日本地球惑星科学連合2015年大会

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セッション記号 P (宇宙惑星科学) » P-EM 太陽地球系科学・宇宙電磁気学・宇宙環境

[P-EM06] Mesosphere-Thermosphere-Ionosphere Coupling in the Earth's Atmosphere

2015年5月27日(水) 11:00 〜 12:45 A01 (アパホテル&リゾート 東京ベイ幕張)

コンビーナ:*Huixin Liu(九州大学理学研究院地球惑星科学専攻 九州大学宙空環境研究センター)、大塚 雄一(名古屋大学太陽地球環境研究所)、Libo Liu(Institute of Geology and Geophysics, Chinese Academy of Sciences)、新堀 淳樹(京都大学生存圏研究所)、座長:新堀 淳樹(京都大学生存圏研究所)

11:45 〜 12:00

[PEM06-14] Longitudinal Variations of Low-Latitude Gravity Waves and Their Impacts on the Ionosphere

*Chihoko CULLENS1Scott ENGLAND1Thomas IMMEL1 (1.University of California Berkeley)

キーワード:Gravity Wave, Ionosphere, Tides

The lower atmospheric forcing has important roles in the ionospheric variability. Previous study suggested that atmospheric tides from the troposphere induce the wavenumber 4 signatures on the ionosphere. However, influences of lower atmospheric gravity waves on the ionospheric variability are still not clear due to the simplified gravity wave parameterizations in general circulation models (GCMs) and the limited knowledge of gravity wave distributions. In this study, we aim to study the longitudinal variations of gravity waves and their impacts on the ionospheric variability.
Variations of lower atmospheric gravity waves are characterized using SABER temperature observations from 2002 to 2012 and also the physically based gravity wave parameterization in the Specified-Dynamics Whole Atmosphere Community Climate Model (SD-WACCM). Longitudinal variations of gravity waves from SABER and WACCM show the largest variability in June-August at low latitudes. We have implemented these low-latitude gravity wave variations into the thermosphere-ionosphere-mesosphere-electrodynamics general circulation model (TIME-GCM) to study the responses of the ionosphere. TIME-GCM shows that wavenumber 3-4 components of TEC variations in June-August are increased by ~10-15% with the longitudinal variations of gravity waves but there are no significant changes in other months. Potential mechanisms of TEC responses to gravity wave variations will be discussed.