Global Total Electron Content Variations during the Major Magnetic Storm in Nov. 2004

We estimated the global total electron content (TEC) variations during the major magnetic storm in Nov. 2004 using TEC data provided by IGS. It was found that before this strong magnetic storm, the maximum of quiet-time day-to-day absolute TEC variations (dI) occurred usually at equatorial belt and mainly in the 8-19 LT sector. The quiet-time day-to-day relative TEC variations (dI/I) ranged from -60% to 130%. The maximum of dI/I in quiet period occurred mainly at equatorial belt and high-latitude belts, and was observed usually in the night or early morning sector. After the sudden commencement of this magnetic storm, positive phase storm (dI/I > 0) took place firstly at high-latitude belt, and then propagated equatorward. Positive phase storm dominated at both the northern and southern hemisphere during the main phase of this magnetic storm, while negative phase storm (dI/I < 0) occurred mainly at the southern hemisphere during the recovery phase.