Sun and Geosphere, 2015;

10/2: 133 -140

ISSN 1819-0839

Magnetic and Ionospheric Observations in the Far Eastern Region of
Russia During the Magnetic Storm of 5 April 2010
Baishev D.G.1, Moiseyev A.V.1, Boroyev R.N.1, Kobyakova S.E.1, Stepanov A.E.1,
Mandrikova O.V.2,3,4, Solovev I.S.2,3,4, Khomutov S.Yu.2, Polozov Yu.A.2,
Yoshikawa A.5, Yumoto K.5
1

Yu.G.Shafer Institute of Cosmophysical Research and Aeronomy SB RAS,
Yakutsk, Russia
2
Institute of Cosmophysical Research and Radiowave Propagation FEB RAS,
Paratunka, Russia
3
Kamchatka State Technical University, Petropavlovsk-Kamchatsky, Russia
4Saint Petersburg Electrotechnical University "LETI", Saint Petersburg, Russia
5International Center for Space Weather Science and Education, Kyushu University,
Fukuoka, JapanE mail (baishev@ikfia.sbras.ru).
Accepted: 30 September 2015
Abstract. Magnetic and ionospheric disturbances in the far eastern region of Russia during the magnetic storm of 5 April
2010 are studied using data of geophysical stations operated by IKFIA SB RAS and IKIR FEB RAS. By performing wavelet
analysis of experimental data, the wavelet powers of geomagnetic perturbations at different stations are estimated, in an
attempt to investigate the dynamical development of a geomagnetic storm. It is shown that, though weak geomagnetic
disturbances were present prior to the main phase of magnetic storm, the variations of the magnetic field during a storm
development were found to be rather strong. The highest intensity of geomagnetic disturbances during the interplanetaryshock at the Earth's magnetosphere was observed at KTN (L~9) while at ZYK (L~4) strongest geomagnetic perturbations
occurred during the magnetospheric substorm with the onset at 09:03 UT. Large geomagnetic fluctuations were recorded
at TIX and CHD (L~5-6), when the High-Intensity Long-Duration Continuous AE Activity (HILDCAA) was observed on 6 April
2010. Ionospheric conditions at YAK (L~3.4) and PET (L~2.2) were characterized by a pre-storm enhancement in theelectron density in the F2 layer on 4 April 2010 and prolonged negative phase of the ionospheric storm during the main
and recovery phases of magnetic storm on 6-8 April 2010. These experimental results underscore the importance of multiinstrumental observations and provide clues to the complex interactive processes.
© 2015 BBSCS RN SWS. All rights reserved
Keywords: magnetic storm, magnetic and ionospheric disturbances, magnetometer, digisonde, wavelet transformation

Introduction
The response of the ionospheric F layer to magnetic
storms, commonly called ionospheric storms, is known
to be very complex (e.g., Buonsanto, 1999; Mendillo,
2006 and references therein). It consists of positive andnegative phases, the understanding of which is very
challenging in space and in time. The morphologicalfeatures of ionospheric storms and the main processes
controlling their behavior have been described in aseries of review articles (Prolls, 1995; Rees, 1995;
Buonsanto, 1999; Danilov, 2001; Danilov andLaštovička, 2001; Mendillo, 2006). Despite extensive
efforts in observations, theory, and numericalmodeling,
comprehensive
understanding
andaccurate descriptions of ionospheric response tomagnetic storms is far from complete.
The magnetic storm on 5 April 2010 with its
beginning at 08:26 UT was caused by a coronal massejection which was unleashed from the Sun on 3 April
2010, and arrived at the Earth two days later (Möstl etal, 2010). Despite being a relatively weak storm (theminimum Dst was about -50 nT on 5 April) it
nevertheless had some devastating space weather

impacts, including the malfunction of the Galaxy 15
communication satellite (Allen, 2010).
Mandricova et al. (2014) performed a detailed
analysis of the geomagnetic disturbances during
magnetic storm and strong magnetospheric substorm
on 5 April 2010 using data from magnetic stations of
the far eastern region of Russia using in-housedeveloped algorithms. By selected components ofperturbed variations of the magnetic field they defined
the time of occurrence and the periods of mostintense geomagnetic disturbances. Based on the
wavelet technique, spatial-temporal pattern ofmagnetic disturbance development in the region ofinterest was studied by them. Mandrikova et al. (2014b)
analyzed only the cosmic ray data along with thegeomagnetic data in their study. In the present study
using ionospheric data from Paratunka and Yakutsk
along with magnetic data from the far eastern regionof Russia, before and during the magnetic storm of 5
April 2010, the intensity of ionospheric disturbancesalong with the abnormal periods were estimated using
wavelet transforms.
Special attention has been paid to a developmentof sudden storm commencement and global substorm

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Baishev D.G. et.al. Magnetic and Ionospheric Observations in the Far Eastern Region of Russia During the ….

in the interval of 07:00-10:00 UT on 5 April 2010 and prestorm enhancement of critical frequency foF2 at
ionospheric stations Yakutsk and Paratunka on 4 April
2010.

Materials and methods
We used the interplanetary magnetic field (IMF)
and solar wind from the ACE Science Center,
http://www.srl.caltech.edu/ACE/ASC, and magnetic
data from observatories of institutes IKIR FEB RAS andIKFIA SB RAS (see Table 1 and Figure 1).
Three-component
fluxgate
magnetometers
MAGDAS (Yumoto et al., 2006; Baishev et al., 2013) witha sensitivity up to 0.01 nT and sampling of 10 Hz were
installed under Agreements between ICSWSE, Kyushu
University, Japan, and our institutes, including theMAGDAS COLD model (PET, MGD, CPS) and MAGDAS9 model (KTN, TIX, ZGN, YAK, CHD, ZYK). Both onesecond and one-minute values of horizontal

component H of the geomagnetic field were used forwavelet analysis.
Ionospheric data at observatory PET were from an
upgraded old Russain Ionosonde with a digital receiverand computer operation. The peak power of theradiated pulse had been ~2 kW, the frequency range
is about 1-15 MHz.
The Digisonde Portable Sounder DPS (Reinisch et al.,1997) is the system with a low power transmitter (300 W)
employing intrapulse phase coding, digital pulse
compression and Doppler integration and the fourcrossedmagnetic
dipolereceiving
antennas
produced by the University of Massachusetts Lowell’sCenterfor
AtmosphericResearch(UMLCAR,http://ulcar.uml.edu/).
On the basis of the wavelet packet decomposition,
geomagnetic field variation can be represented as(Mandrikova et al., 2013, 2014b):

f 0 (t ) = ∑ c −m ,n ϕ − m ,n (t ) + ∑ ∑ d j ,n Ψ j ,n (t ) + ∑ ∑ d j ,n Ψ j ,n (t ) = f trend (t ) + f dist (t ) + e(t ) , (1)
j∈I n

n

j∉I n

Table 1. List of stations used in analysis. The corrected geomagnetic coordinates (CGM) were calculated for the epoch 2010.0
at an altitude of 110 km using the algorithm based on the DGRF/IGRF geomagnetic field models at
http://omniweb.gsfc.nasa.gov/vitmo/cgm_vitmo.html.
Station

Code

Geodetic
coordinates
latitudelongitude

corr.geomagnetic
coordinates
latitudelongitude

L-parameter

Kotelny

KTN

76.0

137.9

70.7

202.7

9.3

Tixie

TIX

71.6

128.8

66.3

198.2

6.3

Chokurdakh

CHD

70.6

147.9

65.3

213.8

5.8

Zhigansk

ZGN

66.8

123.4

61.7

195.1

4.5

Zyryanka

ZYK

65.8

150.8

60.3

218.3

4.1

Yakutsk

YAK

62.0

129.8

56.6

201.8

3.4

Magadan

MGD

59.6

150.8

53.6

220.2

2.9

Paratunka

PET

52.9

158.3

46.6

227.4

2.2

Khabarovsk

KHB

47.6

134.7

41.5

207.6

1.8

f trend (t ) = ∑ c−6,nϕ −6,n (t )wheredescribes

thenundisturbed level of the horizontal component of the
Earth magnetic field during quiet period, andf dist (t ) = ∑ g j (t ) ,
j∈I

where

g j (t ) = ∑ d j ,n Ψ j ,n (t )ndescribes geomagnetic perturbations. Componente(t ) = ∑∑ d j ,n Ψ j ,n (t ) represents the noise. I is aj∉In

To estimate a power of geomagnetic perturbations
the continuous wavelet transform (Daubechies 1992;
Chui
1992)
determinedasWΨ f b, a := a( ) (Mandrikova et al., 2013, 2014b).

Aj = max d j ,n
n

∞

−∞

f ∈ L ( R), a, b ∈ R, a ≠ 0. has been used
A power of geomagnetic perturbations at the moment

t=b on analyzed scale a is estimated as

eb,a = WΨ f b,a(2)

A power of field perturbations at the time momentt = b isEb = ∑ eb, aa134

t −b

∫ f (t )Ψ a dt,2

set of indices of the disturbed components.
The measure of geomagnetic perturbation
component g j (t ) on the scale j is determined as−1 / 2

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Figure 2 shows the in situ observations by Wind SWE(Ogilvie et al., 1995) and MFI (Lepping et al., 1995). The
first solid line from left is the shock arrival on 5 April 2010,
07:58 UT. The second and third solid lines indicate themagnetic cloud interval, from 5 April, 12:05 UT, to 6
April, 13:20 UT. From profile of IMF Bz it is evident that astrong (minimum = −15 nT) and short interval of
negative IMF Bz in the sheath coincided with the storm
commencement. In the ICME back region, too, it is thenegative IMF Bz which is responsible for prolonging thestorm growth phase. In between these two regions,when IMF Bz ≥ 0 nT, it is the large, negative IMF which
accounts for the continued ring current intensity.
Maximum Kp=8- was registered during sheath event
while minimum Dst =-72 nT was occurred aftermagnetic cloud event on 6 April 2010.
Figure 1: Location of magnetic stations in the far eastern region of
Russia using Google map service.

Selection of anomalies in the ionosphere was basedoncontinuous
wavelettransformation
andthresholding functions:WΨ fb , a , если WΨ f b , a − WΨ fbmed
≥ Ta
,a

PTa (WΨ f b , a ) = ,
med
0, если WΨ f b , a − WΨ f b , a < Ta(4)

where threshold Ta = U * Sta determines a presenceof anomalies on the scale
contained

inthecarriera near the point ξ ,Ψb, a , U is threshold2
1 ΦWΨ fb , a − WΨ fb , a ,∑Φ − 1 k =1(

coefficient, Sta =)WΨ fb , a и WΨ fbmed, a are mean square deviation, meanvalue and median of critical frequency, determined
separately for each hour in a sliding time window oflength Φ .
To estimate the threshold coefficient U we used aposteriori risk (Levin, 1963). Determination of theionosphere status was performed according toionograms
which
also
was
correlated
withgeomagnetic data (using geomagnetic K index). A
power of ionospheric anomalies at a time momentt = b was estimated as

I b = ∑ PTa (WΨ f b,a )(5)aData Analysis
Near-Earth environment
On 5 April 2010 an interplanetary (IP) shock was
detected by the Wind spacecraft ahead of Earth,followed by a fast (average speed 650 km/s)
interplanetary coronal mass ejection (ICME). During
the subsequent moderate magnetic storm (minimum
Dst =-72 nT, maximum Kp=8-), communication with the
Galaxy 15 satellite was lost (Möstl et al., 2010).

Figure 2: Interplanetary magnetic field and solar wind plasma datafrom the Wind spacecraft observations (Möstl et al., 2011).
From top to bottom: magnetic field magnitude andcomponents in GSE coordinates, proton bulk velocity, proton
number density, proton temperature, planetary geomagnetic
indices: Dst (black line, hourly) and Kp (blue bars, every 3
hours). The first vertical solid line from left is the shock
arrival. Second and third solid lines indicate the magnetic
cloud interval.

Geomagnetic field
Figure 3 presents the one-minute variations of thehorizontal component H of the geomagnetic fieldrecorded at stations in the far eastern region of Russia
on 3-7 April 2010. At the beginning of the storm (~08:26
UT on 5 April 2010), a sharp increase of geomagnetic
field disturbances was observed at stations from highto middle latitudes (stations KTN, ZYK, YAK and PET). The
geomagnetic variations during a storm evolution were
dynamic and were followed by a series of intense
fluctuations during the period of 5-7 April 2010 as the
ICME passed across the Earth. The highest
geomagnetic disturbance during the interplanetaryshock at the Earth's magnetosphere was recorded atSpecial Edition “2015 UN/Japan Workshop on Space Weather ”

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Baishev D.G. et.al. Magnetic and Ionospheric Observations in the Far Eastern Region of Russia During the ….

KTN (L~9). When the High-Intensity Long-Duration
Continuous AE Activity (HILDCAA) was observed on
April 6 2010, during the time when large geomagnetic
fluctuations were recorded at TIX and CHD (L~5-6). At
subauroral (ZYK) and middle (YAK, PET) latitudes large
geomagnetic disturbance as spike was occurred
during a magnetospheric substorm with the onset at
09:03 UT on 5 April 2010 (Kleimenova et al., 2013).
The results of the estimation of geomagnetic
perturbation power (see eq. (3)) at Figure 4 show asimilar behavior of geomagnetic disturbances over the
far eastern region of Russia. An increase ofgeomagnetic perturbations was seen at ~08:15 UT on 5
April 2010. During the initial phase of magnetic storm,
the strongest wavelet power of magnetic disturbancewas observed in the interval of 08:43-09:34 UT (stations
KTN, ZYK, YAK and PET). Large increase in geomagnetic
activity was noticed in the night MLT hours during the
global substorm with its onset at 09:03 UT (Kleimenova

et al., 2013), when THEMIS AL was less than -2000 nT(Connors et al., 2011). Note that large magnetic
intensities at TIX and CHD were seen during HILDCAA
event on 6 April 2010
For more detailed picture, we processed onesecond magnetic data (Figure 5) and investigated indetail the time interval of the sudden storm
commencement (SSC) and global substorm from 07:00
UT till 10:00 UT. The wavelet spectra of selected
perturbed component in the magnetic field variations

f dist (t ) (see eq. (1)) presented in Figure 5 shows adetailed space-time pattern before and during theevent at all the stations considered.
All the stations were in the evening sector (seeTable 1), and the positive variations of geomagnetic
field H-component (eastward electrojet) was marked

Figure 3: Variation of the geomagnetic field H-component with 1-min resolution at stations in the far eastern region of Russia on 3-7
April 2010. Large geomagnetic fluctuations at CHD and KTN during HILDCAA event marked by vertical arrows.

136

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Figure 4: Estimation of a power of geomagnetic perturbations on 3-7 April 2010 (in according to eq. (3)). The vertical solid line indicate
a moment of increase of geomagnetic perturbations. Large geomagnetic fluctuations at CHD and KTN during HILDCAA event marked
by vertical arrows.

by red and the negative (westward electrojet) was
marked by blue. At all stations, before the magnetic
storm, an expansion and shift of wavelet power
spectrum towards the high frequency range occurred,
which indicate of the growth of geomagnetic activity.
At high-latitude stations KTN, CHD, TIX positive andnegative perturbations have a general character anda spectrum convergence is observed up to themagnetospheric substorm onset. At ZYK strongest
geomagnetic perturbations occurred during themagnetospheric substorm clearly distinguishing thethree active phase of perturbations. On the other
hand, at mid-latitudes (MGD, PET, KHB) an active
phase from 08:20 to 08:40 UT with a largest
perturbations in the band of 35-60 minutes coinciding
the SSC is highlighted. After the beginning of the storm,
at about 09:30 UT a narrowing and shift of thespectrum to the low-frequency range, whichcharacterizes a decrease of geomagnetic activity,
could be observed.

Ionosphere
It is known that a sharp fluctuations in ionosphericelectron density (ionospheric storm) can be innegative phase (negative ionospheric storm) withlower density, and in positive phase (positive
ionospheric storm) with higher density. Additionalenergy inputs in the polar region and the consequent
temperature increase/thermal expansion are capableof changing the altitude distribution of neutral
constituents of the atmosphere with a net increase in
the concentration of N2 relative to O. The temperaturerises at ionospheric altitudes, resulting in a larger
ionospheric recombination coefficient, and thus
reducing the electron density (Prölss, 1995; Nakamura
et al., 2009). This would lead to a negative ionosphericstorm. On the other hand the mechanism of positive
ionospheric storms cannot be explained by the N2/O
ratio mainly because when the ionospheric plasma
moves to higher altitudes, resulting in reduced N2
density, the recombination coefficient becomes low.

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Baishev D.G. et.al. Magnetic and Ionospheric Observations in the Far Eastern Region of Russia During the ….

The following mechanism is assumed: ionosphericplasma rises to higher altitudes from an altitude ofabout 180 km where typically the production
maximises, resulting in an increased F-layer electron
density (Prölss, 1995; Nakamura et al., 2009). Although
the mechanisms are broadly understood, an accurate
prediction of positive and negative phases ofionospheric storms is difficult due to the absence of
reliable observations in the upper atmosphere.
Therefore, the development of empirical methods forprediction and estimation of ionospheric fluctuations
are considered to have important practical andscientific significance.

starting after first vertical dashed line from left) increaseof the critical frequency foF2 relative to thebackground level (positive phase of ionospheric storm
is shown in Figure 6 by red). The highest intensity of prestorm ionospheric disturbances was observed at YAK(a peak after first vertical dashed line in third panel
from top of Figure 6), the maximum of which coincides
with the maximum at PET, where it occurred in about 6hours before the beginning of the magnetic storm.
Small-scale abnormal changes in the variations ofionospheric parameters during quiet and weakgeomagnetic field conditions were also observed
during the period from 1 April to 4 April 2010.

Results and Discussion

Figure 5. Estimation of a power of geomagnetic perturbations with
1-sec resolution in the interval of 07:00-10:00 UT on 5 April
2010 in color presentation. To show in detail a behavior ofmagnetic activity at middle latitudes the magnetic data fromstations MGD and KHB were additionally used.

The results of processing of ionospheric data using
author’s method (see eqs. (4), (5)) for stations YAK and
PET from 01 to 20 April 2010 are presented in Figure 6.
Joint analysis of the data of these stations (Figure 6)
shows a general behavior of the ionosphere. Intensityof the disturbances in the ionosphere increases
substantially during periods of intense geomagnetic
activity (see variations of K index). The strongest
disturbances were observed on 6-8 April 2010. During
the magnetic storm, the electron density in the F2 layer
was significantly lower (more than 2.5 standard
deviations from the background level in the intervalmarked by second and third dashed line in Figure 6)
and a prolonged (~3 days) negative phase of theionospheric storm was registered (shown in Figure 6 byblue color).
From Figure 6 a pre-storm enhancement in theelectron density in the F2 layer on 4 April 2010 is seen as
an abnormal (more than 1.5 standard deviations

138

The analyzed magnetic event was observed on the
Earth's surface at 08:26UT of April 5, 2010 and was
identified as a magnetic storm with SSC. The speed of
the solar wind during 07:22 to 08:03 UT had increased
from 750 to 900 km/s. A globally observed intense
substorm emerged 30 minutes later in the Earth's
magnetosphere (Kleimenova et al., 2013). A substorm
growth phase and localized dipolarization at 08:47 UT
were followed by large dipolarizations at 09:03 and
09:08 UT, observed by GOES 11 in the midnight sector,
and also by the three THEMIS spacecraft near X = −11,
Y = −2 RE (Connors et. al., 2011). Strong (THEMIS AL wasless than -2000 nT) substorm interval was associatedwith the loss of communication with the Galaxy-15
satellite (Allen, 2010; Denig et al., 2010; Connors et al.,2011). During this substorm interval, localized andbroad regions of ion energization were observed,
demonstrating that magnetic reconnection andcurrent disruption may have played a role during thisvery extreme event (Keesee et al., 2014).
Our results are in agreement with the above
mentioned ones and most intense geomagnetic
disturbances at stations in the far eastern region of
Russia were observed in the interval of 08:34-09:34 UT
due to SSC and substorm activity. The most intense
geomagnetic disturbances during the event wasobserved at KTN (L~9) in the evening sector, but in thesameinterval,
thestrongest
geomagnetic
perturbations occurred at ZYK (L~4).
The geomagnetic activity associated with sporadic
and continuous magnetic field reconnection undersouthward IMF component can last from days to a
week and has been referred to as high-intensity longduration continuous AE activity (HILDCAA) events(Tsurutani and Gonzalez, 1987). It is believed that somefeature of these continuous (sporadic) plasma
injections/HILDCAAs are the cause of the accelerationof magnetospheric energetic electrons to highenergies.
For the analyzed event, IMF Bz remained negative
during for ~1 day on 6 April 2010, except where it
exhibited a northward peak (Figure 2). Figure 4 shows
intense magnetic fluctuations at TIX and CHD (L~5-6)
on 6 April 2010.

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Figure 6: Variations of F2 layer critical frequency and results of wavelet analysis at YAK and PET, variations of geomagnetic K-index
calculated using magnetic data at PET on 1-20 April 2010. For ionospheric stations YAK and PET are presented the highlighted
anomalies (red - positive anomaly, blue - negative anomaly) and evaluation of wavelet power of ionospheric anomalies. Red
rectangle marks the time interval filled by median values during data gap. The first vertical dashed line from left is moment of apre-storm enhancement in the electron density in the F2 layer. Second and third dashed lines indicate interval of negative phase of
the ionospheric storm.

Shimeis at al. (2012) have studied the ionosphericmagnetic disturbance during a strong magnetic storm
on 5 April 2010 using GPS stations and MAGDAS stationin Egypt. It is shown that at the beginning of the storm,
an effect of the prompt penetration of themagnetosphere electric field was observed whichstrongly increased the TEC. During the recovery phaseof the storm a signature of the ionospheric disturbance
dynamo due to wind produced by Joule heating in theauroral zone was registered.
Fathy et al. (2014) continued an analysis of themagnetic storm on 5 April 2010 to separate themagnetic disturbance associated to the ionosphericdisturbance dynamo (Ddyn) from the magnetic
disturbance associated to the prompt penetration ofmagnetosphericelectric
field
(DP2)
using
INTERMAGNET magnetometers along three longitudinal

sectors: African-European, Asian, and American. It isfound that, in the different longitude sectors, theresponses of ionospheric disturbance dynamo had
been different. On the first day, 5 April 2010, all
INTERMAGNET
stations
exhibitedsimilarandsimultaneous signature of the prompt penetration of
the magnetospheric convection electric field at theEuropean-African sector. On 6-8 April 2010 the
disturbance is different from one station to anotherstation. This fact indicated that the disturbance is notdue to prompt penetration of the convection electricfield. The Ddyn disturbance reduces the amplitude ofthe daytime H component at low latitudes during thefour consecutive days.
Our ionospheric data highlights the effect of theprompt penetration of the convection electric field
which drastically decreased the foF2 values at YAK

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Baishev D.G. et.al. Magnetic and Ionospheric Observations in the Far Eastern Region of Russia During the ….

and PET. On 6-7 April 2010 at YAK and PET, prolonged
negative phase of the ionospheric storm (blue color in
Figure 6) was observed. Such behavior of theionosphere
shown
by
the
ground-based
measurements, as well as total electron concentration(TEC) data, before and during the periods of strong
and moderate magnetic storms is noted in (Buresova
and Laštovička, 2007; Mansilla, 2007; Lui et al., 2008a,b;Nogueira et al., 2011; Saranya et al., 2011; Adekoya
and Chukwuma, 2012; Danilov, 2013; Mandrikova etal., 2015). A significant relationship between theintensity of ionospheric anomalies and frequency of
their occurrence, on the one hand, and of solar andgeomagnetic activity on the other is shown fordifferent regions in (Lui at al., 2008a,b; Nogueira et al.,2011; Saranya et al., 2011; Danilov, 2013; Mandrikova
et al., 2014a, 2015).
Special attention in the recent researches (Kane,
2005; Buresova and Laštovička, 2007; Lui et al., 2008a,b; Danilov, 2013) have been paid pre-storm
enhancements of critical frequency foF2 and TEC.
Results (Kane, 2005; Lui at al., 2008a, b; Nogueira et al.,2011; Danilov, 2013; Mandrikova et al., 2015) are shownthat pre-storm enhancements in the ionosphere canoccur in the background of quiet and weakly
disturbed geomagnetic field and their duration canrange from a few hours to half a day. These results
show that the effect is evident, but some questions
about the nature and mechanisms remain still open.
Analysis of the event on April 5, 2010 (Figure 6) confirm
these effects and illustrates a common picture of the
behavior of ionosphere over Russian Far East. The key
question is, whether pre-storm ionospheric disturbances
are linked with geomagnetic activity. The authors areof the opinion presented in the review by Danilov(2013), and believe that such ionospheric effects areassociated with a certain channel of energy
penetration from the interplanetary space andmagnetosphere. In this case, pre-storm ionosphericdisturbances may signal the forthcoming geomagnetic
storm that has important applications (Adekoya and
Chukwuma, 2012; Danilov, 2013).
The present results also demonstrate theeffectiveness of the proposed computing solutions,which allowed us to highlight effects and perform adetailed analysis of the dynamics of the ionosphere
during disturbed period in the presence of a large
number of missing data (gaps associated with strong
disturbances in the ionosphere and the limited
capacity of the ionosondes).

Acknowledgments
This work was supported in part by JSPS Core-toCore Program (B. Asia-Africa Science Platforms),
Formation of Preliminary Center for Capacity Building
for Space Weather Research and International
Exchange Program of National Institute of Information
and Communication Technology (NICT), the grant of
the Russian Science Foundation № 14-11-00194 (MOV)and the Russian Foundation for Basic Research (grants
15-45-05090 (MAV), 15-45-05108 (BDG)).

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