In this study, we try to develop a space weather forecasting system by the coupled thermosphere-ionosphere model (TIE-GCM) and the GNSS observations through the data assimilation scheme (ensemble Kalman filter, EnKF). The GNSS observations can be (1) the radio occultation electron density profiles from the satellites of FORMOSAT-3/COSMIC or FORMOSAT-7/COSMIC-2, and (2) the total electron content (TEC) from the ground-based GNSS receiver networks. This space weather forecasting system can monitor the ionospheric states in a near real-time and give us the information of the effects of ionospheric variations on the GNSS positioning accuracy, especially during the ionospheric storm event.

Keywords: space weather, COSMIC-2, GNSS