Magnetic local time dependence of geomagnetic disturbances contributing to the AU and AL indices

• Tomita, S.

• Nosé, M.

• Iyemori, T.

• Toh, H.

• Takeda, M.

• Matzka, J.

• Bjornsson, G.

• Saemundsson, T.

• Janzhura, A.

• Troshichev, O.

• Schwarz, G.

Abstract

The Auroral Electrojet (AE) indices, which are composed of four indices (AU, AL, AE, and AO), are calculated from the geomagnetic field data obtained at 12 geomagnetic observatories that are located in geomagnetic latitude (GMLAT) of 61.7°–70°. The indices have been widely used to study magnetic activity in the auroral zone. In the present study, we examine magnetic local time (MLT) dependence of geomagnetic field variations contributing to the AU and AL indices. We use 1-min geomagnetic field data obtained in 2003. It is found that both AU and AL indices have two ranges of MLT (AU: 15:00–22:00 MLT, ~06:00 MLT; and AL: ~02:00 MLT, 09:00–12:00 MLT) contributing to the index during quiet periods and one MLT range (AU: 15:00–20:00 MLT, and AL: 00:00–06:00 MLT) during disturbed periods. These results are interpreted in terms of various ionospheric current systems, such as, Sq[p], Sq, and DP2.

Journal

• Annales Geophysicae

  Annales Geophysicae 29 (4), 673-678, 2011-04-14

  European Geosciences Union

Keywords

• Space and Planetary Science
• Earth and Planetary Sciences (miscellaneous)
• Atmospheric Science
• Geology
• Astronomy and Astrophysics

Details

• CRID: 1050001335810775808
• NII Article ID: 120005593634
• NII Book ID: AA10731540
• ISSN: 09927689
• ISSN: 14320576
• DOI: 10.5194/angeo-29-673-2011
• HANDLE: 2433/197214
• Web Site: https://angeo.copernicus.org/articles/29/673/2011/angeo-29-673-2011.pdf
• Text Lang: en
• Article Type: journal article
• Data Source:
  • IRDB
  • Crossref
  • CiNii Articles
  • KAKEN