Total Electron Content Variations Over Abuja During the Annular Solar Eclipse of September 1, 2016

Abstract

This study is focused on studying the variations of TEC over two GNSS stations in Abuja, Nigeria, during the annular solar eclipse of September 1, 2016. To visualize the effect of the eclipse on TEC, GNSS TEC data for 7 days were used; the 3 days before the eclipse day, the eclipse day, and the 3 days after the eclipse day. Data used in this work were obtained from two GNSS receivers in Abuja. By computing the background diurnal TEC profile from data of the 3 days before and after the eclipse day, the deviation of the eclipse day TEC from the background TEC was estimated. Prominent TEC depressions during and after the eclipse period were observed to be consequences of the moon’s obstruction of the solar radiation. Results from the work reveal that the eclipse was responsible for VTEC depressions up to about 5–7 TECU corresponding to percentage deviations of about 16–24%. There was a lag of about 1 hour from the eclipse peak time to the time when the maximum VTEC depressions were recorded. Secondary VTEC depressions were also recorded about 4–6 hours after the eclipse peak time.

Keywords: eclipse, total electron content, GNSS, TEC, ionosphere