[P-CG19] 惑星大気圏・電磁圏

[PCG19-09] 2018 Global Dust Storm による火星大気圏-電離圏結合過程への影響の解明

*長田 章嗣¹、Liu Huixin¹、中川 広務²、Jain Sonal³、Rafkin Scot⁴、Hartwick Victoria⁴ (1.九州大学、2.東北大学、3.Laboratory for Atmospheric and Space Physics, University of Colorado Boulder、4.Southwest Research Institute, Boulder Office)

キーワード：火星大気、2018 グローバルダストストーム、大気潮汐、大気圏-電離圏結合 、MAVEN 衛星、NASA Ames Mars GCM

The atmosphere-Ionosphere coupling processes can strongly contribute to variabilities of the upper atmosphere on some planets, especially via atmospheric waves such as tides and gravity waves. Several previous studies have examined atmospheric tides on Mars. However, few studies have focused on tidal changes during 2018 global dust storms (GDS). To address this gap, we investigate 2018 GDS’s impacts on tides across lower, middle, upper atmosphere using the NASA Ames Mars Global Climate Model (MGCM) (0~90 km) and the MAVEN NGIMS observations (thermosphere, ionosphere). The analysis reveals significant changes in various tidal components. During calm-period, tides with wavenumber 1-4 all have prominent peak in equatorial region in the middle atmosphere. During GDS, these equatorial peaks diminish, while tidal amplitudes at high latitudes increase slightly for wave 1-4. We compare these changes with those seen by MAVEN to identify GDS impacts on Martian thermosphere and ionosphere via tidal propagation.