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地磁気センターニュース



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地磁気世界資料解析センター News No.82 2003年11月30日
 
 
1.新着地磁気データ
 
      前回ニュース(2003年9月30日発行, No.81)以降入手、または、当センターで入力したデータの
  うち、主なものは以下のとおりです。オンライン利用データの詳細は
  (http://swdcwww.kugi.kyoto-u.ac.jp/catmap/index-j.html) を、観測所名の省略記号等については、観測所カ
  タログ(http://swdcwww.kugi.kyoto-u.ac.jp/catmap/obs-j.html) をご参照ください。
  また、先週の新着オンライン利用可データは、
  (http://swdcwww.kugi.kyoto-u.ac.jp/wdc/onnew/onnew-j.html)で御覧になれます。
 
 
      Newly Arrived Data
        (1)Annual Reports and etc.
                 SOD, OUJ, HAN, NUR(Sep.- Oct., 2003), AQU(2002), LRV(2002), NGK (Sep., 2003)
 
 
        (2)Digital Data
          オンライン利用データカタログ (http://swdcwww.kugi.kyoto-u.ac.jp/catmap/index-j.html)
	 及び新着オンライン利用可データ
         (http://swdcwww.kugi.kyoto-u.ac.jp/wdc/onnew/onnew-j.html) をご参照願います。
 
 
        (3)Kp index: (http://swdcwww.kugi.kyoto-u.ac.jp/kp/index-j.html)
                 Sep. - Oct., 2003
 
 
 2.1時間値Dst指数とASY/SYM指数
 
      Quick Look Dst指数(http://swdcwww.kugi.kyoto-u.ac.jp/dstdir/dst1/quick.html) および Quick Look AE
  指数 (http://swdcwww.kugi.kyoto-u.ac.jp/aedir/ae/quick.html) は1日以内の遅れで当センターのホームペー
  ジから利用できます。
 
 
3.21世紀COEプログラムへの参加とCOE外国人研究員の着任
 
  今年度採択の京都大学21世紀COEプロジェクト『活地球圏の変動解明 -アジア・オセアニアから
世界への発信- 』(代表:余田成男 理学研究科教授)への取り組みの一部として、当センターが中心と
なり、このプロジェクトのポータルサイトの構築を推進することになりました。現在はまだ仮のホーム
ページ
http://swdcft49.kugi.kyoto-u.ac.jp/kagi/index_j.htm を立ち上げたばかりですが、その英語ページの担当およ
び電磁気的手法を用いた活地球圏科学研究推進のため、オーストラリア出身のヘザー・マクレイディ博士
が11月から着任しました。研究室は地磁気センター内にあり、このCOEプロジェクトに密接に関連
する地磁気センターの活動にも一部参加しています。
 
 
4.COE外国人研究員自己紹介−Dr. Heather McCreadie, COE Research Fellow
 
  I started my career at Latrobe University, Melbourne, Australia where I obtained an undergraduate degree in
Geology and Physics. After a brief stint in the gold mining industry, I returned to Latrobe University to complete an
 Honours degree in physics. It was in this year I was introduced to geomagnetism. Under the aegis of Dr. Eric
Butcher I researched the topic of abnormal quiet days in Sq. This whetted my appetite for the subject and I
continued with my studies, this time working on the annual and semiannual variations in night-time, ground-based
geomagnetic observatory data. This work allowed me to be admitted to the degree of Doctor of Philosophy
(physics). Thereafter, I worked with Dr. Elizabeth Essex in the field of GPS occultations using the FedSat satellite.
This involved modeling the orbit of the satellite with respect to areas of dense TEC. My next move was to AGSO,
now known and Geoscience Australia in Canberra. There I worked under the aegis of Dr. Charles Barton. Here I
came into contact with magnetic instruments for the first time. I was in charge of Gnangara and Learmonth
magnetic stations in Western Australia . I contributed to the Kp index valuations, instrument observations and
recovery, and the repeat station survey. I was also a delegate for the Australian Disaster Information Network. This
allowed me to understand how scientists, engineers and lay persons needed to interact with each other in order to
evaluate recovery and prevention techniques for any type of large scale disaster. I felt I needed to see the world so I
then moved on to work as a research scientist at GeoForschungsZentrum in Potsdam, Germany.  The CHAMP
satellite had just been launched and the data beckoned to be studied. Under the aegis of Prof. Volker Haak I
worked on data from the Overhauser magnetometer and the vector magnetometer on board CHAMP. My own
project was in the area of the equatorial electrojet and the Sq system and I worked on induction in mantle using
thesatellite data with a group headed by Prof. Multi Zdenek Martinec from the University of Prague. Currently, I
am employed by the COE project “Elucidation of the Active Geosphere” at the University of Kyoto.
If you have any questions or just feel like chat, feel free to come and visit me any time.
 
My computer alias is bilby. Many people ask me, “What is a bilby?” They are a rabbit size marsupial with large
ears and their fur is soft grey with a bluish tinge. A long pointed snout and a large black and white tail with a
white brush tip makes this a striking looking animal. Strong claws enables this marsupial to burrow quickly
through sandy soil and the bilby’s pouch faces backwards. Size wise they range from 30 to 60 cm in length with
roughly a 20cm tail. They live in Australia and are an endangered species, just like me.
 
 
        
< A Macrotis Lagotis           < Hmmm?>
  otherwise known as a Bilby>
 
 
5.Geoeffectiveness of Intense Solar events                                            (Sobhana Alex)
 
     The tenuous atmosphere of the Sun undergoes sudden and dramatic changes. Solar flare is one of the
important phenomena, which occurs due to the sudden release of the magnetic energy built up in the solar
atmosphere in a spontaneous manner. This process results in the emission of intense energies in the entire
wavelengths spanning from radio waves to X-rays and gamma rays. X-ray radiations of intense energies produce
their effect on the ground magnetic records as a sporadic increase in the earth’s magnetic field within few minutes
of the flare occurrence on the Sun. Solar activity and the physics of Sun-earth interaction process has been a topic
of immense importance in the last three decades, due to its impact on advancement in technological applications.
Solar cycle 23 had its maximum peak during the years 2000-2001. Close correspondence between the
occurrence frequency of solar flares and solar activity is well known, as the sunspots are visible in regions of high
magnetic field strengths. However, the recent eruptions occurred from the tenuous atmosphere of the Sun seemed
to produce flares of strikingly large magnitude and unleashing billions of tons of charged particles of enormous
speed, towards the last week of October 2003. As was observed and reported by solar observers, development of
several spots started becoming visible from 24 October 2003. From October 24, a Jupiter sized giant sunspot 486
became an active one to produce a major flare of X17 magnitude on October 28.  This blast on 28 October,
unleashed billions of tons of electrically charged particles barreling into space toward Earth, as a cloud of hot
electrified gas, streaming with speed greater than 2000 km/sec (5 million mph). These solar ejecta produced a
geomagnetic storm on October 29, within 19 hours of the energy release. As suggested by Dr. Kappenman , the
coupling process between the Sun-earth was quite weak , allowing the interaction of the Interplanetary Magnetic
Field( IMF) with the earth’s magnetosphere for almost one third of its passage time through the earth. Subsequent
to this dynamic exprosive event, more than a dozen X - class flares were reported. Coronal masss ejections of
predominant strength in the months of October and November 2003 and subsequent storm occurrences have posed
problem among the space scientists concerning  the understanding of the energy transfer process from Sun to
Earth through the interaction of the Interplanetary Magnetic Field and the magnetosphere of the earth.
     Some of the basic physics on the geomagnetic storm phenomenon could be explained from the recent
investigation reported by the scientists G.S.Lakhina and S.Alex of Indian Institute of Geomagnetism, India in
collaboration with the scientists Bruce Tsurutani, Jet Propulsion Laboratory, USA and Walter Gonzalez , INPE,
Brazil. This work has brought out the characteristics of the geomagnetic storm that happened 144 years ago in
September 1-2, 1859 , as deciphered from the manual observations of the geomagnetic field from the
Colaba/Mumbai (Geomag.Lat.9.87°N; Long. 142.7°E) magnetic observatory. The magnetic data for this event has
been recently calibrated and deduced from the measurements of the Horizontal magnetic field from the Grubb
magnetometer for hourly intervals prior to the storm beginning and 15 minutes intervals during the disturbed period
of the event.
     The occurrence feature and the magnitude of the storm of 1-2 September 1859, as evidenced from the low
latitude magnetic measurements at Colaba, has close relevance to the observations and the suggestions based on the
report of the first ever recorded, solar flare observations, by Carrington in 1859 and Hodgson in 1859, in the
Monthly Notices of the Royal Astronomical Society of astronomical literature. It was shown that the time delay of
the storm beginning associated with the Carrington solar flare and as stated in Carrington’s report of 17 hour 40
minutes has matched well with the storm record at Colaba. The magnetic field decrease in the Horizontal
component at Colaba was ~ -1600 nT.
       Thus comparing the impact time and the magnitude of the super storms, which occurred almost 144 years
  ago and the recent geomagnetic storm event of October 29, 2003, the variable nature of the storm intensity
has created certain unanswered problems. The paradigm on whether the solar activity is the key parameter or the
magnetic field characteristics within the energy release from the Sun judge the extent of its geoeffectiveness? Thus
a combined investigation of statistical nature based on the ground based magnetic data for extended time periods
and the available interplanetary and solar observations is the need of the time to improvise the knowledge of the
space weather aspects of highly energetic solar events.
 
  

Quick look digital magnetie record of the three components H, D and Z, recorded and transmitted from Alibag Manetic Observatory (Geomag Lat. 10.03 °N, Long. 146°E) on the storm day , October 29, 2003. Multiple step storm is evident during the main phase. <紹介>  Prof. Sobhana Alex は、インド地磁気研究所の観測およびデータ解析部門の責任者で、11月26日から 12月9日まで、IAGAのプロジェクトの一つである地磁気観測古記録の保存(Old Magnetogram Rescue)の関係で、そのプロジェクト推進の中心となっている当地磁気センターを訪問し、マグネトグラ ムのディジタル画像化などについて、打ち合わせを行っています。


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