Simultaneous observation of auroral substorm onset in Polar satellite global images and ground-based all-sky images

• 能勢, 正仁

  Institute for Space-Earth Environmental Research, Nagoya University

• Kauristie, Kirsti

  Finnish Meteorological Institute, Helsinki

• Nishimura, Yukitoshi

  Department of Atmospheric and Oceanic Sciences, University of California･Department of Electrical and Computer Engineering and Center for Space Physics, Boston University

• Miyashita, Yukinaga

  Korea Astronomy and Space Science Institute

• Frey, Harald U.

  Space Sciences Laboratory, University of California

• Juusola, Liisa

  Finnish Meteorological Institute, Helsinki

• Whiter, Daniel

  School of Physics and Astronomy, University of Southampton

• Nosé, Masahito

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

• Fillingim, Matthew O.

  Space Sciences Laboratory, University of California

• Honary, Farideh

  Space and Planetary Physics, Lancaster University

• Rogers, Neil C.

  Space and Planetary Physics, Lancaster University

• Miyoshi, Yoshizumi

  Institute for Space-Earth Environmental Research, Nagoya University

• Miura, Tsubasa

  Institute for Space-Earth Environmental Research, Nagoya University

• Kawashima, Takahiro

  Institute for Space-Earth Environmental Research, Nagoya University

• Machida, Shinobu

  Institute for Space-Earth Environmental Research, Nagoya University

抄録

Substorm onset has originally been defined as a longitudinally extended sudden auroral brightening (Akasofu initial brightening: AIB) followed a few minutes later by an auroral poleward expansion in ground-based all-sky images (ASIs). In contrast, such clearly marked two-stage development has not been evident in satellite-based global images (GIs). Instead, substorm onsets have been identified as localized sudden brightenings that expand immediately poleward. To resolve these differences, optical substorm onset signatures in GIs and ASIs are compared in this study for a substorm that occurred on December 7, 1999. For this substorm, the Polar satellite ultraviolet global imager was operated with a fixed-filter (170 nm) mode, enabling a higher time resolution (37 s) than usual to resolve the possible two-stage development. These data were compared with 20-s resolution green-line (557.7 nm) ASIs at Muonio in Finland. The ASIs revealed the AIB at 2124:50 UT and the subsequent poleward expansion at 2127:50 UT, whereas the GIs revealed only an onset brightening that started at 2127:49 UT. Thus, the onset in the GIs was delayed relative to the AIB and in fact agreed with the poleward expansion in the ASIs. The fact that the AIB was not evident in the GIs may be attributed to the limited spatial resolution of GIs for thin auroral arc brightenings. The implications of these results for the definition of substorm onset are discussed herein.

収録刊行物

• Earth, Planets and Space

  Earth, Planets and Space 70 2018-05-04

  Springer Nature

キーワード

• Substorm
• Auroral breakup
• Aurora
• Substorm onset
• Global images
• All-sky images

詳細情報

• CRID: 1050001338207801472
• NII論文ID: 120006537089
• ISSN: 18805981
• DOI: 10.1186/s40623-018-0843-3
• HANDLE: 2433/235015
• Web Site: http://link.springer.com/content/pdf/10.1186/s40623-018-0843-3.pdf
• Web Site: http://link.springer.com/article/10.1186/s40623-018-0843-3/fulltext.html
• 本文言語コード: en
• 資料種別: journal article
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