1997: No. 41 [Jan], No. 42 [Mar], No. 43 [May], No. 44 [Jul], No. 45 [Sep], No. 46 [Nov]
1998: No. 47 [Jan], No. 48 [Mar], No. 49 [May], No. 50 [Jul], No. 51 [Sep], No. 52 [Nov]
1999: No. 53 [Jan], No. 54 [Mar], No. 55 [May], No. 56 [Jul], No. 57 [Sep], No. 58 [Nov]
2000: No. 59 [Jan], No. 60 [Mar], No. 61 [May], No. 62 [Jul], No. 63 [Sep]
★地磁気センターニュース No.64／ 2000年11月27 日★
１．新着地磁気データ
前回ニュース（2000年9月27日発行, No.63）以降入手、または、当センターで入力したデータ
の内、主なものは以下のとおりです。（観測所名の省略記号等については、データカタログ
（http://swdcdb.kugi.kyoto-u.ac.jp/catmap/obs-j.html) をご参照ください。）
Newly Arrived Data
（１）Analogue Data
Annual Reports and etc.:
NGK(Aug.-Oct. 2000), Finnish Obs.(HAN,NUR,OUJ,SOD, Sep.2000)
French Obs.(CLF,BNG,MBO,DRV,PAF,KOU,PPT,AMS, 1997)
TSU(1999), VSS(1999), SYO(1999)
（２）Digital Data
Geomagnetic Hourly Values: (http://swdcdb.kugi.kyoto-u.ac.jp/hyplt/index-j.html)
HTY(Jul.-Aug. 2000), LNP(Dec.1999-Aug.2000), DIK(1995), BSL(Jan.-Mar.1986, 1993-98)
PST*(1994-98), NVS(1996-99), KAK,MMB,KNY(Sep.2000), AQU(1995-98), ASC*(1994-99)
CLF(1936-40), HYB(1985-89), TSU(1977-94), WIK(1994,97), DOU(1999), DVS(1998-99)
BOU,BRW,CMO,DLR,FRD,GUA,HON,NEW,SIT,SJG,TSC(1993-98)
HRN(1994-98), LER(1983-85), TAN(1998)
Geomagnetic 1 Minute Values: (http://swdcdb.kugi.kyoto-u.ac.jp/mdplt/index-j.html)
HTY(Jul.-Sep. 2000), VAL(Sep.2000), ASC*(1994-99), PST*(1994-98), HBK(1972-73)
KAK,MMB,KNY(Sep.2000), LNP(Dec.1999-Aug.2000)
Geomagnetic 1 Second Values: (http://swdcdb.kugi.kyoto-u.ac.jp/shplt/index-j.html)
KAK,MMB,KNY(Sep.2000), HTY(Jul.-Sep.2000)
（３）Kp index: (http://swdcdb.kugi.kyoto-u.ac.jp/kp/index-j.html)
Kp-Index Table(Sep.-Oct. 2000)
（４）Magnetogram digital image files: (http://swdcdb.kugi.kyoto-u.ac.jp/film/index-j.html)
MMB(Rapid-run, 1984-97), BNG(normal-run, 1985)
＊新観測所 ASC Ascension Island GGlat.=-7.95, long.= 345.62, Gmlat.= -47.49
PST Port Stanley GGlat.=-51.70, long.= 302.11, Gmlat.= -41.49
２．一時間値Dst指数の算出と配布・１分値ASY/SYM指数の算出
2000年7 月〜9月のDst指数(Provisional)を算出し、関係機関に配布しました。ご希望の方は、郵便または
ファクシミリにて、京都大学大学院理学研究科地磁気世界資料解析センターまでお申し込み下さい。なお、
Quick Look Dst指数 (http://swdcdb.kugi.kyoto-u.ac.jp/dstdir/)および Quick Look AE指数
(http://swdcdb.kugi.kyoto-u.ac.jp/aedir/ae/quick.html) は2〜3日の遅れで当センターのホームページから利用できます
また、2000年9月までの１分値ASY/SYM指数を算出しホームページに載せました。
３．Auroral and Geomagnetic Research in Denmark
2000年10月8 日から13日まで当センターに滞在されたデンマーク気象研究所のPeter Stauning氏(Pst@dmi.dk)
にデンマークでのオーロラ・地磁気研究についての記事を書いていただきました。
Professor H. C. Oersted and the Oersted Satellite
The first Danish satellite, Oersted, launched 23 February 1999, has now been in orbit for almost two years and is
still functioning well. The satellite is a high-precision geomagnetic research mission with strong international
cooperation. The satellite is named after the Danish professor Hans Christian Oersted (1777-1851), who in 1820
observed and reported that electrical currents in a wire would cause deflection of a compass needle. Thus, he
became the discoverer of electromagnetism. H. C. Oersted further, in 1826, explained the magnetic variations
associated with auroras by postulating the existence of electric currents in the upper atmosphere along the arcs.
While at that time a revolutionary idea, such currents are now commonly named auroral electrojets. Professor
Oersted, since 1829 director of the Danish Polytechnical University, founded the first geomagnetic observatory in
Denmark. Routine observations started from Copenhagen in 1842 and were continued at this site for more than 20
years.
Auroral Research at Danish Meteorological Institute
The brilliant works of Oersted initiated a strong interest in geomagnetic and auroral research in Denmark. Systematic
observations of auroras from Godthaab conducted during 1865 to 1880 by Samuel Petrus Kleinschmidt (1814-1886)
were analyzed for the Danish Meteorological Institute (DMI) by Sophus Tromholt (1851-1896). These observations
showed that the frequency of auroras at very high latitudes decreased during times of high sunspot number [Tromholt,
1882]. Tromholt concluded correctly, that the auroral region was limited in latitude and moved equatorward during
strong solar activity. He also noticed that the frequency of auroras at these high latitudes were higher during the day
hours than during night. This pioneering observation is a consequence of the now well-known shape of the auroral
oval being located at higher latitudes at day than at night.
An expedition headed by Adam Paulsen (1833-1907) was sent to Godthaab, Greenland, by the Danish
Meteorological Institute during the First International Polar Year 1882/83 to establish a geophysical observatory for
meteorological and auroral studies. Adam Paulsen tried to estimate the height of auroras near Godthaab by using
triangulation on simultaneous observations of the lower border of auroral arcs from two observatories separated by
5.8 km. Heights were estimated for 22 auroras and were found to range from 0.6 km to 68 km [Paulsen, 1893,1894].
Now we know that these results the first of their kind were wrong, since auroras are newer observed below 60
km by reliable techniques. Adam Paulsen also observed the deflections of a compass needle during auroral activity
and discussed the existence of horizontal as well as vertical electrical currents associated with auroras. He combined
the auroral investigations into an auroral "ray" theory [Paulsen, 1894, 1896] where he postulated that the auroral
emissions were created by excitation of air molecules by invisible "cathode rays" emitted from a negative electrode in
space - a result not far from modern auroral concepts since two years later J.J. Thomson (England) discovered that
the cathode rays were actually electrons.
DMI Auroral Expeditions to Iceland and Finland
Adam Paulsen was director of the Danish Meteorological Institute from 1884 to 1907. In 1899 he arranged an auroral
expedition to Akureyri at the north coast of Iceland to observe the spectra of auroral emissions and investigate the
relations between atmospheric electricity and auroras. With the expedition was also a young physicist, Dan Barfod la
Cour (1876-1942), who was responsible for the spectrographic observations and an artist painter, Harald Moltke
(1871-1960), with the task to provide color reproductions of the observed auroras. A year later a similar expedition
now headed by la Cour and also including Moltke was sent by DMI to Northern Finland to conduct further auroral
observations.
The scientific results from the two expeditions were remarkable. Adam Paulsen reported the detection of 16 not
previously observed lines in the ultraviolet part of the auroral spectrum [Paulsen, 1900,1901]. An accurate scaling of
these lines showed that they came from oxygen and nitrogen emissions which supported Paulsens theory on the
excitation of the air molecules by invisible cathode rays. But the works by Harald Moltke were perhaps even more
remarkable. He produced a set of beautiful oil color paintings of auroras possibly the finest reproductions of
auroras ever made. The original paintings are kept by the Danish Meteorological Institute but reproductions have been
given to numerous observatories and institutions all over the world.
An example of Moltkes paintings is displayed in the figure. In the background of the painting the characteristic
mountain ridges near Akureyri are displayed. In the foreground on a pedestal is shown the spectrograph. The
instrument comprises a prism to refract the auroral light that enter through a narrow slit at the front. A lens system
focuses the refracted image of the slit onto a photographic plate mounted at the rear of the instrument. Since different
wavelengths are refracted differently by the prism, a series of narrow lines are produced at the photographic plate,
one for each characteristic component of the detected light. The instrument is still held by the DMI.
On the sky in the upper part of the painting a vivid display of curly break-up auroral arcs is seen. It is a quite
natural-looking reproduction. When observing the aurora (in darkness), Harald Moltke sketched the shape on cartoon,
and noted the colors, movements and other characteristics of the aurora as well as the view direction and the time. In
daylight the following morning he painted most carefully the observed auroral display guided by his sketches and
notes.
Auroral Research at DMI after 1901
The auroral research continued at DMI after the two successful expeditions. Due to the director's strong interest in
auroral observations the weather stations, operated by the Danish Meteorological Institute, have for many years (from
1897) conducted routine observations of auroras in Denmark [e.g., Egedal, 1938], and later also in Greenland. During
1952-56 Knud Lassen, at that time manager of the Geomagnetic Observatory in Godhavn, conducted intense auroral
observations from Godhavn. These observations provided the material for the first comprehensive analysis of auroral
activity in the polar cap [e.g., Lassen, 1959, 1961, 1963]. Lassens work on polar cap auroras was later extended by
Christian Danielsen on basis of observations from Thule [Danielsen, 1969]. The auroral observations from Denmark
and Greenland were intensified during the IGY 1957/58 [Lassen et al., 1964] and extended by photographic
recordings using all-sky camera instruments installed on several stations in Greenland. During 1970-80 up to 6 all-sky
camera stations covering a substantial fraction of the northern polar cap were operated in Greenland by the DMI.
Since 1990 these stations have all been closed.
Geomagnetism at DMI
The geomagnetic observations in Denmark, initiated by H. C. Oersted, were in 1891 resumed from an observatory
established in Copenhagen by the Meteorological Institute. With the advent of electrical tramways the disturbances in
Copenhagen became excessive and a new observatory and magnetic laboratory was established in Rude Skov north of
Copenhagen in 1907. At this location an era of highly skilled magnetic instrument developments started.
The work was initially headed by Adam Paulsen himself. In 1920 Dan B. la Cour was appointed head of the Division
of Geomagnetisme. From 1923 to 1942 he was also director of the DMI. La Cour was a brilliant instrument
constructor and developed with assistance from Viggo Laursen and Johannes Olsen (1894-1991) several types of
magnetic precision instruments which came in use at hundreds of observatories all over the world. Among other the
Quartz Horizontal-Force Magnetometer (QHM) and the Magnetometric Zero Balance (BMZ) instrument for absolute
measurements of the horizontal and vertical components, respectively. They, furthermore, developed the la Cour
variograph for recordings of relative variations in the three magnetic components. The instrument uses a focused light
beam reflected at mirrors mounted at small magnets either suspended on torsioned quarts fibre (horizontal
components) or installed on a balance (vertical component) to produce traces on a photographic plate mounted at a
rotating cylinder. The deflections of the traces from a marked baseline are proportional to the geomagnetic variations.
These instruments were built in large quantities and high quality for sale from the DMI and have been standard
observatory instruments through several decades of worldwide geomagnetic observations. The magnetometry work at
DMI has been carried on by Emil Kring Lauridsen, Ole Rasmussen and Michel Genevey, who have developed and
produced for sale modern flux-gate magnetometers of superior quality.
International Polar Geomagnetic Observations
La Cour worked intensely for the preparation of the meteorological, geomagnetic and auroral observations to be
conducted from a large number of temporary stations in both the northern and southern polar regions at the 50 year
anniversary for the first polar year (1882/83). He became President for the Commission for the Second International
Polar Year 1932/33. The second polar year was a great accomplishment and la Cour and his colleague Viggo Laursen
worked hard to make the numerous observations made during the polar year available to the international community.
In recognition of his extensive contributions la Cour was in 1936 elected President of the International Union for
Geodesy and Geophysics (IUGG) He held that position until his death in 1942. His co-worker, Viggo Laursen,
compiled in 1950 the more than 1000 publications resulting from the polar year. He also was an active officer of
IUGG, was vice-president during 1957-60 and became its President during 1960-63. As a result of Viggo Laursens
efforts for the International Geophysical Year (IGY) in 1957/58 one of the four World Data Centers for
Geomagnetism, WDC-C1, was placed at the Danish Meteorological Institute.
DMI Geomagnetic Observations from Greenland
Dan B. la Cour, while being director of the DMI, established a geomagnetic observatory in Godhavn, Greenland to
continue the polar geomagnetic observations started by Adam Paulsen. The observatory buildings were completed in
1925 75 years ago. Routine observations started on 1 February 1926.
During the IGY three geomagnetic observatories were in operation in Greenland, at Thule close to the geomagnetic
pole, at Godhavn, and at Julianehaab (later moved to Narsarsuaq), and pioneering research resulted from the polar
magnetic observations. Leif Svalgaard, manager of the Geomagnetic Observatory in Thule, noticed that the vertical
component of the magnetic field at Thule displayed either of two different characteristic patterns for the variations
during the day. This feature, now named the Svalgaard-Mansurov effect, is due to the consistent toward/away
direction of the interplanetary magnetic field within a solar wind sector [Svalgaard, 1973].
On initiative from Johannes Wilhjelm and Eigil Friis-Christensen the geomagnetic observations from Greenland has
since 1972 been extended by establishing temporary variation stations along the west coast of Greenland. The array
of variometer stations was later further extended to the east coast of Greenland and to the ice cap. At present 3
permanent (absolute measuring) and 15 temporary (variation) magnetic observatories are operated in Greenland
stretching from the auroral zone to the magnetic pole. They form the most comprehensive array of geomagnetic
observatories existing in the polar regions and have supplied data for hundreds of scientific publications. They now
provide a most useful support of the Oersted geomagnetic research mission.
The references quoted may be found at the web address:
http://www.dmi.dk/fsweb/soljord/nordlys_forsk/nordlys_publ.html
A catalog of Harald Moltke's auroral paintings may be found at the sites:
http://www.dmi.dk/dmi/jubilaeum/island.html
http://www.dmi.dk/dmi/jubilaeum/finland.html