A statistical study of single crest phenomenon in the equatorial ionospheric anomaly region using Swarm A satellite

Abstract

Though the Equatorial Ionospheric Anomaly (EIA) is represented by two crests within ±15° latitude, a single crest is also observed in the entire ionosphere. Few studies have addressed single crest phenomena. A statistical study of 2237 single crest phenomenon from the in situ electron density measurements of Swarm A satellite was investigated during December 2013–December 2015. Our analysis focused on local time, seasonal, and both geographic and geomagnetic latitudinal variations. Our results show the following observations: 1 – The maximum number of events peaks mainly in the dayside region around 0800–1200 LT and these occur mainly within the magnetic equator. 2 – The maximum amplitude of the single crests take place most prominently during equinoxes. 3 – The majority of single crests occur in the northern hemisphere. 4 – The seasonal distribution of the events shows that the summer events are located further from the magnetic equator in the northern hemisphere and shift their locations into the southern hemisphere in winter, while spring events are centered along the magnetic equator. 5 – Dayside single crest events appear close to the magnetic equator and more centered on the equator in winter season. 6 – Dawn, night and dusk side events reverse their location from northern hemisphere in summer to southern hemisphere in winter.