Correlation between Total and Plasmasphere Electron Content and Indexes of Solar and Geomagnetic Activity

Abstract

We study changes in the level of correlation between long-term series of total electron content (TEC), plasmasphere electron content (PEC) and indices of solar and geomagnetic activity. Vertical total electron content data are calculated from phase dual-frequency measurements of global navigation satellite systems. To calculate PEC, we use ionosphere electron content (IEC) measurements from GIRO ionosonde network. PEC is estimated as the difference between TEC and IEC. For the analysis we used data at a typical mid-latitude point (Irkutsk) over 2010–2013 period. We also estimated PEC contribution to TEC depending on local time in different seasons. We calculated correlation coefficients between PEC, TEC, IEC and indexes of helio- (UV, F10.7) and geomagnetic activity (AE, SYM-H). Significant level of correlation is revealed between solar activity indices and daytime TEC, PEC and IEC, with a maximum value of 0.75 for TEC. At night, the level of correlation with solar activity is significantly lower, and it is the highest for PEC (0.46). Correlation with indices of geomagnetic activity is insignificant.