Analysis of TEC Variations in Equatorial Ionization Anomaly Crest Region Over Western China

Using the observation data of GPS stations distributed near the 103.5°E in 2017, the temporal and spatial variation characteristics of Ionospheric Total Electron Content (TEC) in the Equatorial Ionization Anomaly (EIA) north crest over Western China are studied. The results show that the peak TEC of EIA north crest has obvious annual variation characteristics, which is larger in equinox months and smaller in summer and winter months; Compared with previous studies, the latitude of the peak point of the EIA north crest is lower, and the occurrence time is a little later in summer than in other seasons; The TEC in the north crest region shows obvious diurnal and seasonal variation characteristics in time and obvious north-south gradient in space; The north-south gradient of TEC also shows obvious seasonal and diurnal variation characteristics, but there is no obvious relationship between the gradient and latitude in the study area; In case of geomagnetic storms, the TEC responses at different latitudes in the north side of EIA crest region are relatively consistent, but the percentages of decrease or increase in TEC are different with the latitude.