THE DRIFT OF SMALL-SCALE IRREGULARITIES IN THE IONOSPHERE (ACCORDING TO MEASUREMENTS AT IRKUTSK)

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• Collection: STARGATE
• Document Number (FOIA) /ESDN (CREST): CIA-RDP96-00787R000500130079-9
• Release Decision: RIFPUB
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• Document Page Count: 12
• Document Creation Date: November 4, 2016
• Document Release Date: October 13, 1998
• Sequence Number: 79
• Publication Date: April 1, 1958
• Content Type: PAPER

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T-RC-21 CIA No. 9678780 PAGES 1 and 2 OF11 PAGES
THE DRIFT OF SMALL-SCALE IRREGULARITIES IN THE IONOSPHERE
(according to measurements at Irkutsk)
by
V. D. Kokourov and E. S. Kazimirovskii
1. INTRODUCTION
An experimental device to investigate horizontal movements in
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[112]
This article gives the results of the observations for the period
from 1 April 1958 through 30 October 1959.
2. APPARATUS
A manually-operated iono?sonde with transmitting, receiving and
recording equipment [41 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 wass of the
*OPrO96d?Pokr'bftrai 200i/6' P2 -'CAA_KD 6f-U07 fR 0580 %d079 9e re-
ceiving antennas were asymetrical dipoles, which are strictly oriented
Fri
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parallel 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 EW
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 up.
,I
L
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, 5- receiver,
6- sweep generator, 7- monitoring oscillograph, 8-receiver antennas,
9- antenna switch, 10- sweep forming unit, 11 and 12- recording unit.
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THE DRIFT OF SMALL-SCALE IRREGULARITIES IN THE IONOSPHERE (CONT'D)
3. OBSERVATIONAL RESULTS
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 ? 0.1 mgc 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 5 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[1'23. 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 E 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
velocity is 60- m c
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6 20 s 0 30 d01001201Vul f601d0 200 V , m/s e c
Pig. 2. Histograms of the magnitude
of the velocity and direc-
tion of drift in the F2 layer
for the period from April 1958
through October 1959.
n-the number of cases
n 2019 ?9 fob, fiaty ti d001 ix V , m/s e c
Fig. 3. Histograms of the magnitude
of the velocity and direc-
tion of drift in the E
layer for the period from
April 1958 through October
1959-
n-the number of cases
Fig. 3 gives corresponding histograms for the E layer. As for
the F2 layer, the drift velocity magnitude in the E 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 relationskiip 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 histo rams. Figure 4 gives the seasonal histo-
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 T-RC-21 CIA No. 9678780 PAGES 5 & 6 OF 11 PAGES
TA1f#1I9FF A - U ? /&y l~ 9 &M,?000 W;9079-9
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 F2 layer, the drift velocity during autumn-and winter reaches
most probable values of the order of 100 m/see which is somewhat higher
than during summer and spring.
Most probable
velocity m/sec
Most probable direction degrees
2 layer E layer:
F2 layer E layer
Spring
N-W (270--3(x))
SE
NE (30-1)0)
(120--1: i
Summer
SE (120- 150)
60-80
80--11ki
NW (270-300)
SE (120-1541
Autumn
60-100
MO --100
NW (270-300,
Nw
SW (210-2.0)
(270-300)
Winter
NW (270--3(0))
SW
SW (210-240)
(210-240)
The drift direction in all seasons was, for the most part, NW (270-
300?) but it was SW (210-2400) 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
stational3l. 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 but the westerl direction (with
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F '
rO Z0 aO f60 100 b.m/s e c
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 ni/E ni are plotted on the y-
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PAGES 7 & 6 OF 11 Pages
THE DRIFT OF SMALL-SCALE IRREGULARITIES IN THE IONOSPHERE (CONT'D
N
I:1 r U11.11 Spring
/sec
f20 fie xb' IV,
. m/s e c
Fig. 5. Histograms of the magnitude of. the velocity and direction
of drift in the E layer for different times of the year.
The relative number of cases ni/ E ni are plotted on the
y-axes and along the radii.
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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
40-100 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 SW 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
E layer at Irkutsk as compared with the data examinedC31 of other
stations, which makes it possible to distinguish the most probable dire-
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 with a 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).
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THE DRIFT OF SMALL-SCALE IRREGULARITIES IN THE IONOSPHERE (CONT'D)
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TABLE
l Station
tio
Ob
V. m/sec
Direction
na
serva
Irkutsk
60-100
NE and SE
Kharkov
40-60
NE,SW (during the day) and
SW (night)
Tomsk
60-80
NE and SW
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T-RC-21 CIA No 9678780
THE DRIFT OF SMALL-SCALE IRREGULARITIES IN THE IONOSPHERE (CONT'D)
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LITERATURE
1. 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.
2. Grishkevich, L. Vol Iu. V. Kushnerevskii and N. A. Mitiakov.
"Izmereniia dreifa v ionosfere (dopolneniia i rekomendatsii)"
(Measurements of drift in the ionosphere (Supplements and
recommendations) Nauchn i Institut Zemno o Magnetizma i
Rasprostraneniia Radiovoln Akadernii Nauk SSSR, (manuscript)
1957.
3. Dreify i neodnorodnosti v ionosfere (Drifts and irregularities in
the ionosphere ,.Izdatel- stvo Akademii Nauk SSSR, Seriia
MGG, No. 1, 1959.
4. Kokourov, V. D. "Apparatura dlia izmereniia vetrov v ionosfere"
(Apparatus for the measurement of winds in the ionosphere),
Tomsk Doklad na Vsessoiuznom mezhvuzovskom soveshanii o
radiofizicheskim metodam issledovaniia ionosfery, 1956.
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