日本地球惑星科学連合2019年大会

講演情報

[E] ポスター発表

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-EM09] Vertical coupling in the atmosphere and Ionosphere

2019年5月29日(水) 10:45 〜 12:15 ポスター会場 (幕張メッセ国際展示場 8ホール)

コンビーナ:Liu Huixin(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)、Chang Loren(Institute of Space Science, National Central University)、大塚 雄一(名古屋大学宇宙地球環境研究所)

[PEM09-P14] The statistical study of the growth rates of Medium-Scale Traveling Ionospheric Disturbances observed with GPS-TEC

*池田 孝文1齊藤 昭則1津川 卓也2品川 裕之2 (1.京都大学大学院理学研究科地球物理学教室、2.情報通信研究機構)

キーワード:中規模伝搬性電離圏擾乱、GPS-TEC、電離層

We think two mechanism, E-F coupling and Perkins Instability, will relate to growth for nighttime-MSTID in mid-latitude [Tsunoda and Cosgrove., 2001 ; Perkins., 1973]. Linear growth rate of perturbation intensity of Pedersen conductivity expected from E-F coupling is around 15 minutes [Yokoyama et al., 2009], which is far shorter than one expected from Perkins Instability [Fukao and Kelley, 1991 ; Miller et al., 1997 ; Shiokawa et al., 2003]. However, Es layer’s spatial and temporal scale is less than 100km and 15min [Maeda et al., 2013 ; S.Saito et al., 2007]. They are different from MSTID’s ones, which are 200-400 km and around 2hours [Otsuka et al., 2011]. To decide which instability is responsible for growth of nighttime MSTID, the growth rate of MSTID was observationally determined with ground-based GPS network data.

We statistically investigated the growth rate of nighttime-MSTID in Japan in 2014 observed with GPS-TEC. The growth rate of nighttime -MSTID observed was 1.0 - 6.0 × 10-4 s-1 during 1800LT-2400LT in summer.Linear growth rate of Perkins instability in summer was 1.0 - 6.0 × 10-4 s-1 during 1800LT - 2400LT, so they were less than one of the E-F coupling instability. Also,Seasonal distribution of observed growth rate before midnight was similar to that of linear growth rate.U×B derived by GAIA model was high in spring - summer and seasonal distribution of U×B was similar to that of linear growth rate. Therefore, the growth of MSTID when propagating is not determined by E-F coupling instability but Perkins instability and neutral wind.