Ionospheric TEC disturbances over China during the intense magnetic storm of November, 2004

Ionospheric total electron content(TEC) disturbance characteristics are obtained during a strong geomagnetic storm in November 2004 based on the TEC data from 28 GPS observation stations in China. It is shown that the responses of the ionospheric TEC are mainly positive phase disturbances with the most intensity in the vicinity of latitude 35°N. It is found that the spatial correlation of TEC becomes stronger on disturbed days than on quiet days, and the correlative distance increases from 5 500 km on November 2nd to 8 000 on November 8th. During the main phase of the storm on the 8th, an accompanied TEC disturbance spread from northeast to southwest, with a meridian velocity about 120m/s, much higher than that of the zonal speed. Preliminary study has shown that the neutral wind, the dayside eastward penetrating electric field and the fountain effect may be the key factors to cause this positive disturbance with the most intensity in the vicinity of latitude 35°N. It is also revealed the complex coupling processes among the ionosphere, the solar wind and the magnetosphere, and also among the different latitude zones of the ionosphere.