Effects of a major storm on GPS amplitude scintillations and phase fluctuations at Wuhan in China

GPS scintillation and TEC measurements have been carried out at Wuhan (114.36°E, 30.53°N, magnetic latitude 19.4°) since 2003. In this paper effects of a major storm on GPS amplitude scintillations and phase fluctuations are investigated. Remarkably enhanced activity and intensity of amplitude scintillations during the latter main phase of the storm, in the night of November 10, 2004, were observed in the region of the ionospheric equatorial anomaly in the southern China. TEC depletions and its rapid fluctuations occurred at the same time when enhanced scintillations occurred. The statistic analysis shows there is a remarkable positive correlation between the ROTI index and the S4 index. The irregularity apparent drift velocity at the storm time is estimated using data of the rate of TEC changes collected at three spaced stations. It is obtained that the irregularity drifts westward along the zonal direction with the velocity changing from about 130 m/s to 40 m/s in the night of November 10, 2004.