Using IGS Data to Analyze the Long-Term Variations of Total Electron Content

This paper analyzes the regional ionosphere total electron content (TEC) long-term variations obtained via using GPS measurements. For this purpose, the authors used the TEC data from TEC maps (global maps in IONEX format) over 11 years. TEC at five IGS tracking stations of China was interpolated by a suitable method. Results show that the peak of TEC for different stations approximately occurs during the same period from years 1999 to 2009. In detail, there is also a close relationship between the variation of ionospheric TEC and the spatial size of the region.