Ionospheric Earthquake Precursors and Space Weather Observed by FORMOSAT-7/COSMIC-2

Abstract:

FORMOSAT-7/COSMIC-2 (F7/C2), with the mission orbit of 550 km altitude, 24-deg inclination, and a period of 97 minutes, was launched on 25 June 2019. Tri-GNSS Radio occultation System (TGRS), Ion Velocity Meter (IVM), and RF beacon onboard F7/C2 six small satellites allow scientists to observe the plasma structure and dynamics in the mid-latitude, low-latitude, and equatorial ionosphere in detail. F7/C2 TGRS sounds ionospheric RO (radio occultation) electron density profiles, while F7/C2 IVM probes the ion density, ion temperature, and ion velocity at the satellite altitude. The electron density profiles, the ion density, ion temperature, and ion velocity, as well as the global ionospheric map (GIM) of the total electron content (TEC) derived from global ground-based GPS receivers are used to detect seismo-ionospheric precursors (SIPs) of the 14 November 2019 M7.1 Bitung, Indonesia Earthquake and to study space weather of ionospheric storms. The GIM TEC as well as F7/C2 RO NmF2 (F2-peak electron density) and HmF2 (F2-peak height) significantly increase specifically over the epicenter on 25-26 October 2019, which indicate SIPs of the M7.1 Bitung Earthquake being detected. Based on the dynamo theory, the IVM ion velocity is used to estimate the electric fields associated with the SIPs and ionospheric storms.