A statistic analysis of ionospheric responses to the severe magnetic storms in Taiwan Sector

This study presents the results of a temporal statistic study of the ionospheric response to the magnetic storm disturbances. The study is based on the F layer critical frequency (foF2) and the minimum virtual height (h¡¦F) from Chung-Li, which is on the equatorial anomaly station. In this paper we examined a pre- 15 day running median of the foF2 and h¡¦F as a reference for identifying abnormal signals during all of 35 Kp¡U 6 magnetic storms from 1994 to1999. Results show the negative ionospheric storm phase over equatorial anomaly area, observed in summer and winter and the positive phase in equinox. We also present results of a storm time and general temporal variation associated with the foF2 disturbances. Meanwhile, this study confirms earlier studies that show the seasonal and Local Time effects dependent foF2. Although, the negative ionospheric storm phase over equatorial anomaly area is intensified with the disturbance zonal electric field and the meridional wind.