Research on climate change based on the derivation of the longest ionospheric density trends

• Project/Area Number: 20KK0313
• Research Category: Fund for the Promotion of Joint International Research (Fostering Joint International Research (A))
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 17010:Space and planetary sciences-related
• Research Institution: National Institute of Polar Research
• Principal Investigator: Ogawa Yasunobu 国立極地研究所, 先端研究推進系, 教授 (00362210)
• Project Period (FY): 2021 – 2024
• Project Status: Completed (Fiscal Year 2024)
• Budget Amount: ¥13,650,000 (Direct Cost: ¥10,500,000、Indirect Cost: ¥3,150,000)
• Keywords: 気候変動 / 寒冷化 / 温暖化 / 超高層大気 / 極域 / 電離圏 / 地球温暖化

Outline of Research at the Start

本研究では、「地球規模で温暖化が生じている1980年代以降」と、「北極圏のみ温暖化が起きていた20世紀前半」の2つの期間に着目して、北極圏の超高層大気の長期変動及び寒冷化トレンドにおける両者の相違点を解明することを目的とする。そのために、超高層大気の質量密度の新たな計測手法の検証及び精度向上と、北極域電離圏の観測初期（1945年以前）の紙媒体データを含む約86年間の統一データベースの整備を、UiT ノルウェー北極大学にて国際共同で実施する。それにより、約86年間の世界最長となる北極域電離圏電子密度分布の長期変動・トレンドを精度よく導出し、地球温暖化を含む気候変動のプロセス理解に貢献する。

Outline of Final Research Achievements

We have studied long-term ionospheric variations using data from the Tromsoe ionosonde since 1932. To investigate Arctic ionospheric variations in relation to the Arctic warming and cooling before the 1970s, we have developed a Tromsoe ionosonde database that makes it possible to study the daily variations over about 90 years. During the 1940s to 1960s, when the Arctic surface was cooling, a gradually increasing trend in the critical frequency of the F2 layer, foF2, was observed in the Tromsoe ionosonde data with a rate of 0.022 MHz/year. This can be explained by the Earth's atmosphere global energy balance. As for the trend of foF2 since 2001, there is a clear decrease with a rate of -0.046 MHz/year. These trends are qualitatively consistent with the changes in the upper atmosphere that can be inferred from the cooling and warming of the Arctic surface.

Academic Significance and Societal Importance of the Research Achievements

超高層大気の長期変動の研究は、気候変動研究として発展してきているが、そのほとんどの研究は1980年代以降に観測を開始したデータを用いており、1980年代以降の地球温暖化に焦点が置かれてきた。それに対し、本研究では「20世紀前半」と「1980年代以降」の異なる北極圏温暖化の特徴に着目して、超高層大気の長期変動の特徴を明らかにすることに成功した。この研究成果により、国内外で先行して実施されている大気大循環モデル（GCM）数値計算結果との直接的な比較研究が初めて実施可能となり、20世紀前半から現在に至る超高層大気の長期変動について、体系化された学術的見解を得ることに貢献する。

Research Products

• [Int'l Joint Research] UiTノルウェー北極大学(ノルウェー) (2025)
  • Year and Date: 2025-01-02
• [Int'l Joint Research] UiTノルウェー北極大学(ノルウェー) (2022)
• [Journal Article] Joule Heating rate at high-latitudes by Swarm and ground-based observations compared to MHD simulations (2024)
  • Author(s): Kauristie Kirsti、Marghitu Octav、van de Kamp Max、Hoppe Theresa、Honkonen Ilja、Blagau Adrian、Ivan Ionut Madalin、Codrescu Mihail、Ridley Aaron、Toth Gabor、Ogawa Yasunobu、Trenchi Lorenzo
  • Journal Title: Journal of Atmospheric and Solar-Terrestrial Physics Volume: 260 Pages: 106254-106254
  • DOI: 10.1016/j.jastp.2024.106254
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Influence of meteoric smoke particles on the incoherent scatter measured with EISCAT VHF (2024)
  • Author(s): Gunnarsdottir Tinna L.、Mann Ingrid、Feng Wuhu、Huyghebaert Devin R.、Haeggstroem Ingemar、Ogawa Yasunobu、Saito Norihito、Nozawa Satonori、Kawahara Takuya D.
  • Journal Title: Annales Geophysicae Volume: 42 Issue: 1 Pages: 213-228
  • DOI: 10.5194/angeo-42-213-2024
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Response Time of Joule Heating Rate and Nitric Oxide Cooling Emission During Geomagnetic Storms: Correlated Ground‐Based and Satellite Observations (2024)
  • Author(s): Bag Tikemani、Ogawa Yasunobu
  • Journal Title: Journal of Geophysical Research: Space Physics Volume: 129 Issue: 2
  • DOI: 10.1029/2023ja032072
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Effect of the mirror force on the collision rate due to energetic electron precipitation: Monte Carlo simulations (2023)
  • Author(s): Katoh Yuto、Rosendahl Paul Simon、Ogawa Yasunobu、Hiraki Yasutaka、Tadokoro Hiroyasu
  • Journal Title: Earth, Planets and Space Volume: 75 Issue: 1 Pages: 117-117
  • DOI: 10.1186/s40623-023-01871-y
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Interhemispheric Coupling Study by Observations and Modelling (ICSOM): Concept, Campaigns, and Initial Results (2023)
  • Author(s): Sato, K., Y. Tomikawa, M. Kohma, R. Yasui, D. Koshin, H. Okui, S. Watanabe, K. Miyazaki, M. Tsutsumi, D. Murphy, C. Meek, Y. Tian, M. Ern, G. Baumgarten, J. L. Chau, X. Chu, R. Collins, P. J. Espy, H. Hashiguchi, A. J. Kavanagh, R. Latteck, F. Lubken, M. Milla, S. Nozawa, Y. Ogawa et al.
  • Journal Title: Journal of Geophysical Research: Atmospheres Volume: 128 Issue: 11
  • DOI: 10.1029/2022jd038249
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Types of pulsating aurora: comparison of model and EISCAT electron density observations (2022)
  • Author(s): Tesema Fasil、Partamies Noora、Whiter Daniel K.、Ogawa Yasunobu
  • Journal Title: Annales Geophysicae Volume: 40 Issue: 1 Pages: 1-10
  • DOI: 10.5194/angeo-40-1-2022
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Two Techniques for Determining F‐Region Ion Velocities at Meso‐Scales: Differences and Impacts on Joule Heating (2022)
  • Author(s): Kavanagh Andrew J.、Ogawa Yasunobu、Woodfield Emma E.
  • Journal Title: Journal of Geophysical Research: Space Physics Volume: 127 Issue: 6
  • DOI: 10.1029/2021ja030062
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Precipitating Electron Energy Spectra and Auroral Power Estimation by Incoherent Scatter Radar With High Temporal Resolution (2022)
  • Author(s): Tesfaw Habtamu W.、Virtanen Ilkka I.、Aikio Anita T.、Nel Amore、Kosch Michael、Ogawa Yasunobu
  • Journal Title: Journal of Geophysical Research: Space Physics Volume: 127 Issue: 4
  • DOI: 10.1029/2021ja029880
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Low-altitude ion upflow observed by EISCAT and its effects on supply of molecular ions in the ring current detected by Arase (ERG) (2021)
  • Author(s): Takada, M., Seki, K., Ogawa, Y., Keika, K., Kasahara, S., Yokota, S., et al.
  • Journal Title: Journal of Geophysical Research: Space Physics Volume: 126 Issue: 5
  • DOI: 10.1029/2020ja028951
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Ionospheric Electron Density and Conductance Changes in the Auroral Zone During Substorms (2021)
  • Author(s): Stepanov N. A.、Sergeev V. A.、Shukhtina M. A.、Ogawa Y.、Chu X.、Rogov D. D.
  • Journal Title: Journal of Geophysical Research: Space Physics Volume: 126 Issue: 7
  • DOI: 10.1029/2021ja029572
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Presentation] Study of long-term ionospheric variations based on Tromsoe Ionosonde and EISCAT radar data (2024)
  • Author(s): Y. Ogawa, M. G. Johnsen, N. Gulbrandsen, A. D. Lokke, I. Mann, and I. Haggstrom
  • Organizer: The 21st International EISCAT Symposium 2024 and the 48th Annual European Meeting on Atmospheric Studies by Optical Methods
  • Int'l Joint Research
• [Presentation] Study of long-term ionospheric variations based on Tromsoe Ionosonde and EISCAT radar data (2024)
  • Author(s): Y. Ogawa, M. G. Johnsen, N. Gulbrandsen, A. D. Lokke, I. Mann, and I. Haggstrom
  • Organizer: The 15th Symposium on Polar Science
• [Presentation] Joint Japanese-Norwegian observations with EISCAT and ground-based instruments (2023)
  • Author(s): Yasunobu Ogawa
  • Organizer: Blix/Andoya Space Center-ISAS/JAXA and NIPR meeting
• [Presentation] Japan's Activities for the EISCAT_3D Project (2023)
  • Author(s): Yasunobu Ogawa, Hiroshi Miyaoka, Satonori Nozawa, Taishi Hashimoto, Shin-ichiro Oyama, Koji Nishimura, Takuo T. Tsuda, Hitoshi Fujiwara, Masaki Tsutsumi, Yoshimasa Tanaka, Takanori Nishiyama, Mizuki Fukizawa, Yoshizumi Miyoshi, Keisuke Hosokawa, Takuji Nakamura, Ryoichi Fujii
  • Organizer: JpGU2023 meeting
• [Presentation] EISCAT_3D and Japan's Activities (2023)
  • Author(s): Yasunobu Ogawa, Hiroshi Miyaoka, Satonori Nozawa, Taishi Hashimoto, Shin-ichiro Oyama, Koji Nishimura, Takuo T. Tsuda, Hitoshi Fujiwara, Masaki Tsutsumi, Yoshimasa Tanaka, Takanori Nishiyama, Mizuki Fukizawa, Yoshizumi Miyoshi, Keisuke Hosokawa, Takuji Nakamura, Ryoichi Fujii
  • Organizer: The 14th Symposium on Polar Science
• [Presentation] Statistical study of high energy electron precipitation based on Arase satellite - EISCAT collaborative observation data (2023)
  • Author(s): Y. Ogawa, M. Fukizawa, Y. Miyoshi, K. Hosokawa, S. Oyama, K. Shiokawa, K. Seki, S. Kurita, K. Asamura, S. Kasahara, T. Mitani, S. Matsuda, Y. Kasahara, Y. Kato, I. Shinohara, and ERG-EISCAT project team
  • Organizer: ISAR-7
  • Int'l Joint Research
• [Presentation] Simulation study of the effect of the mirror force on the collision rate due to energetic electron precipitation (2022)
  • Author(s): Katoh, Y., P. S. Rosendahl, Y. Ogawa, Y. Hiraki, and H. Tadokoro
  • Organizer: URSI-JRSM 2022
  • Int'l Joint Research
• [Presentation] Japan's Activities for the EISCAT_3D Project (2022)
  • Author(s): Y. Ogawa, H. Miyaoka, S. Nozawa, T. Hashimoto, S. Oyama, K. Nishimura, T. T. Tsuda, H. Fujiwara, M. Tsutsumi, Y. Tanaka, T. Nishiyama, T. Nakamura, R. Fujii, C. Heinselm
  • Organizer: JpGU2022 meeting
  • Int'l Joint Research
• [Presentation] Possible common program (CP) modes for EISCAT_3D (2022)
  • Author(s): Y. Ogawa, and EISCAT_3D CP Working Group members
  • Organizer: 20th EISCAT International symposium
  • Int'l Joint Research / Invited
• [Presentation] EISCAT_3D and Japan’s Activities (2022)
  • Author(s): Y. Ogawa, H. Miyaoka, S. Nozawa, T. Hashimoto, S. Oyama, K. Nishimura, T. T. Tsuda, H. Fujiwara, M. Tsutsumi, Y. Tanaka, T. Nishiyama, M. Fukizawa, T. Nakamura, R. Fujii, C. Heinselm
  • Organizer: 第152回地球電磁気・地球惑星圏学会講演会
  • Invited
• [Presentation] Study on Atmospheric Escape (2021)
  • Author(s): Y. Ogawa
  • Organizer: The 2nd NIPR-UiT Online Monthly Joint Seminar
• [Presentation] An idea for possible common program (CP) modes for EISCAT_3D (2021)
  • Author(s): Y. Ogawa
  • Organizer: 14th EISCAT_3D user meeting 及び 2nd EISCAT_3D Software and Data meeting