN THE IONOSPHERE (CONT 'D) 3e OBSERVATIONAL RESULTS renee niin The horizontal movements in the E and F2 regions of the ionosphere were studied. The method of measurements is based on a study and com- parison of the nature of the behavior of the unit Signals reflected from the ionosphere and taken at three scattered points. The observations were made on frequencies of 2.1 2 0,1 mge hourly on Regular World Days, Special World Intervals and Regular World Intervals and on the additional 3-4 days recommended for the Soviet Union Stations. The duration of the session was 2 minutes in the interval from 00 to 08 minutes every hour. The magnitude of the velocity and direction of the drift of the small scale irregularities were determined from the mean time shifts of the usual parts of the recordings of the fadings 1+21, Processing by this method yields approximately 30-40% of all recordings. A series of observational sessions were eliminated from the processing due to strong radio~interference, considerable absorption or because of the presence of large diffusion in the ionosphere, Recordings of fadings were obtained with a high degree of similarity, slight similarity and they were random. For the most part the fadings were of a periodic or quasi-periodic nature with a 0.1-5.0 second period. The angle deter- mining the direction of movement is read clockwise. It should be noted that the method we use, generally speaking, does not give a well-defined determination of the height at which the actual drift Occurs. However, there is basis to assume that in the case of measur~ ing drifts from the echoes from the £ layer during the day and from the F2 layer at night (with the absence of random E at this time) the measurement data can pertain to the corresponding layer. Figure 2 gives histograms of the magnitudes of the velocities and directions of drift of the small scale irregularities in the F2 layer. It is evident from these histograms that the drift velocity lies with- in the limits 20-200 m/sec, whereupon the most probable value of the (oo Appyoved Hor Réigasd 2001103798. CIATROP9s-00787R0G9500+ 80079-9
-~ e Approved For Refease 2001703126 : CIA-RDP96-00787R000500130079-9 Fig. 2. Histograms of the magnitude Fig. 3. Histograms of the magnitude of the velocity and direc- of the velocity and direc- tion of drift in the Fe layer tion of drift in the i for the period from April 1958 layer for the period from through October 1959. April 1958 through October n-the number of cases 1959. n=the number of cases Fig. 3 gives corresponding histograms for the HE layer. As for the F2 layer, the drift velocity magnitude in the BE region lies within the same interval 20-200 m/sec. However, the most probable values of the velocity are 80-100 m/sec. In this case, the drift direction is primarily eastward (30-60 and 120-150°). To establish the seasonal relationship of the drift of the small scale irregularities, histograms were compiled of the magnitudes of the velocity and direction of the movement for each month, which were then entered on the seasonal histogr « Figure ives the seasonal histo- ams kg grams Approved, or Re lease 2 91/03/28 ; CIA-RDOP9B00787R000500330979-9
T-RC-21 CIA No. 9678780 PAGES 5 & 6 OF 11 PAGES TiARPRERNCELFOR REGS 2ROHOSIRE .ClAR RRR AORETR00 5004 30079-9 gives the seasonal variation of the most probable values of the velocity and direction of the drift. It is evident from figure 4 and table 1 that for the Fe layer, the drift velocity during autumn and winter reaches most probable values of the order of 100 m/sec which is somewhat higher than during summer and spring. Most probable velocity m/sec Most probable direction degrees Season | 2 layer E layer] F2 layer Spring 60-—80 NW (270-—300) SE NE (30-60) (120—-120 Summer SE (120-150) * 60—80 BU-— 100 Nw (270—300) SE (120-150 Autumn 60—100 80 —~100 Nw (270-300; NW Sw (210—240) (270—300) Winter 6-100 | 100—140 Nw (276--300) Sw (210—240) (210—240) SW The drift direction in all seasons was, for the most part, NW (270- 300°) but it was SW (210-240°) during spring and autumn. For the E layer, the drift velocity during winter is higher than during summer and reaches a most probable value close to 140 m/sec. During spring and summer the drift direction is eastward, while during autumn and winter it is westward. We were able to compare our data with the results of investigations of drifts of the small scale irregularities made at other Soviet Union stations!?/, Table 2 gives a comparison of the results of the observa- tions for the F2 layer. Table 2 shows the more frequently encountered values of the magnitude and direction of the drift velocity for dif- ferent seasons and for the entire observational period. The comparison shows that the velocity value by seasons is in good agreement for all the examined stations. During the spring there is an increased scat- ter of directions for all the stations e westerly direction (with oi /perovedd For Release, 200103126 -.Clk sO p96:0078/ Rogosseesg5 go8 wester
~ ° Approved For Reléwee 2001/03/26 : CIA-RDP96-00787R000500130079-9 2 122 - m/gec | HULL £0 120 60 20 im/eec Autumn 7 | {k= Ww 36 120 60 20v.m/sec Winter Fig. 4, Histograms of the magnitude of the velocity and direction of drift in the F2 layer for different times of the year. The relative number of cases n /% ny are plotted on the y- Approved Fat fees 200 (04126 C1A-RDP96-00787R000500130079-9
Approved For Relw&se 2001/03/26 : CIA-RDP96-00%87R000500130079-9 - 123 ~ T-RC-21 CIA No. 9678780 PAGES 7 & 8 OF 11 Pages (cont !D) ¢ 0 We 120 10 to y.m/Sec G25 Autumn ans VA 0 4 #0 120 60 way m/sec. ast ¥ Winter qf ib gy 0 40 4 20 60 Ym/sec Fig. 5. Histograms of the magnitude of the velucity and direction of drift in the E layer for different times of the year. The relative number of cases n,/ 2 n, are plotted on the y-axes and along the radii. * Approved For Release 2001/03/26 : CIA-RDP96-00787R000500130079-9
- ze Approved For Release 2001/03/26 : CIA-RDP96-00787R000500130079-9 direction prevails during summer. During autumn, a westerly direction (210-240 and 270-300°) prevails for Irkutsk, then, on the other hand, an easterly drift direction is noted for Moscow and Tomsk along with the westerly direction. During winter, the direction is also westerly for all stations. A comparison of the data for the E layer for Irkutsk, Kharkov and Tomsk with the date given in table 3 shows that the magnitude of the most probable velocity for all three stations lies within the interval 4Q«100 m/sec, while the general direction is NW. At the same time, the drift direction, compared with number of appearances with the NE direction is $W in Kharkov and Tomsk. A SW direction is seldom observed in Irkutsk. Here the additional direction is SE. In our opinion, such a divergence is explained by the number of observations in the (31 of other stations, which makes it possible to distinguish the most probable dire- B layer at Irkutsk as compared with the data examined ctions of the movement in the E layer with great accuracy. 4. CONCLUSIONS The observations of the drifts of the small scale irregularities in the ionosphere over Irkutsk have indicated that regular drift with a velocity of 60-80 m/sec in a principal westerly direction takes place in the F2 layer. The drift velocity has a sharply defined seasonal variation. The observations verified the presence of the drift of the small scale irregularities in the E layer witha velocity of 80-100 m/sec in a principal EW direction. The drift velocity for the E layer also has a sharply defined seasonal variation. The comparison of the obtained data with the data of other inves~ tigations verifies the presence of a common circulation system in the ionosphere. At the same time, the drift of the small scale irregularities is also characterized by local peculiarities (additional directions, daily variation, etc). Approved For Release 2001/03/26 : CIA-RDP96-00787R000500130079-9
hegs0,2001 103/26 : CHE-RDP96 -00HRZRON05001 acess tere THE DRIFT OF SMALL-SCALE IRREGULARITIES IN THE IONOSPHERE (CONT'D) ad 7.ARproved Rex Re a ne ints AN AS S9023ep doos/w ‘A gS fey-2¢ qdeg | 001-08 00t—OL 09—0F I yswoy, S (o¢i—oz}) 2S AS (oez—o2z) AS (orz—orz AS | (opz—orz: AS | | | eg go unpeuer peqeuxysy (ose) AN 08 (orz—08z) aS 008 F—09 O22, ° as a0 (ooe—017. aK 001-09 123TH (082) MN (ove—01z) 5 = (oot) aS v8 —09 (ooe—ouz We 00+—09 CUTER (082) MN “8 -09 (008-012 MN os—09 seul (ooe—orz AN # (082) AN (ost}—0z1) HS Co) (00H)} as 99°—-0F (o9—0e) SIN | 08—09 suTgi ~ | seeagep 4 oes/m ‘A io | | seas QS 2eq~9g UeLr 66°290-96 TTady ue Ki mooSsOW 43S4nxII 5 Q. roy <x e wldva Seerfep 4 29S/W °A} seeaSep 4 29S/u ‘A (o0e—022" CIA-RDP96-00787R000500130079-9 og—og POTIed eating bee
Nook *“ Approved For Redéase 2001/03/26 : CIA-RDP96-08787R000500130079-9 - 126 - TABLE Observational Station Vy m/sec Direction Irkutsk 60-100 NE and SE 40-60 NE,SW (during the day) and Mnarkov SW (night) Tomek 60-80 NE and SW Approved For Release 2001/03/26 : CIA-RDP96-00787R000500130079-9
ad * «+ Approved For Relea€é 2001/03/26 : CIA-RDP96-00788R000500130079-9 T-RC-21 CIA No 9678780 PAGE 11 OF 11 PAGES THE DRIFT OF SMALL-SCALE IRREGULARITIES IN THE IONOSPHERE (CONT'D) - 127 - LITERATURE 1. 3e Beynon, W. J. G and G W. Brown, (Ed.) The measurement of iono- Spheric drift, Manual, Vol. III, No. 5, 1956, London Per- gamon Press, 1957. Grishkevich, L. V., Iu. V. Kushnerevskii and N. A. Mitiakov. "Izmereniia dreifa v ionosfere (dopolneniia i rekomendatsii)" (Measurements of drift in the ionosphere (Supplements and recommendations) Nauchnyi Institut Zemnogo Magnetizma i Rasprostraneniia Radiovoln Akademii Nauk SSSR, (manuscript) 1957. Dreify i neodnorodnosti v ionosfere (Drifts and irregularities in the ionosphere), Izdatel- stvo Akademii Nauk SSSR, Seriia Kokourov, V. D. "Apparatura dlia izmereniia vetrov v ionosfere! (Apparatus for the measurement of winds in the ionosphere), Tomsk, Doklad na Vsessoiuznom mezhvuzovskom soveshanii ° radiofizicheskim metodam issledovaniia ionosfery, 1956. Approved For Release 2001/03/26 : CIA-RDP96-00787R000500130079-9