Development of a Prelude Satellite Equipped with Electric Field and Plasma Measurement Sensors Based on Statistical Evaluation of Seismic Precursors Using Artificial VLF Radio Waves Obtained from In-Orbit Observations

In this paper, we focus on the artificial VLF radio wave and show the result of the evaluation of the signal intensity decrease by the effect of ionospheric fluctuation, which is regarded as a sign phenomenon of earthquake occurrence. This paper also describes the mission design of Prelude (Precursor electric field observation CubeSat demonstrator) which is aiming at elucidation of the precursory mechanism of earthquake, and the development situation of hybrid sensor (electric field and plasma measurement) which is a mission instrument. We focused on the artificial VLF wave, in which the electromagnetic wave itself does not affect the ionosphere, and examined the relationship between the degree of electric field intensity decrease by the artificial VLF wave and the magnitude of the earthquake. And, by using lightning data of WWLLN (World Wide Lightning Location Network), the relation between change of generation number and energy and earthquake was evaluated. We have developed a CubeSat (6U Size) that is easy to mass-produce. However, the electric field measuring instrument and plasma measuring instrument mounted on the Demeter (130 kg large satellite) are each more than 1U in size. There are also no sensors for CubeSats that can be observed simultaneously. Therefore, we are working on the development of the hybrid sensor of 1U size or less which can measure electric field and plasma simultaneously on the orbit

Design and Development of Prelude, Satellite for Seismic Precedence Detection and Verification Using VLF Radio Waves for Navigation Obtained in Orbit

In this study, we analyzed the ionospheric anomaly in the D region, which precedes the occurrence of earthquakes, by focusing on the VLF radio wave for navigation, which is used for military communication, among the observation data of the earth observation satellite DEMETER (Detection of Electro-Magnetic Emissions Transmitted from Earthquake Regions). We analyzed the ionospheric anomaly in the D region that occurs prior to an earthquake. Next, based on the results, we propose the design of a 6U nano-satellite dedicated to the detection of earthquake precursory phenomena using navigational VLF radio waves: Prelude (Precursory electric field observation CubeSat demonstrator). The design of Prelude (Precursory electric field observation CubeSat demonstrator) is proposed. In a previous study, the authors of Němec, Kamogawa et al. attributed this decrease in intensity to an increase in electron density in the D region. Kamogawa et al. attributed this decrease to an increase in electron density in the D region. Based on these results, our proposed satellite mission will be to observe ionospheric anomalies in the D-region that precede earthquakes for the purpose of short-term earthquake prediction in the future. Němec et al. and Kamogawa et al. have studied the variation of electron density in the D region by analyzing the radio waves generated by lightning. However, the accuracy of this method is limited for the following three reasons: 1) the frequency of lightning is different depending on the season, 2) the frequency range of lightning is wider than that of thunderstorms, and 3) there are dispersion characteristics of radio waves due to ionospheric plasma. Therefore, in this study, we focused on the variation of electron density in the D region by focusing on the VLF charged wave for navigation, which has a constant frequency, continuous transmission, and temporal and spatial continuity. As a case study analysis, we confirmed the validity of the analysis of navigational VLF waves by focusing on the earthquake in southern Sumatra. The results show that the navigational VLF signal intensity decreases significantly before the earthquake compared to the trajectories in the comparison counties. This suggests that the effects of ionospheric fluctuations shown by Němec In addition, we found that the VLF radio wave strength of Prelude was significantly reduced before the earthquake. Furthermore, this study showed the effectiveness of navigational VLF radio waves as a new analysis target for Prelude\u27s mission analysis. Therefore, we considered that there is a room to introduce a flexible system for the design and development of the science mission during the design and development of this satellite by using Systems Modeling

Robust uncertainty quantification of the volume of tsunami ionospheric holes for the 2011 Tohoku-Oki earthquake: towards low-cost satellite-based tsunami warning systems

We develop a new method to analyze the total electron content (TEC) depression in the ionosphere after a tsunami occurrence. We employ Gaussian process regression to accurately estimate the TEC disturbance every 30 s using satellite observations from the global navigation satellite system (GNSS) network, even over regions without measurements. We face multiple challenges. First, the impact of the acoustic wave generated by a tsunami onto TEC levels is nonlinear and anisotropic. Second, observation points are moving. Third, the measured data are not uniformly distributed in the targeting range. Nevertheless, our method always computes the electron density depression volumes, along with estimated uncertainties, when applied to the 2011 Tohoku-Oki earthquake, even with random selections of only 5 % of the 1000 GPS Earth Observation Network System receivers considered here over Japan. Also, the statistically estimated TEC depression area mostly overlaps the range of the initial tsunami, which indicates that our method can potentially be used to estimate the initial tsunami. The method can warn of a tsunami event within 15 min of the earthquake, at high levels of confidence, even with a sparse receiver network. Hence, it is potentially applicable worldwide using the existing GNSS network

グローバルサーキットと福島原発事故

第3回極域科学シンポジウム/第36回極域宙空圏シンポジウム 11月26日（月）、27日（火） 国立極地研究所 2階ラウン

Revisiting study of a diurnal variation of atmospheric electric field - Carnegie Curve - observed at Syowa Station

第6回極域科学シンポジウム[OS] 宙空圏11月16日（月）　国立極地研究所１階交流アトリウ

地吹雪時の吹雪粒子の帯電と大気電場変動の関係

第6回極域科学シンポジウム[OS] 宙空圏11月16日（月）　国立極地研究所 2階 大会議

Current status of Iceland-Syowa conjugate observation in 2019

The Tenth Symposium on Polar Science/Ordinary sessions: [OS] Space and upper atmospheric sciences, Wed. 4 Dec. / Institute of Statistics and Mathematics (ISM) Seminar room 2 (D304) (3rd floor

Jishin ni kanrensuru taiki denji hakko gensho no kenkyu

制度:新 ; 文部省報告番号:甲1427号 ; 学位の種類:博士(理学) ; 授与年月日:2000-03-15 ; 早大学位記番号:新2945 ; 理工学図書館請求番号:2456早稲田大