i
Approved For Refuse 2001 /03/2aLl£IA-RDP96-00MR0005001 30079-9
T-RC-21
CIA No.
9678780
PAGES
1 and 2 0F11 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
4.
4-4
[1 , 2 ]
stations
•
This article gives
the results
of the observations
for
the period
from
April 1958 through 50 October 1959*
2.
APPARATUS
A manually-operated ionosonde with transmitting,
receiving and
recording equipment C4]
is used to study the drift
of the small-scale
irregularities in the ionosphere.
The
frequency range is 1 . 5-16.0
rage,
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 was of the
caiving antennas were
asymetrical dipoles, which are strictly or en e
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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.
1-
6 -
9-
Fig.
1.
A block-diagram of the
set
up
for investigating the drift
of
the
small scale irregularities in the ionosphere.
the transmitter,
2-
sweep generator,
7—
antenna switch,
10-
modulator,
3- timer,
4- height marks,
5- receiver,
monitoring oscillograph,
8-receiver antennas,
sweep
forming unit,
11 and 12- recording unit.
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njA No.
9678780
P*OES
3 & k OF 11 PAGES
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THE DRIFT OF SMALL-SCALE IRREGULARITIES IK 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.
Ihe observations
were made on frequencies of 2.1
1 0.1 mgc hourly on Regular World Days,
Special World Intervals
and Regular World Intervals and on the additional
3-4 dals 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 Cl ’ 2]
.
Processing
by this method yields approximately 3Q-ko% 0 f 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
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t’ig.
2.
Histograms of the magnitude
Fig.
3*
Histograms
of
the magnitude
of
the velocity and direct
of
the
velocity and direc-
tion of drift
in the F2 layer
tion
of drift in the
E
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
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 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 histograms.
Figure k gives
the seasonal histo-
grams
T-RC-21
CIA No. 967878O
PAGES 5 & 6 OF II PAGES
iMMamMKBiMtt
W ^°79 '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
th 6 F2 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.
Season
Most probable
velocity m/sec Most probable direction degrees
F2 layer E layer
F2’ layer
S layer
Spring
60—80
60—80
NW
(270—300)
SE
NE
(30—60 )
(120— I.mo
Summer
SE
( 120-
150 )
'
60—80
80— 10.)
NW
(270—3001
SE
(120—150
Autumn
60—100
80-100
NW
(270-
.300
NW
SW
(210—240 )
(270—300)
Winter
60-100
100—UO
NW
(270—300 )
SW
I
SW
(210—240)
( 210-240 )
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
[3]
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,
but
the westerly direction (with
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slignt deviations
to the north
ana south)
is general.
A westerly
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- 122
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w
to m m
zoo
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o
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to
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Winter
\
—
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&
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FiK
4.
Histograms of
the magnitude of the velocity and direction
Fig
.
in the K layer for different tice.ofth. year.
The relative number of cases
n±/S n±
are plotted on the y
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-
T-RC-21
CIA No. 967878O
PAGES 7 & 8 OF 11 Pages
THE DRIFT OF SMALL-SCALE IRREGULARITIES IN THE_IONOSPHERE
(CONT’D)
Spring
vt .m/sec
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 n^/ 2 n^ are plotted on the
y-axes and along the radii.
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- 124 -
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 examined
of other
stations,
which makes
it possible
to distinguish the most probable dxre-
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 ra/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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- 126
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TABLE
Observational Station
V. m/sec
Direction
Irkutsk
Kharkov
Tomsk
60-100
40-60
60-80
NE and SE
NE f SW (during the
day)
and
SW (night)
NE and SW
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CIA No 9678780
PAGE 11 OF 11 PAGES
THE DRIFT OF SMALL-SCALE IRREGULARITIES IN THE IONOSPHERE
(CONT’D)
- 127
-
LITERATURE
1«
Beynon,
W.
J.
G.
and
G.
W.
Brown,
(Ed.)
The measurement of iono-
spheric drift.
Manual,
Vol.
Ill,
No.
5,
1956,
London Per-
gamon Press,
1957.
2.
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
Zeranogo Magnetizma
i
Rasprostraneniia Radiovoln Akademii Nauk SSSR.
(manuscript)
19577
*•
3»
Dreify
i neodnorodnosti
v ionosfere
(Drifts
and irregularities in
the ionosphere),
Izdatel*
stvo
Akademii Nauk SSSR,
Seriia
MGG,
No.
1,
1959.
Kokourov,
V.
D.
'*Apparatura dlia izmereniia vetrov v ionosfere"
(Apparatus
for the measurement
of winds in the ionosphere),
Tomsk,
Doklad na Vsessoiuznom mezhvuzovskom soveshanii po
radiofizicheskim metodam issledovaniia ionosfery,
1956.
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