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Abstract:
Conventionally, two-dimensional spatio-temporal variations and one-dimensional temporal variations such as GNSS-based TEC fluctuations and ionosonde data have been used for ionospheric disturbances. Ionospheric disturbances such as Pre-earthquake phenomena, and triggered by seismic ground motions, tsunamis, and typhoons, for which the physical mechanisms have not yet been elucidated, were also studied using GNSS-based TEC and Ionosonde data. In this study, we introduce the newly developed an ionospheric tomography system that is stable even during disturbances and can reconstruct the three-dimensional ionospheric electron density distribution. And we apply the developed tomography method to the GEONET data with typhoon signature and earthquake-related disturbances around Japan. Based on the obtained the three-dimensional structure, it is highly suggestive that ionospheric disturbances caused by typhoons were excited by atmospheric gravity waves, seismic fluctuations by sound waves, tsunami-induced fluctuations by atmospheric gravity waves, and earthquake precursors by electric fields. Details will be shown in the presentation.
