[P-EM13] Coupling Processes in the Atmosphere-Ionosphere System

[PEM13-25] Ionospheric responses on the 21 August 2017 solar eclipse by using three-dimensional GNSS tomography

*陳 佳宏¹、Lin Charles¹、劉 正彦^2,3,4、齊藤 昭則⁵ (1.台湾国立成功大学地球科学学科、2.台湾国立中央大学宇宙科学とテクノロジー研究センター、3.台湾国立中央大学宇宙科学とエンジニアリング学科、4.台湾国立中央大学宇宙とリモートセンシング研究センター、5.日本京都大学理学院研究科地球惑星科学専攻)

キーワード：日食、3D トモグラフィー、全球測位衛星システム、電離層プラズマ密度低下

The change of ionospheric plasma density is strongly affected by the solar activity, such as solar flare. The solar eclipse is one kinds of solar activity may cause the temporal plasma variances in the ionosphere when the moon shadow pass by. In this study, we study the 3D ionospheric plasma density stucture by using a 3D tomography algorithm with the dense GNSS networks around the Northern America during the August 2017 solar eclipse event. Results show that the most ionospheric plasma density depletion is around 40% compared with the previous day of solar eclipse, and this density depletion is distributed to all the altitudes. A Fourier analyses is further conducted to derive the vertical phase and group velocities of the ionospheric plasma propagations and try to find the disturbance source of the ionospheric plasma density during the solar eclipse.