Ionosphere / Electrons / Physics
Read the Source for the entire scientific paper.1. Introduction
Ionosphere is a shell of a large amount of electrons and it is disturbed by various causes such as volcanic eruptions [Heki, 2006;Dautermann et al., 2009], solar flares [Donnelly, 1976], earthquakes [ Cahyadi and Heki, 2015], and so on. Analyzing Total Electron Content (TEC) data is one of the most popular method to monitor the ionosphere. TEC data contains the number of electrons integrated along the line of sight between the GNSS satellites and the observation stations on the ground. Japan has a dense GNSS observation network (the GNSS earth observation network, GEONET) to collect daily TEC.