Abstract
An analysis of total electron content (TEC) variations detected over southern Africa has been performed. We included two days with high lightning activity, one day with low lightning activity and one day with a geomagnetic storm. An attempt to obtain a better understanding of lightning as a source mechanism is motivated by the fact that lightning couples energy directly to the mesosphere and lower ionosphere through quasi-electrostatic (QE) and electromagnetic pulsed (EMP) fields and through upward propagating gravity waves that transfer energy from the site of lightning into the ionosphere. Geomagnetic indices, GPS data from six dual frequency GPS reference stations and lightning data from the WorldWide Lightning Location Network (WWLLN) have been used to explore the origin of the TEC variations detected. The analysis reveals periods of TEC variations of similar to 1 TECU on geomagnetically quiet days which correspond to periods of intense lightning activity in the regions. The TEC variations on the days with high lightning activity appear to have more high-frequency TEC variation content than days with low lightning activity.