Equinoctial Asymmetry of the Ionosphere and Thermosphere

2014 Fiscal Year Final Research Report

• Project/Area Number: 23540523
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Space and upper atmospheric physics
• Research Institution: Nagoya University
• Principal Investigator: OTSUKA Yuichi 名古屋大学, 太陽地球環境研究所, 准教授 (40314025)
• Co-Investigator(Kenkyū-buntansha): YAMAMOTO Mamoru 京都大学, 生存圏研究所, 教授 (20210560)
• Project Period (FY): 2011-04-28 – 2015-03-31
• Keywords: 電離圏 / 熱圏 / 中間圏 / 乱流 / レーダー / 春秋非対称

Outline of Final Research Achievements

Eddy diffusion coefficients have been estimated from long-term measurements of the mesospheric echo observed with the MU radar, which is a large atmospheric radar. We have found that the eddy diffusion coefficients are higher in Sep. equinox than Mar. equinox. According to the results obtained from the global simulation, this equinoctial asymmetry of the mesospheric eddy diffusion coefficients is responsible for that of the ionospheric plasma density. We have analyzed thermospheric neutral wind data obtained by Fabry Perot interferometer at Chiang Mai, Thailand, and show that equinoctial asymmetry of the meridional thermospheric winds is responsible for that of plasma bubble occurrence rate.

Free Research Field

超高層大気物理学