[P-EM10] Space Weather and Space Climate

[PEM10-P10] Plasmaspheric Electron Content Contribution to Total Electron Content: Insights from Ground-Based and FORMOSAT-3/COSMIC Radio Occultation Data

*Chun-Yen Huang¹、Jann-Yenq G Liu²、CHIYEN LIN²、Tatsuhiro Yokoyama¹ (1.Research Institute for sustainable humanosphere, Kyoto University、2.National Central University, Taiwan)

キーワード：Plasmasphere, ionosphere, total electron content

This long-term study examines the contribution of plasmaspheric electron content (PEC) to total electron content (TEC) using data from FORMOSAT-3/COSMIC, CODEGIM, and ground-based GPS receiver-derived TEC from 2006 to 2017. The analysis focuses on TEC measurements obtained from zenith-pointing antennas used for the satellite’s precise orbit determination (POD). The PEC maps derived from POD TEC are constructed using a 15th-order spherical harmonic expansion, with a temporal resolution of 2 hours and spatial resolutions of 2.5° in latitude and 5° in longitude, and are subsequently compared with CODEGIM TEC. Additionally, ground-based GPS receiver-derived TEC, with lines of sight nearly parallel to those of PODTEC, is used for detailed comparison and to analyze the proportion of electron content above 800 km. The results reveal that PEC makes a significant contribution to TEC, exhibiting distinct temporal and spatial variations. In terms of diurnal variation, PEC contribution depends on magnetic latitude, reaching a minimum (~20%) during the day and a maximum (~60%) at night. Regarding seasonal variation, PEC influence is stronger during the June and December solstices compared to the equinoxes. From a spatial perspective, PEC contributions are most pronounced within ±15° magnetic latitudes. These findings provide valuable insights into the temporal and spatial characteristics of PEC, improving our understanding of its role in ionospheric dynamics.