Upper Atmosphere Cooling Investigated by Precipitating Particles

• Project/Area Number: 20K04052
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 17010:Space and planetary sciences-related
• Research Institution: National Institute of Polar Research
• Principal Investigator: Yasunobu Ogawa 国立極地研究所, 共同研究推進系, 教授 (00362210)
• Co-Investigator(Kenkyū-buntansha): 加藤 雄人 東北大学, 理学研究科, 教授 (60378982)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Project Status: Completed (Fiscal Year 2022)
• Budget Amount: ¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000); Fiscal Year 2022: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000); Fiscal Year 2021: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000); Fiscal Year 2020: ¥2,340,000 (Direct Cost: ¥1,800,000、Indirect Cost: ¥540,000)
• Keywords: 超高層大気 / 降下粒子 / 電離圏 / 寒冷化

Outline of Research at the Start

本研究では、宇宙空間・磁気圏から地球に降り込む電子の影響を活用した超高層大気の質量密度の新たな計測手法を確立することにより、超高層大気の寒冷化や沈降などの長期的変化の描像を明らかにすることが目的である。まず、高度 80～150 km の大気質量密度を推定する手法開発を行い、次にその手法をDMSP衛星及び欧州非干渉散乱（EISCAT）レーダーの両データに適用することで、約40年間にわたる大気質量密度の長期トレンドを導出する。

Outline of Final Research Achievements

In order to quantitatively understand various long-term variations in the polar upper atmosphere, we conducted (1) a detailed investigation of upper atmosphere ionization associated with electron precipitation to the earth and (2) investigations of long-term variations in polar ionospheric ion temperature based on European Incoherent Scatter (EISCAT) radar data.
Numerical simulation results show that (1) the maximum collision rate in the altitude range lower than 100 km becomes one order of the magnitude smaller depending on the effect of the mirror force on the electron precipitation. As for (2), the characteristics of ionospheric cooling can be estimated with higher accuracy using 43 years of EISCAT radar data, and differences in the characteristics of ionospheric cooling/warming depending on the season and altitude are also clarified.

Academic Significance and Societal Importance of the Research Achievements

（１）の研究成果については、波動粒子相互作用によるピッチ角散乱に起因する高エネルギー電子の降下による電離圏応答の精密なモデル化において、ミラーフォースの重要性を示唆するものである。（２）の研究成果については、下層大気から熱圏までを包括する全大気圏における気候変動の理解と将来予測に貢献する内容である。

Research Products

• [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] 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
• [Journal Article] Fine Structure of Chorus Wave Packets: Comparison Between Observations and Wave Generation Models (2021)
  • Author(s): Zhang X.‐J.、Demekhov A. G.、Katoh Y.、Nunn D.、Tao X.、Mourenas D.、Omura Y.、Artemyev A. V.、Angelopoulos V.
  • Journal Title: Journal of Geophysical Research: Space Physics Volume: 126 Issue: 8 Pages: 1-17
  • DOI: 10.1029/2021ja029330
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Electron Density Depletion Region Observed in the Polar Cap Ionosphere (2021)
  • Author(s): Bjoland L. M.、Ogawa Y.、Lovhaug U. P.、Lorentzen D. A.、Hatch S. M.、Oksavik K.
  • Journal Title: Journal of Geophysical Research: Space Physics Volume: 126 Issue: 1
  • DOI: 10.1029/2020ja028432
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Optical calibration system of NIPR for aurora and airglow observations (2020)
  • Author(s): Ogawa Y.、Kadokura A.、Ejiri M.K.
  • Journal Title: Polar Science Volume: 26 Pages: 100570-100570
  • DOI: 10.1016/j.polar.2020.100570
  • Peer Reviewed
• [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] Evaluation of nonlinear effects in the pitch angle scattering process of energetic electrons into the loss cone by coherent whistler-mode waves (2021)
  • Author(s): Ishizawa, G., Y. Katoh, M. Kitahara
  • Organizer: URSI GASS 2021
  • Int'l Joint Research
• [Presentation] 磁気赤道周辺での kinetic Alfven wave による電子加速過程に関するテスト粒子計算 (2021)
  • Author(s): 齋藤幸碩, 加藤雄人, 北原理弘, 川面洋平, 木村智樹, 熊本篤志
  • Organizer: 第150回 地球電磁気・地球惑星圏学会 総会および講演会
• [Presentation] Characteristics of CME- and CIR-driven ion upflows in the polar ionosphere (2021)
  • Author(s): Ogawa Y., K. Seki, K. Keika, and Y. Ebihara
  • Organizer: 43rd COSPAR Scientific Assembly
  • Int'l Joint Research / Invited
• [Presentation] Current EISCAT and next EISCAT_3D database (2020)
  • Author(s): 小川 泰信, 野澤 悟徳, 田中 良昌, 橋本 大志, 大山 伸一郎, 津田 卓雄, 藤原 均, 西村 耕司, 宮岡 宏, 中村 卓司, 藤井 良一, Ingemar Haggstrom, Craig Heinselman
  • Organizer: 第148回 地球電磁気・地球惑星圏学会 総会および講演会
• [Presentation] Simulation study of the energetic electron precipitation in the polar region considering the magnetic mirror force (2020)
  • Author(s): 加藤雄人, パウル ローゼンダール, 小川泰信
  • Organizer: 第148回 地球電磁気・地球惑星圏学会 総会および講演会
• [Presentation] オーロラ電子加速過程に関わる電磁圏プラズマの沿磁力線分布についての研究 (2020)
  • Author(s): 齋藤幸碩, 加藤雄人, 熊本篤志, 木村智樹, 川面洋平
  • Organizer: 第148回 地球電磁気・地球惑星圏学会 総会および講演会
• [Presentation] Plasma distribution solver for the field-aligned distribution of ionospheric/magnetospheric plasma related to the auroral electron acceleration process (2020)
  • Author(s): Saito, K., Y. Katoh, A. Kumamoto, T. Kimura, Y. Kawazura
  • Organizer: AGU Fall Meeting 2020
  • Int'l Joint Research