Modifications of Ionospheric Irregularities Over the African and American EIA Crests During the Major Arctic Sudden Stratospheric Warming of 2013.

This paper investigates the effects of the 2013 major arctic winter sudden stratospheric warming (SSW) event on the modification of small-scale ionospheric irregularities over the equatorial ionization anomaly (EIA) using a chain of GPS receivers within 40º latitudes in the African and South American longitudinal sectors. Our results showed the day-to-day variations of EIA TEC (Total Electron Content) across both sectors during the SSW event. The equatorial region of the South American sector recorded the higher occurrence of severe irregularities and TEC enhancements during the precondition, descending, and peak phase suggesting the possible formation of a reverse plasma fountain or an equatorial peak related to forward plasma fountain induced by the 2013 SSW event. The African sector also recorded the general suppression of irregularities for most days except during the SSW peak phase days with moderate to very intense enhancement of irregularities observed indicating the seasonal modification of small-scale ionospheric irregularities during the January SSW event.