Data Analysis Center for
Geomagnetism and Space Magnetism,
Graduate School of Science,
Kyoto University

World Data Center for Geomagnetism, Kyoto

Outline of Data Analysis Center for
Geomagnetism and Space Magnetism
The Data Analysis Center for Geomagnetism and Space Magnetism

Educationofundergraduate andgraduate school students
using geomagnetic data

has dual aspects: it is a facility of the Graduate School of Science, Kyoto
Universit y and, at the same time, it is par t of the internationalorganization, World Data Centers. As a university institution, we are in
charge of student education as well as scientiﬁc research on
Geomagnetism and Space Magnetism. On the other hand, it is also ourtask to collect geomagnetic data f rom all over the globe and distribute
those data to researchers and data users, as a World Data Center for
Geomagnetism.
It is a unique feature of the Data Analysis Center for Geomagnetism
and Space Magnetism that three elements; “education” , “research” anddata
services for

Geomagnetic

researchers and the
public“data service” , are contained in one institution. This is the very reason

Researchon
geomagnetism andspace magnetism
utilizing geomagnetic
data

why the advanced and cutting-edge research, education and data service
are possible here in the Data Analysis Center for Geomagnetism andSpace Magnetism, Graduate School of Science, Kyoto University.

Synergy of the three elements above enables theadvanced research, education and data services.

International Council
for Science (ICSU)World Data Centre(WDC) Panel

WDC forGeomagnetism, Kyoto

Kyoto University

Graduate School of
Science

Data Analysis Center for
Geomagnetism andSpace Magnetism

History
Forerunner: World Data Archive for
Geomagnetism
In 1957, in order to put the International Geophysical Year (IGY ) into eﬀect, an IGY Special Committee of
ICSU proposed to found several WDCs all over the world so as to promote exchange of data. The Faculty of
Science, Kyoto University was assigned to establish WDC-C2 for Geomagnetism since it was well-known for its
achievements in geomagnetic research. It led to the foundation of the World Data Archive for Geomagnetism in
Kyoto University Library in December, 1957.
The archive serviced geomagnetic data for 19 years owing to voluntary work by faculty members of Science,
Engineering and Liberal Arts in addition to the eﬀort of a newly designated administrative staﬀ, both of which were
supported by provisional research budgets.

Consideration by Science Councilof Japan (SCJ)
In May, 1976, the STP Subcommittee of SCJ’ s Special Committee on International Cooperation considered what
WDCs in Japan ought to be. As a result, the committee adopted the resolution that the existing archive should bereformed to be a new research institution, since the role of the archive in promotion of research on Geomagnetism
and Space Magnetism was predicted to become more and more important.

1

Establishment of Data Analysis Center
for Geomagnetism and Space Magnetismand thereafter
Data Analysis Center for Geomagnetism and Space Magnetism was established as a new institution in

April 18th, 1977

the Faculty of Science, Kyoto University. An associate professor was assigned.

1979

Moved to the 3rd ﬂoor of a new building (4th Bldg. of Faculty of Science)1980

An assistant professor position was assigned.

1981

The 1st issue of the AE-indices Data Book was published and distributed.

1982

A technical staff position was newly assigned.

1983

A geomagnetic database “GEOMAG” was instigated within the Computing Center, Kyoto University
Group Achievement Award was given by NASA for successful analysis of MAGSAT data

1985

Dst index was computed and has been distributed since October, 1985.

1988

A Solar-Terrestrial Physics database “STP” was constructed within the Computing Center, Kyoto University

1990

Geomagnetic observations were initiated at Shigaraki MU radar observatory.
1st Bimonthly “WDC News” issued.
Dst index with high temporal resolution (ASY/ASM indices) ﬁrst computed.
Quasi-realtime data acquisition initiated by Intermagnet Project.

1993

Geomagnetic observations at Mineyama DPRI Observatory in Tango Peninsula were initiated.
Data transmission by way of Meteorological Satellite “Himawari” commenced from Tixie (TIK), Russia

1995

The oﬃcial web page of this centre was opened.
Quick Look of AE and Dst indices began.

1996

Quick Look geomagnetic data exhibited from web page.
Realtime detection of Pi2 geomagnetic pulsations began.

1998

Reorganized as an institution of Graduate School of Science, Kyoto University.

1999

A full professorship was newly assigned.

2000

Analog data began to be made on-line.
Geomagnetic observation started at Urumqi (WMQ) in China with one second time resolution.

2004

Geomagnetic observation started at Phimai in Thailand.

2005

Realtime data transfer commenced from Aso, Japan and Iznik, Turkey.

2007

Magnetometers were installed at Tbilisi (TFS), Georgia.
Index for Pi2 geomagnetic pulsations began dissemination via the web.
Magnetometers were installed at Alibag (ABG), India and realtime data transfer started.

2008

World Data Center for
Geomagnetism, Kyoto
Mineyama
CCS
ABK

LRV
FUR

TFS

DIK

PBK BRW

TIK

NAQ

CMO
YKC

PBQ

WMQ

Iznik

FRD

KAK
Phimai
ABG

FCC

Aso

Shigaraki

0

TUC
HON
SJG

ANC
HUA

HER

2

200km

Importance of Research on Geomagnetism
and Space Magnetism
What’s the geomagnetic ﬁeld?
The Earth's core behaves like a very large magnet. The geomagnetic
ﬁeld associated with the core is like a magnet oriented South-North.
Like poles of two magnets repel. Therefore a north seeking compass
will direct itself toward the south oriented magnet inside the Earth.
Hence the term North Pole to a person holding a compass. The

S

geomagnetic ﬁeld is directed into (out of ) the Earth in the northernN(southern) hemisphere in the vertical plane. At the equator there isno vertical part of the ﬁeld. Only a horizontally directed ﬁeld exists.
Whilst at the poles only the vertical part exists. Everywhere else theﬁeld is made up of vertical and horizontal parts. (refer also to acolumn on P.8).

The magnetic ﬁeld
around a bar magnet.

In the vicinit y of Japan, the hor iz ontal component of thegeomagnetic ﬁeld is as large as approximately 30,000 nT, while thestrength of the vertical component is between 35,000 and 40,000 nT.
Magnetic Intensity of Celestial Bodies

Name
Magnetic Moment(Am2)Sun(variable)
Mercury
4.5x1019
Venus< 5.0x1019
Earth
7.9x1022
Moon< 1.1x1016
Mars< 2.0x1019
Jupiter
1.6x1027
Saturn4.3x1025
Uranus
3.9x1024
Neptune2.0x1024
Neutron Star
Magnetar

Surface Intensity(nT)Earth(very weak)(very weak)~ 3x104 at the equator(very weak)(very weak)~ 4x105 at the equator~ 2x104 at the equator~ 3x104 at the equator~ 2x104 at the equator~ 1016~ 1019(?)

The internal part of
the geomagnetic ﬁeld
surrounding the Earth.

nT, nanotesla, is a unit for strength of magnetic ﬁeld (or magnetic
induction). Medical magnets on the market are as strong as 108nT!

*

H OR X- COMPONENT

2000: LOCAL MIDNIGHT
NT
100

1 day

VAL
(56.2)The geomagnetic ﬁeld is perpetually varying. It even changes its
polarity once in 105 - 106 years. There were many occasions in the past

STJ
(57.9)

that the N-pole of a magnetic compass pointed toward not the north but

FRD

the south. We call the temporal geomagnetic variation with a timescale

TUC

of 10 - 1,000 years the as ‘secular variation’ in which strength as well as(49.1)

same variation(40.4)

direction of the geomagnetic ﬁeld vary. ‘Geomagnetic storms’ have a

HON

duration of several days, during which the geomagnetic ﬁeld is severely

KAK(21.5)

disturbed from the normal. There is another phenomenon called a(26.6)‘substorm’, in which the geomagnetic ﬁeld in the polar region is

WMQ

perturbed by strong electric currents ﬂowing in the upper atmosphereABG(33.4)

Bright auroras show intense(9.6)

variations at the time of substorms. These both occur because of unusual

HER

activity on the Sun.

ANC

with a timescale of tens of minutes.

The geomagnetic ﬁeld has also periodic variations at some speciﬁc(-33.7)(-0.8)

periods of 27 days or 11 years. These periodic variations are considered

Kp 2

2-

due to respective periods of solar rotation or activities. In addition, the04geomagnetic ﬁeld shows daily variations because of the Earth’ s(day/night) rotation.

1-

2

8

1+

12

1+

16

1+

20

0+

0

0

0

4

1-

1+

8

1-

1-

12

16

DEC 19DEC 20(DAY 354)(DAY 355)

20

A two-day plot of temporal geomagnetic variations.
All observatories show daytime variations.

3

1+

1-

0

9.4

9.2

dr i
ward
West

f t in

Dipole Moment (1022 Am2)

D=0 at 1700

ears
300 y

9.0

8.8

8.6

8.4

8.2

D=0 at 2000

8.0

7.8
7.7
1600

1700

1800

1900

2000 (year)
2010

Secular variation of declination (angle between geographic andVariation of Geomagnetic Field Intensity

geomagnetic north)

The strength of the geomagnetic ﬁeld has been decreasing for) are superimposedover several hundreds of years. If the decrease continues, weon a map of declination published in 1702 by Sir Edmund Halley

shall have no geomagnetic ﬁeld within 1,000’s of years. It,(blue lines

however, is very diﬃcult to predict whether it is going to be

Contours of declination in 2000 (red lines). It is evident from the ﬁgure that the line of null

declination (a line along which magnetic compasses point toward

true in the future, or the decrease is momentary.

the true north: the thick red line) has shifted toward the west as
large as 70 degrees over 300 years.

How is the ﬁeld generated ?
It is sure that the dynamo mechanism taking place in the
Earth’ s outer core is playing an essential role in making the Eartha very large magnet, although the precise mechanism of the eﬀect
is still unknown. In order to do research on this subject, it isnecessary to collect geomagnetic data of wider spatial coverageDiﬀusion ofmagnetic ﬁeld
Convection of
ﬂuid metal

and longer time span. Because the dynamo theory is applicableto generation of magnetic ﬁelds on other celestial bodies such asplanets and stars like the Sun, research on Geomagnetism isindispensable for studies of other astronomical bodies.
A schematic view of the geodynamo
Core The solid metal core of the Earth
Inner Core:
Outer Core
Core: The Earth’s liquid core made of Fe, Ni etc.

Inner
Core

Crust
Outer
Core

MantleInteraction between convective motions of liquid metal andthe existing geomagnetic ﬁeld generates new componentsof the geomagnetic ﬁeld [the dynamo eﬀect].
MantleMantle: A very thick (~2900km) layer of silicate rocks.
The geomagnetic ﬁeld originated from the outer corediﬀuses and decays away all through the mantle, which isstill observable at the surface.
Crust
Crust: A thin (at most several tens of kilometers) layer of crustal
rocks, on which we reside.

4

Geomagnetic field controllingthe near-Earth plasma
The space higher than the atmosphere is not a vacuum but

ﬁeld around the Earth prevents the solar wind to do so. This

ﬁlled with charged particles (i.e., electrons and ions). Suchcauses a formation of “magnetosphere” where no solar windmedium consisting of charged particles is called “plasma” . The

plasma directly enters. At polar region you can see aurora whengeomagnetic ﬁeld controls the motion of plasma. For example, if

substorm occurs; this is because variations of the geomagnetic

you put a strong magnet close to a CRT display, you will see

ﬁeld aﬀect motion of plasma particles around the Earth andimages on the display are distorted. This is because plasmacause precipitation of particles into the ionosphere.
As stated above, the geomagnetic ﬁeld is fundamental andbeams which make images on the display are bent by theindispensable parameter to study phenomena occurring in themagnetic ﬁeld of the magnet.
“Solar wind” , the supersonic plasma ﬂow f rom the Sunnear-Earth space. In the research ﬁeld of “space physics” , atoward the Ear th, is de viated around the Ear th without

number of researchers are utilizing the geomagnetic ﬁeld data.

penetrating directly to the atmosphere, because the geomagneticoc
shmagnetopause

e
av
kw

bo

w

Solar wind and magnetosphere

solar windradiation belts

ionospheresunauroral zone

Typical appearance of curtain-type aurora
Aurora in the picture looks like forming a stripe. This

from its underneath, rules of perspective will make you ﬁnd thatthe aurora seems to radiate from the center, changing its color

appearance is caused by electrons which are precipitation into thefrom red to green. Such aurora is called “corona-type aurora” .

atmosphere along the geomagnetic ﬁeld lines. If you see aurora(photo taken by Dr. Masatoshi Yamauchi at Kiruna, Sweden)5

2500 5AU

4

9

8

8-

8-

9-

WDC FOR GEOMAGNETISM, KYOTO
997+
5+
5- Kp

0
AL
(nT)
-2500
-5000

Significance of geomagnetic field researchfor society

500
ASY-D
0
ASY-H
(nT)
500

SC

The geomagnetic field strongly impacts society.
During magnetic storms which can be identified bymain phase

0
SYM-H
(nT)

large decrease of the geomagnetic field strength inrecovery phase

low latitudes, the radiation belt is developed, causing-500

frequent malfunction of man-made satellites. When

00

02

04 06

08

10

the polar geomagnetic field is disturbed strongly; that

12 14 16 18 20 22
OCT 29
UNIVERSAL TIME

00 02

04 06 08
OCT 3010

12

AE and ASY/SYM indices during geomagnetic storms, which have been derived
by the World Data Center for geomagnetism, Kyoto for more than 30 years.
The ASY/SYM indices indicate that the geomagnetic storm started from around
06 UT (universal time) on October 29, 2003, which was preceded by a sudden
increase of the geomagnetic field magnitude (SC). In the polar region a strong
substorm was initiated and the AE (AL) index showed a variation larger than 2500
nT (upper panel). In mid- and low-latitudes, the SYM index indicates that themagnetic storm was very intense (lower panel). During magnetic storms, theradiation belt (the Van Allen belt) consisting of high-energy particles is developed.

is, when substorms take place, an electric current is
induced over oil pipe lines and high-voltage powerlines, and then it happens that such infrastructure isd a m a g e d s e v e r e l y. I n o r d e r t o p r e d i c t s u c hphenomena, research related to “space weather
forecast ” is in progress in Japan, U.S., and othercountries. Geomagnetic field research is an importantfactor in daily lives.

Radiation
Outer Belt
Radiation
Inner Belt

High Energy
Proton / Electron

Earth
Sun

Geosynchronous
Orbit
Plasmasphere
Particle Injection
Magnetosheath

The geomagnetic field is important to delineate structure in
the Earth and detect its changes. Since volcanic eruptions andearthquakes change the Earth’ s structure, the geomagnetic fieldalso fluctuates accordingly. Attempts are being made to forecast
the eruptions and earthquakes using the geomagnetic field.
magnetic total fieldnorthern site

10 nT

southern site
91

92

93

94

95

96

97

98

Magnetic changes associated with the volcanic activity of
Nakadake, Aso Volcano. Correlated magnetic total field changes
are observed at north and south of the active crater. The inversed
polarity suggests an equivalent magnetic dipole beneath thecrater. Arrows indicate the periods of elevated volcanic activity,
corresponding to the periods of minimum magnetization of rocks
due to heat accumulation. Courtesy of Dr. Takeshi Hashimoto.

6Roles and Tasks of Data Analysis Center for Geomagnetism and Space Magnetism

Education

This center also constitutes a chair of Physics and Informatics of Natural Electromagnetic

Education at Graduate School

Environment that was defined as one of cooperative divisions to the Graduate Schoolof Science, Kyoto University. Through this division, this center contributes to graduate
education and supervises master’s and doctoral research of many graduate school students.

Solar-Planetary Electromagnetism
I, II

Subjects in the master course

Physical processes of the ionosphereand the magnetosphere as well as technical knowledge which is necessary in thecourse of study on electromagnetism in
the Earth are lectured in this subject byteaching staﬀ of this center and SolarPlanetary Electromagnetism Laboratory.

Seminar on Solar-Planetary
Electromagnetism II, III
Using English textbooks on SolarTerrestrial Physics, reading circles areformed by students in the master course,
while the teaching staﬀs serve as tutors.

Subjects in the doctor course
Seminar on Solar-Planetary Electromagnetism
II, III
Doctoral students are supervised
individually or by small groups according
to each research theme, and guided tocomplete their doctoral theses throughappropriate suggestions and/or discussion.

Faculty members of this center are in charge of the following subjects, in addition tosupervision of several undergraduates undertaking compulsory research programs forFaculty Education

graduation.

Subjects for undergraduates

Electromagnetism and Ionized Gas Dynamics
The elementary theory of magnetohydrodynamics and plasma physics is lectured
in this subject. The contents of the subject
will be necessary when you begin to learn
solar-terrestrial physics and geomagnetism.
Geomagnetism
Various disciplines of electromagnetismin the Earth are introduced by lecturing
how to measure/analyze the geomagnetic
ﬁeld, theory of geodynamo, paleomagnetism,and electromagnetic monitoring of crustal
movements. The basic theory of thosedisciplines is also given for further studying.

7

Exercise assignments of Earth andplanetary sciences

Speciﬁc data processing andsimulation using computers are assigned,in addition to practical exercises ofgeophysical ﬁeld works, for profoundunderstanding of what was lectured in“Geomagnetism” and “Electromagnetismand Ionized Gas Dynamics”.

Research assignments of Earthand planetary sciences
T1. Earth and planetary plasma
T2. Earth and planetary electromagnetic ﬁelds
Based on the acquired knowledge throughlectures of “Geomagnetism” and “Electromagnetismand Ionized Gas Dynamics”, speciﬁc research
assignments are given to each undergraduate ineither T1 or T2 of his/her choice. Both T1 andT2 aim at learning how to carry out each research
assignment by accumulating a research experienceat a real spot under supervision of teaching staﬀsof this center.

(As for details, you should refer to “Guidebook for Educational Aﬀairs” issued by
Graduate School of Science or “Subject Handbook” by Faculty of Science.)As an educational institution
Geomagnetic data and computer facilities indispensable to conduct researchand exercise are provided by this center for undergraduates and graduate school
students. As many as ten students visit this center daily.

Number of degrees awarded at this center
Since foundation of this center, 19 doctoral degrees and 44 master’s degrees
have been awarded under supervision of the teaching staﬀs at this center. These
alumni/alumnae are now playing active roles in each ﬁeld making use of theacquired technical knowledge.

Outreach activities
We also devote ourselves to illustrate latest scientiﬁc results and technicalknowledge in plain terms to the public. We have made the following feedback tocommunity so far:Commentaries of “WDC News”
Glossaries on this center’s web pages
Open campus
Seminars for high school students
Supply knowledge and materials to educators of geography
Participation in the editorial board of “Chronological Scientiﬁc Tables” of Japan
Participation in a special exhibition at the Kyoto University Museum (2008) etc.

90

270

0

180

Direction of
Geomagnetic Poles
Direction ofMagnetic PolesThe Earth isassociated with the geomagnetic ﬁeld that has an S(N)-pole ofa magnet near the North(South) Pole. A
magnetic compass, therefore, approximately
points toward the north. However, the pointing
direction is slightly diﬀerent from the true northby an angle called “declination”. Also, two pairsof poles can be deﬁned for the geomagnetic ﬁeld:
the geomagnetic poles and the magnetic poles.
The magnetic north corresponds to neither pole,since the geomagnetic ﬁeld actually has a more
complicated shape than a magnetic ﬁeld
generated by a bar magnet (See below).
Moreover, a magnetic needle suspended at a
center of balance does not keep horizontal. As arule, the N-pole dips downward by an angle

called “inclination” in the northernhemisphere.
The “geomagnetic poles” are the intersectionsof the Earth’s surface and the axis of a bar magnet
hypothetically placed at the center the Earth bywhich we approximate the geomagnetic ﬁeld.
There is such a pole in each hemisphere, and thepoles are called as “the geomagnetic north pole”
and “the geomagnetic south pole”, respectively.
On the other hand, “magnetic poles” are thepoints at which magnetic needles become vertical.
There also are “the magnetic north pole” and “themagnetic south pole”. The geomagnetic or
magnetic south(north) poles correspond to theN(S)-pole of a magnet. By the two sets ofdiagrams in the left, we show predicted locationsof the geomagnetic and magnetic poles by“International Geomagnetic Reference Field”(IGRF-10) from 1900 through 2010. These
poles are drifting according to slow and smoothchange in the geomagnetic ﬁeld called “thegeomagnetic secular variation”.
In the rightmost diagram, we show thepredicted declination at Kyoto in 2005 by IGRF10 in addition to the predicted directions towards
the geomagnetic and magnetic north poles. The
reason why we have now westward declination in
Japan is probably due to the presence of a strong
positive geomagnetic anomaly around Lake
Baikal in Siberia. The N-poles of magnetic
needles tend to be attracted to the anomaly toshow westward declinations around Japan.

8Roles and Tasks of Data Analysis Center for Geomagnetism and Space Magnetism

Services

Operation of World Data Center for
Geomagnetism, Kyoto
The worldwide Earth observation system was prepared as one of theInternational Geophysical Year projects in 1957. World Data Centers (WDCs)
were established as well in order to collect/distribute various data not tomentioning the geomagnetic data acquired by the newly prepared system. WDCs
are now being operated by research institutions (centers) in Japan, US, Russia,
Europe, China and so on.
In Japan, Data Analysis Center for Geomagnetism and Space Magnetism, aresearch institution of Graduate School of Science, Kyoto University is in charge of
operating the World Data Center for Geomagnetism, Kyoto.

Acquisition and preservation of data
As one of the WDCs, this center is now collecting/preserving data from world’s
geomagnetic observatories as many as approximately 400. The geomagnetic data
are transferred by postal mail, via geostationary satellites, or over the Internet.
Main preserved data are as follows:1848 - Present (Primarily 1957 and after)
Microﬁlm : ~9300, Microﬁche : ~10000, Magnetic Tape : ~1000,
Data book : ~3400, Geomagnetic Chart : ~80, Disk : ~10TB
Digital data : 1sec. values, 10sec. values, 1min. values, 2.5min. values,
Geomagnetic Field Data
1hour values(About 400 Geomagnetic
Analogue data : Normalrun magnetograms, Rapidrun magnetograms
Observatories)
Magnetic Index : AE, Dst, K Kp Kn Ks Km, Ap aa, ASY SYM indices
Geomagnetic Chart : Contour Chart
Magneto telluric Data 1hour values, normalrun tellurigrams, rapidrun tellurigrams
Satellite Magnetic Field Data IMP, MAGSAT, DE-1, DE-2, GOES, ETS-VI, Oersted, others
Solar, Interplanetary, Magnetosphere, Ionospheric Data
Miscellaneous Data

Data books and CD-ROMs issued by World
Data Center for Geomagnetism, Kyoto.

Change in the number of access to World Data Center for Geomagnetism, Kyoto.

Data distribution

800,000

Collected/preserved geomagnetic data are distributed to world’s
data users for free whenever requested. Data delivery on magnetic
media is declining. Instead, digital data transfer directly over theInternet is rising.
A number of access is incoming to our center everyday from allover the world via World Wide Web and anonymous ftp. As of
December, 2007, we have about 400,000 hits per month on our

Number of Access

Data distribution

Period of Data Collection
Media : Number of Volumes

600,000

400,000

200,000

web page.
0
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
01 07 01 07 01 07 01 07 01 07 01 07 01 07 01 07 01 07 01 07 01 07 01 07 01

Year/Month9Derivation and provision of geomagnetic index
The geomagnetic indices represent the degree of geomagnetic disturbanceand are very important for research in geomagnetism and space physics. In thiscenter we calculate three kinds of the geomagnetic indices, the AE indices, theDst index, and the ASY/SYM indices; and provide them free to the global
scientiﬁc community. (These three indices express geomagnetic disturbances at
diﬀerent latitudes. The AE indices are for disturbances in the auroral latitude,
while the Dst and ASY/SYM indicies are for the mid- and low-latitudes. The
Dst or the SYM index is a proxy for longitudinally symmetric disturbances, but
theHome page of this center

ASY

index

represents

longitudinal

asymmetryofgeomagnetic

disturbances.) We have been continually deriving and providing these[http://wdc.kugi.kyoto-u.ac.jp/]geomagnetic indices since 1981.
Considering this activity of this center, International Association of
Geomagnetism and Aeronomy (IAGA) and Science Committee On
Solar-Terrestrial Physics (SCOSTEP) adopted a resolution stating appreciation
for World Data Center for Geomagnetism, Kyoto seven times.
We have started to calculate the geomagnetic indices in real-time, because
geomagnetic ﬁeld data can be collected through the network and the space
weather prediction is now in progress. The real-time geomagnetic indices areprovided from our home page.

Geomagnetic field observation
We make observations of the geomagnetic ﬁeld at Mineyama, Kyoto andShigaraki, Shiga. The obtained data are processed in real-time and transferredto this center. The real-time data from Mineyama and Shigaraki can be browsed
from our home page or at LCD displays in this center.
We also installed magnetometers in Russia and collect the real-time
geomagnetic ﬁeld data by geosynchronous satellite communication or Internet.
Since the Russian data are needed in calculation of the AE indices, theDisplay of real-time observation data

scientiﬁc community hopes continuation and success of this project. Morerecently, the joint observation projects are proceeding with China, Turkey,
Thailand, Georgia, Peru, and other countries.

October 2003

Dst (Final)

WDC for Geomagnetism, Kyoto

(nT)
0
- 100
- 200
- 300
- 400
- 500

Mineyama observatory

1

6

11

16

21

26

31

Geomagnetic indices available from the home page
(Upper panel: AE indices, lower panel: Dst index)

10Roles and Tasks of Data Analysis Center for Geomagnetism and Space Magnetism

Research

80

Research on electric currents generated
by the ionospheric dynamo

60

L AT I T U D E

40

Cutting-edge results of this research topic are being given by making use of computer
simulation and data from satellite/radar observation. These results can be regarded as

20
0

-20

successors of many years of research eﬀorts on generation of ionospheric electric currents
having been conducted in Department of Geophysics. We have succeeded in conﬁrming-40

the presence of ﬁeld-aligned currents between the north and south hemispheres. The-60

currents originating from the center of Sq-current vortices have been theoretically

-80
0

4

8

16

12

predicted to exist but actually discovered by precise analysis of satellite geomagnetic data

20

24
LT

NP
summerconducted at this center.

Fig.1 The ﬁeld-aligned currents between the north and south Sq-vortices. The

dawn

presence of the currents was ﬁrst conﬁrmed by the Oersted magnetic

dusk

wintersatellite data. The equatorial EW magnetic component shows negative

SP

Fig.1

values on the dayside (the lowermost diagram on the left). Upperright: The simulated ﬁeld-aligned currents on the upper surface of theionosphere (the hatched regions indicate incoming currents). Lowerright: A schematic ﬁgure based on the simulation results. The magnetic
ﬁeld variations seen in the left diagrams can be explained by the electric
current system depicted in this ﬁgure.

Research on short-period variations ofgeomagnetic ﬁeld
Using both the geomagnetic ﬁeld data in high time-resolution and the solar
wind/magnetospheric data obtained by satellites, we have been studying various
types of geomagnetic pulsations and sudden commencement (SC) of geomagnetic

Fig.2

ﬁeld increase which is generated by compression of the magnetosphere due to

H-comp. (nT)(a)

shock waves in the solar wind. These phenomena can be understood by applying the

H-comp. (nT)magneto-hydrodynamic equations. We also identify Pi2 pulsations in an automated way
from the real-time geomagnetic ﬁeld measurements at 6 stations which are separated inlongitudinal direction. Results of detection of Pi2 pulsations are displayed at the home

H-comp. (nT)

H-comp. (nT)Fig.2 Global variations of the geomagnetic ﬁeld at SC
Mineyama
180

Kakioka

Teoloyucan

2

6

0

2

-2

2

80
70 York
60
60
300
APL 5040
Teoloyucan
30
0H-comp. (nT)..

Furstenfeldbruck

19:09

19:10

19:11

2006/02/23

York

0
-4
2
1

MLT=22.1hr at 21:29UT

Kakioka

0
-1

(c) 4

H-comp. (nT)

120

19:08

-2

-2
U T 21:24

240

11

MLT=20.9hr at 19:07UT

4

(b) 4

Fig.3

Fig.3 Real-time detection of Pi2 pulsations0-5

MLT=12.6hr at 19:07UT-4
U T19:03
19:04
19:05
19:06
19:07

page in almost real-time and this project contributes to the space weather prediction.

2006/05/21

Fuerstenfeldbruck
52

MLT= 6.3hr at 21:29UT
21:25

21:26

21:27

21:28

21:29

21:30

21:31

21:32

2006/04/21

APL

0
-2
-4
2
1

MLT=22.9hr at 04:05UTMineyama0-1-2
U T 04:01

MLT=12.9hr at 04:05UT
04:02

04:03

04:04

04:05

04:06

04:07

04:08

04:09

O
~

Research on magnetic storms and substorms
We are the ﬁrst in the world to simulate the electric current system during
geomagnetic storms by tracing charged particles in a realistic geomagnetic ﬁeld
model. This study intended to not only understand mechanisms of geomagnetic
storms/substorms but also predict them in a quantitative manner. We also achieved anumber of success by analysis of the geomagnetic indices.

Fig.4 Relation between geomagnetic storms and substorms, which was revealed
from analysis of the geomagnetic indices AE, ASY and SYM.
Fig.5 Result of tracing of charged particles during a magnetic storm

Fig.4

Fig.5

Electromagnetic research in the Earthand at the seaﬂoor
Geomagnetic data is very important as one of the observational means to delineate
the structure and dynamics in the Earth.

We are not only collecting/providing

data but also making use of the collected data in order to reveal the Earth’s deep
electrical conductivity structure that contributes to investigate the geodynamo process.
Furthermore, development of electromagnetic instruments and data analysis arebeing made in conjunction with a long-term electromagnetic observation project at
the seaﬂoor. The long-term geomagnetic data observed at the seaﬂoor deeper than
5,000m were open to the public through the WDC for Geomagnetism, Kyoto for theﬁrst time in the world, which is considered to be one of the most fruitful results of the
Photo.1

long-term observation project.

Photo.1 The newly developed “SeaFloor ElectroMagnetic Station (SFEMS)” justbefore launch from a research vessel. The station is equipped with an
Overhauser-type absolute scalar magnetometer and a ﬂuxgate-typevector magnetometer and capable of unmanned continuous operation foryears at the seaﬂoor.
Photo.2 Pin-point installation of SFEMS to the desired position at the seaﬂoor
by a submersible. Successive long-term observation is made possible byreplacement of SFEMSs. The metal arm in front is the submersible’ s
manipulator (by courtesy of ROV “Kaiko7000II”, JAMSTEC).
Photo.2

Research on structure and dynamics
of magnetosphere

Hydrogen60-120 keV

We are participating to the satellite project and contribute to data analysis,

Hydrogen27-60 keVcollection of magnetic ﬁeld and particle data, and creation of database. We discovered

Oxygen~160 keVa current system which has been unknown, and found an observational evidenceof existence of a current system which was predicted by previous researchers.
Moreover, analyzing high-energy particle data, we also discovered a relation which iscontradictory to the common sense between the geomagnetic ﬁeld variations and ring
current particles.
06

Fig.6 Temporal variations of energetic neutral atoms which were created from ring18

current particles (upper panel) and temporal variations of the SYM-H index
Fig.6

which is calculated by averaging the geomagnetic ﬁeld variations (lower
panel).

12

Research on methods of dataacquisition/services
We take part in realtime geomagnetic data acquisition over the globe which isindispensable for the sake of space weather forecast. We also in charge of studying
data transmission methods using the Internet, wireless transfer and communication
satellites’ relay function. It was not until these methods were put into practical usethat quasi-realtime service of geomagnetic indices was actually enabled.

Photo.3

Recently, we also concentrate on installation of magnetometers overseas and dataacquisition by those instruments. We are converting microﬁlms to digital imageﬁles and puts them online, since those microﬁlms contain a large volume of old
geomagnetic data.

Photo.3 Realtime data transmission by a combination of a commercial
communication satellite and the Internet (Atmospheric Science
Observatory at Phimai, Thailand).
Photo.4 All World Data Center meeting (May, 2007)
Photo.4

We actively participate in various international conferences in order todiscuss cooperation between data centers, promotion of data exchangeusing cutting-edge technologies and construction of databases.

Research on electromagnetic disturbanceof the Earth’s surface origin
Majority of the upper atmospheric phenomena such as auroras, geomagnetic storms
and pulsations are regarded of solar or solar-wind origin. It, however, turns out that
there exist geomagnetic pulsations excited by earthquakes, volcanic eruptions andtyphoons. Microbarometric variations are also observed at this center in addition toelectromagnetic ﬁelds, because those variations can be related to very low frequency

great earthquake oﬀ the Sumatra Island in 2004. The pulsations were
nT2/Hzobserved at Phimai Observatory, Thailand.
Fig.8 Common spectral peaks of microbarometric and geomagnetic oscillations.

MEM SPECTRA (Pressure-Shigaraki, Geomag.-Aso 2007 0821 UT 6:30-7:30)
Pressure

0.25
0.2
0.15
0.1
0.05
0
8
6

H-comp.

Anomalous geomagnetic pulsations discovered at the time of the

2

4
2
0

The pressure and geomagnetic data were observed at Shigaraki and Aso,
2nT /Hzrespectively.
Fig.8

1
0.8
0.6
0.4
0.2
0
100

D-comp.

Fig.7

Fig.7

hPa /Hzsound waves that interact with the upper atmosphere.

150

Research on the geomagnetic secular variation
We try to detect the geomagnetic secular variation with timescales of 100 – 1000
years from samples taken at archeological remains. Those timescales are considered
important for revealing the geodynamo eﬀect that is generating the geomagnetic ﬁeld
in the outer core of the Earth.

Photo.5

Measurements of remnant magnetization at an ancient remain of aﬁreplace (a roof tile kiln in the mid-7th century).
Photo.5

13

200

250
Period (sec)

300

350

400

Studies related to Graduate School of Science,
Kyoto University

Magnetic ﬁelds play fundamental roles everywhere in nature from the microscopic
world to the universe. Even in Graduate School of Science alone, to which thiscenter belongs, various natural magnetic ﬁelds are being explored. Since studies on
Geomagnetism and Space Magnetism share the basic principles with the following
disciplines, synergistic collaboration is possible by mutually exchanging usefulknowledge and information.

Eruption at the active crater of the Aso Volcano(by courtesy of Aso Volcanological Laboratory).

Research on geomagnetic changes
associated with volcanic activity
People at Institute of Geothermal Sciences are trying to delineate the relationshipbetween volcanic eruptions and the associated geomagnetic changes.

Research on the atmosphereof the thermosphere and the ionosphere
Telecommunication and precise positioning are aﬀected by various perturbation
caused by energy input from the magnetosphere to the atmosphere of thethermosphere and the ionosphere.
[http://stegps.kugi.kyoto-u.ac.jp/](By courtesy of Solar-Planetary Electromagnetism Laboratory.)
1.9
VA

Z/li

t= 28.16

At the Solar-Planetary Electromagnetism

Laboratory in Department of Geophysics, mechanisms for generation and propagationof atmospheric and plasmatic perturbations in the thermosphere and ionosphere areinvestigated using radio waves from GPS satellites and optical observations.

1.0

0.0

-1.0

-1.9
4.2
-0.10

-0.08

5.8
-0.06

-0.04

7.4
-0.02

X/li
0.00

9.0
0.02

10.6
0.04

0.06

12.2
0.08

0.10

Computer simulation of magnetic reconnection (by courtesyof Solar-Planetary Electromagnetism Laboratory)

Research on plasma in magnetospheresof the Earth and other planets
In the Solar-Planetary Electromagnetism Laboratory, research on characteristics ofplasmas in magnetospheres of the Earth and planets, and structures of magnetic ﬁelds
as well as their dynamics is conducted by computer simulations in addition to data
analyses of satellite and ground observations.

Research on phenomena on the Sun’s surface
It is well-known that the magnetic ﬁeld plays the essential role in plasma
phenomena on the Sun such as ﬂares. Kwasan and Hida Observatories of Graduate
School of Science are not only carrying out precise observation of the Sun’s surface but
also conducting theoretical studies by numerical simulations .

Active regions of the Sun (by courtesy of Hida Observatory).

14

Eizan RW.
Karasuma
ImadegawaDemachiyanagi

Kyoto City Subway
Tozai Line

Oike st.

to Umeda

Shijo
Kawaramachi

Shijo st.

Hankyu Line.

Higashioji st.

Marutamachi st.

Kawabata st.

Kamo river

Kawaramachi st.

Karasuma st.

Kyoto City Subway
Karasuma Line

Imadegawa

Kyodai
Nougakubu-Mae

HyakumanbenKeihan Line

Imadegawa st.

WDC forGeomag., Kyoto

Higashiyama
Sanjo

Kyoto Univ.

Higashiyama

Sanjo

Sanjo st.

JR Lineto Tokyo

Gojo st.

Shichijo st.
Kyoto
Stationto Nara

Kyoto
KintetsuLine
Kujo st.

Tohfukuji
toOsaka

to Osaka

Kitashirakawa-Oiwake, Sakyo, Kyoto 606-8502, JAPAN
Tel:+81-75-753-3929 Fax:+81-75-722-7884
URL: http://wdc.kugi.kyoto-u.ac.jp/