TY - JOUR
T1 - 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
AU - Nishiyama, Takanori
AU - Taguchi, Makoto
AU - Suzuki, Hidehiko
AU - Dalin, Peter
AU - Ogawa, Yasunobu
AU - Brändström, Urban
AU - Sakanoi, Takeshi
N1 - Funding Information:
This work was supported by Japan Society for the Promotion of Science (JSPS), Grants-in-Aid for Young Scientists (A) 17H04857 and Scientific Research (B), Shimadzu Science Foundation, the prioritized project AJ0901 of Japanese Antarctic Research Expedition, and the Project Research KP301 of the National Institute of Polar Research. Magnetic field data and all-sky aurora image data at Syowa were provided by National Institute of Polar Research, Japan. The Upper Atmosphere Physics Monitoring Observation at Syowa Station was mainly supported by the Research Program of Japanese Antarctic Research Expedition (JARE) of the Ministry of Education, Culture, Sports, Science, and Technology of Japan (MEXT). All-sky imager at Kiruna data was provided by National Institute of Polar Research, Japan. The distribution of the magnetic field data has been partly supported by the IUGONET (Inter-university Upper atmosphere Global Observation NETwork) project ( http://www.iugonet.org/ ) funded by the MEXT. K-index data at Kiruna is produced by The Swedish Institute of Space Physics, Kiruna. We appreciate for making the K-index dataset available. All-sky camera data at Sodankylä is produced by Sodankylä Geophysical Observatory, University of Oulu. A timelapse movie is created by Dr. T. Raita, Sodankylä Geophysical Observatory, University of Oulu. We thank the NASA Goddard Earth Sciences (GES) Data and Information Services Center (DISC) ( https://disc.gsfc.nasa.gov/ ) for providing the Aura/MLS temperature and geopotential height dataset.
Funding Information:
The NIRAS was funded by Japan Society for the Promotion of Science (JSPS), Grants-in-Aid for Young Scientists (A) 17H04857 and Scientific Research (B) 20H01962. It was also partly funded by Shimadzu Science Foundation, the prioritized project AJ0901 of Japanese Antarctic Research Expedition, and the Project Research KP301 of the National Institute of Polar Research.
Funding Information:
This work was supported by Japan Society for the Promotion of Science (JSPS), Grants-in-Aid for Young Scientists (A) 17H04857 and Scientific Research (B), Shimadzu Science Foundation, the prioritized project AJ0901 of Japanese Antarctic Research Expedition, and the Project Research KP301 of the National Institute of Polar Research. Magnetic field data and all-sky aurora image data at Syowa were provided by National Institute of Polar Research, Japan. The Upper Atmosphere Physics Monitoring Observation at Syowa Station was mainly supported by the Research Program of Japanese Antarctic Research Expedition (JARE) of the Ministry of Education, Culture, Sports, Science, and Technology of Japan (MEXT). All-sky imager at Kiruna data was provided by National Institute of Polar Research, Japan. The distribution of the magnetic field data has been partly supported by the IUGONET (Inter-university Upper atmosphere Global Observation NETwork) project (http://www.iugonet.org/) funded by the MEXT. K -index data at Kiruna is produced by The Swedish Institute of Space Physics, Kiruna. We appreciate for making the K -index dataset available. All-sky camera data at Sodankylä is produced by Sodankylä Geophysical Observatory, University of Oulu. A timelapse movie is created by Dr. T. Raita, Sodankylä Geophysical Observatory, University of Oulu. We thank the NASA Goddard Earth Sciences (GES) Data and Information Services Center (DISC) (https://disc.gsfc.nasa.gov/) for providing the Aura/MLS temperature and geopotential height dataset.
Publisher Copyright:
© 2021, The Author(s).
PY - 2021/12
Y1 - 2021/12
N2 - 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 2 winter seasons, and 3 cases in which N2+ Meinel (1,2) band around 1.5μm was significant were identified. Focusing on two specific cases, detailed spectral characteristics with high temporal resolutions of 30 s 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 P 1(2) line (∼1523nm), N2+ emissions were almost equal to or greater than the OH line intensity. On the other hand, at a wavelength of P 1(4) line (∼1542nm), 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 P 1(2) and P 1(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 is 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.[Figure not available: see fulltext.].
AB - 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 2 winter seasons, and 3 cases in which N2+ Meinel (1,2) band around 1.5μm was significant were identified. Focusing on two specific cases, detailed spectral characteristics with high temporal resolutions of 30 s 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 P 1(2) line (∼1523nm), N2+ emissions were almost equal to or greater than the OH line intensity. On the other hand, at a wavelength of P 1(4) line (∼1542nm), 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 P 1(2) and P 1(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 is 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.[Figure not available: see fulltext.].
KW - Aurora
KW - Ground-based spectroscopic observations
KW - OH airglow
KW - OH rotational temperature
KW - Short wavelength infrared
KW - The Mesosphere and Lower Thermosphere
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U2 - 10.1186/s40623-021-01360-0
DO - 10.1186/s40623-021-01360-0
M3 - Article
AN - SCOPUS:85100067041
SN - 1343-8832
VL - 73
JO - Earth, Planets and Space
JF - Earth, Planets and Space
IS - 1
M1 - 30
ER -