論文

査読有り 筆頭著者 本文へのリンクあり 国際誌
2021年1月

Temporal evolutions of N2+ Meinel (1,2) band near 1.5 μm associated with aurora breakup and their effects on mesopause temperature estimations from OH Meinel (3,1) band

Earth, Planets and Space
  • Takanori Nishiyama
  • ,
  • Makoto Taguchi
  • ,
  • Hidehiko Suzuki
  • ,
  • Peter Dalin
  • ,
  • Yasunobu Ogawa
  • ,
  • Urban Brändström
  • ,
  • Takeshi Sakanoi

73
30
記述言語
英語
掲載種別
研究論文(学術雑誌)
DOI
10.1186/s40623-021-01360-0
出版者・発行元
SpringerOpen

We have carried out ground-based NIRAS (Near-InfraRed Aurora and airglow Spectrograph) observations at Syowa station, Antarctic (69.0°S, 39.6°E) and Kiruna (67.8°N, 20.4°E), Sweden for continuous measurements of hydroxyl (OH) rotational temperatures and a precise evaluation of auroral contaminations to OH Meinel (3,1) band. A total of 368-nights observations succeeded for two winter seasons, and three cases in which N2+ Meinel (1,2) band around 1.5 μm was significant were identified. Focusing on two specific cases, detailed spectral characteristics with high temporal resolutions of 30 seconds are presented. Intensities of N2+ band were estimated to be 228 kR and 217 kR just at the moment of the aurora breakup and arc intensification during pseudo breakup, respectively. At a wavelength of P1(2) line ( ∼ 1523 nm), N2+ emissions were almost equal to or greater than the OH line intensity. On the other hand, at a wavelength of P1(4) line ( ∼ 1542 nm), the OH line was not seriously contaminated and still dominant to N2+ emissions. Furthermore, we evaluated N2+ (1,2) band effects on OH rotational temperature estimations quantitatively for the first time. Auroral contaminations from N2+ (1,2) band basically lead negative bias in OH rotational temperature estimated by line-pair-ratio method with P1(2) and P1(4) lines in OH (3,1) band. They possibly cause underestimations of OH rotational temperatures up to 40 K. In addition, N2+ (1,2) band contaminations were temporally limited to a moment around the aurora breakup. This is consistent with proceeding studies reporting that enhancements of N2+ (1,2) band were observed associated with International Brightness Coefficient 2-3 auroras. It is also suggested that the contaminations would be neglected in the polar cap and the sub-auroral zone, where strong aurora intensification are less observed. Further spectroscopic investigations at these wavelengths are needed especially for more precise evaluations of N2+ (1,2) band contaminations. For example, simultaneous 2-D imaging observation and spectroscopic measurement with high spectral resolutions for airglow in OH (3,1) band will make great advances in more robust temperature estimations in the auroral zone.

リンク情報
DOI
https://doi.org/10.1186/s40623-021-01360-0 本文へのリンクあり
共同研究・競争的資金等の研究課題
多波長近赤外分光・イメージング観測で解明する昼側オーロラ特性と地球大気の組成変動
共同研究・競争的資金等の研究課題
近赤外分光イメージングによる日照下オーロラ観測
共同研究・競争的資金等の研究課題
近赤外波長領域で開拓する地上オーロラ光学観測:昼側磁気圏可視化への挑戦
Scopus
https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85100067041&origin=inward 本文へのリンクあり
Scopus Citedby
https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85100067041&origin=inward
ID情報
  • DOI : 10.1186/s40623-021-01360-0
  • ISSN : 1343-8832
  • eISSN : 1880-5981
  • SCOPUS ID : 85100067041

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