Analysis of the Intense Magneticstorm of July, 2000 and of October, 2003 Using the Technique for Nowcasting of GPS TEC Data

With a worldwide GPS network, the data of the July 14-18, 2000 geomagnetic storm and the October 28-November 1, 2003 storm is studied and compared using the technique for nowcasting of GPS TEC developed by the ionospheric station of Wuhan ionosphere observatory. In this paper, the ionospheric responses and the TEC variation during these two storms are discussed, especially the reducing and moving of the perturbation structure around the geomagnetic equator during storms and the ionospheric responses of high latitude part are analyzed. The results show that the ionospheric responses during these two storms are different and this difference is primarily caused by the seasonal difference of the magnetospheric energy deposition into the polar upper atmosphere. It is shown that the TEC variation is associated with the local time the solar perturbing occurred and the coupling of the ionospheric particles of high latitude with the solar particle. If there are several magnetic storms occurring in series, the ionospheric responses are more complex and disordered than the state that only one storm occur in a few days.