Japan Geoscience Union Meeting 2025

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[E] Oral

P (Space and Planetary Sciences ) » P-EM Solar-Terrestrial Sciences, Space Electromagnetism & Space Environment

[P-EM12] Coupling Processes in the Atmosphere-Ionosphere System

Mon. May 26, 2025 3:30 PM - 5:00 PM 303 (International Conference Hall, Makuhari Messe)

convener:Keisuke Hosokawa(Department of Communication Engineering and Informatics, University of Electro-Communications), Huixin Liu(Earth and Planetary Science Division, Kyushu University SERC, Kyushu University), Yuichi Otsuka(Institute for Space-Earth Environmental Research, Nagoya University), Loren Chang(Department of Space Science and Engineering, National Central University), Chairperson:Takanori Nishiyama(National Institute of Polar Research), Yang-Yi Sun(China University of Geosciences)


4:00 PM - 4:15 PM

[PEM12-39] Intraseasonal Variability of the Equatorial Ionosphere Responses to the Madden-Julian Oscillation

*Xu Zhou1, Guiwan Chen2, Xinan Yue1, Ruilong Zhang1, Akimasa Yoshikawa3 (1.Institute of Geology and Geophysics, Chinese Academy of Sciences, 2.Institute of Atmospheric Physics, Chinese Academy of Sciences, 3.Department of Earth and Planetary Sciences, Kyushu University)

Keywords:Equatorial Ionosphere, Plasma Drifts, Madden-Jullian Oscillation, Whole Atmosphere Simulation, Atmospheric Tides

This study investigates the response of the equatorial ionosphere to the tropospheric Madden-Jullian Oscillation (MJO) using the Whole Atmosphere Community Climate Model-eXtended (WACCM-X). The main results indicate that the intraseasonal variability of ionospheric vertical plasma drifts (Viz) is generally strong around boreal winters and exhibits significant eastward-propagating signals. Composite analysis showed that, during the December-January-February-March (DJFM) season, Viz was generally negative when the MJO was active over the Maritime Continent (phase 5) and positive when the MJO was active over the Indian Ocean (phase 2). The magnitude of MJO impact on Viz achieves ~1.2 m/s, representing roughly 10% of the seasonal mean. The eastward-propagating wavenumber-4 is apparently strong during MJO phases 5 and 1–2, which is examined to be associated with non-migrating tides below. Term analysis revealed the importance of zonal winds in driving the Viz responses. This study emphasizes the importance of tropospheric sources that affect the geospace environment.