Abstract

The Available TEC data from seven (07) GPS stations located in the West African zone were used to determine the calculated temporal distribution of Equatorial Plasma Bubble (EPB) occurrence. We also used the ROTI to detect and evaluate irregularities associated with plasma bubbles. The detection and localization of EPBs were achieved by applying software for the detection and localization of sub-ionized plasma bubbles. The study reveals a variability of EPBs which depend on local time of day, season and solar activity. The diurnal variation of EPBs follows the diurnal variation of the ROTI. It shows EPBs associated with a ROTI higher than 3 TECU/mn at night between sunset around 19.00LT and local midnight. They are lower during the few hours after midnight. Seasonal variation shows a significantly higher occurrence during the two equinoxes than during the two solstices. The annual variation of EPBs occurrence is higher during periods of high solar activity (2001, 2014, 2024) and low or virtually absent during periods of solar minima (2008-2009, 2018-2019).

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