Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1776729 | Journal of Atmospheric and Solar-Terrestrial Physics | 2013 | 7 Pages |
Average values of ionosonde hmF2 data acquired from an African equatorial station have been used to determine vertical plasma drift (Vz) measurements during period of low solar activity. Pre-noon peak was around 1000 h LT for all seasons. The peak daytime F2 drift is higher during the equinoctial months with an average of 18.1 m/s than the solsticial months (14.7 m/s). At nighttime, Vz is characterized first by upward enhancement around 1900 h LT with a range of 0.3–8.0 m/s, then by a downward reversal. The highest enhancement was recorded in December solstice and start earliest during the March equinox. The peak reversal values are 13.3, 10.7, 9.0 and 4.2 m/s for December Solstice, September Equinox, March Equinox and June Solstice respectively. The observed simultaneous post-sunset rise in hmF2 and in vertical E×B drift together with a sharp drop in NmF2 at all season infer that electrons moving away from the equator are at a region of low recombination loss rate. The abrupt faster drift of the plasma away from the equator as indicated by the pre-reversal enhancement (PRE) in upward plasma drift is responsible for the sharp drop in NmF2 immediately after sunset. Some past results were also confirmed in this work.
► F2 region vertical drifts were inferred using ground-based ionosonde measurements. ► It was done at Ilorin, an equatorial station in the African region. ► Drifts were generated from the time rate of change of the real height. ► We also investigated its variation with peak electron density. ► The year investigated is 2010, a year of low solar activity.