(a) Map of Nigeria showing the IPP tracks of PRNs that detected the 0.52 mHz wave 2200–2330 UT, 17 June 2022. The IPP tracks are progressing northwards. (b), (c) and (d) are the filtered sTEC from LAGO (PRN 14), IBOY (PRN 14), and YLAD (PRN 14), respectively, during the interval 2200–2330 UT, 17 June 2022. The blue markers in the time series visualize the phase progression of the wave crests, while the red markers assist in visualizing the wave troughs. The double arrows are placed to identify the wave cycle in each sub-plot.