論文

査読有り
2014年12月

Long-term variation in the upper atmosphere as seen in the geomagnetic solar quiet daily variation

EARTH PLANETS AND SPACE
  • Atsuki Shinbori
  • ,
  • Yukinobu Koyama
  • ,
  • Masahito Nose
  • ,
  • Tomoaki Hori
  • ,
  • Yuichi Otsuka
  • ,
  • Akiyo Yatagai

66
1
開始ページ
1
終了ページ
20
記述言語
英語
掲載種別
研究論文(学術雑誌)
DOI
10.1186/s40623-014-0155-1
出版者・発行元
SPRINGER HEIDELBERG

Characteristics of long-term variation in the amplitude of solar quiet (Sq) geomagnetic field daily variation have been investigated using 1-h geomagnetic field data obtained from 69 geomagnetic observation stations within the period of 1947 to 2013. The Sq amplitude observed at these geomagnetic stations showed a clear dependence on the 10- to 12-year solar activity cycle and tended to be enhanced during each solar maximum phase. The Sq amplitude was the smallest around the minimum of solar cycle 23/24 in 2008 to 2009. The relationship between the solar F10.7 index and Sq amplitude was approximately linear but about 53% of geomagnetic stations showed a weak nonlinear relation to the solar F10.7 index. In order to remove the effect of solar activity seen in the long-term variation of the Sq amplitude, we calculated a linear or second-order fitting curve between the solar F10.7 index and Sq amplitude during 1947 to 2013 and examined the residual Sq amplitude, which is defined as the deviation from the fitting curve. As a result, the majority of trends in the residual Sq amplitude that passed through a trend test showed negative values over a wide region. This tendency was relatively strong in Europe, India, the eastern part of Canada, and New Zealand. The relationship between the magnetic field intensity at 100-km altitude and residual Sq amplitude showed an anti-correlation for about 71% of the geomagnetic stations. Furthermore, the residual Sq amplitude at the equatorial station (Addis Ababa) was anti-correlated with the absolute value of the magnetic field inclination. This implies movement of the equatorial electrojet due to the secular variation of the ambient magnetic field.

Web of Science ® 被引用回数 : 14

リンク情報
DOI
https://doi.org/10.1186/s40623-014-0155-1
Web of Science
https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000348393700001&DestApp=WOS_CPL
URL
http://www.scopus.com/inward/record.url?eid=2-s2.0-84919903895&partnerID=MN8TOARS
URL
http://orcid.org/0000-0001-5363-3870
ID情報
  • DOI : 10.1186/s40623-014-0155-1
  • ISSN : 1880-5981
  • ORCIDのPut Code : 20672195
  • SCOPUS ID : 84919903895
  • Web of Science ID : WOS:000348393700001

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