Inter-hourly Variability of Total Electron Content during the quietest days over Akure, within the Equatorial Ionospheric Anomaly region

English Abstract:

The Inter-hourly variability of the total electron content (TEC) was examined using a fixed GPS receiver installed at Akure (7.3⁰N, 5.3⁰E, dip latitude -2.62⁰), based on two years data (Jan 2010-Dec 2011). Akure is a station within the equatorial ionospheric anomaly EIA region. The day to day variability was calculated by converting the observed slant TEC (STEC) value into the vertical TEC (VTEC) for every 1 hr and the differencing (∆TEC) with its corresponding value from the previous day. The result showed the mean monthly TEC value varies from the minimum at 0200 hrs LT to a peak at about 1400 hrs LT and then decreases. There is a clear daily variation which depicts the expected temporal variability. The seasonal variation of the day to day variability of TEC over Akure in both years maximize (> 13 TECU) during Equinoctial months and minimizes (< 8 TECU) during the Solstice months. During equinoxes the study shows that the Inter-hourly variability of TEC in autumnal equinox period is high compared to the vernal equinox period. There is a significant relationship between solar activity and the Inter-hourly variability of TEC over Akure in the two years (2010&2011) with a higher level of dependence on solar activity in 2010.