Ionospheric Diurnal Double‐Maxima Patterns Observed by the TEC From Beidou Geostationary Satellites in the Asian‐Australian Sector During 2016–2018

Abstract

AbstractStatistical analysis was conducted to investigate the ionospheric diurnal double‐maxima (DDM) patterns using the total electron content (TEC) from the Beidou geostationary (GEO) satellites. The data were used over the Asian‐Australian sector during 2016–2018. It was found that the ionospheric DDM had the obvious seasonal and latitudinal variations as well as hemispheric differences. The occurrence rate of ionospheric DDM presented a semi‐annual variation with a main peak around the June solstice (local summer) and a secondary peak around the December solstice in the northern hemisphere and equator region, whereas an annual variation with the highest occurrence rate around the June solstice (local winter) was observed in the southern hemisphere. Furthermore, the occurrence rate of ionospheric DDM around the equatorial ionization anomaly crest region was lower than that at other latitudes. There was an anti‐correlation between the occurrence rate of ionospheric DDM and the background TEC, indicating that the drivers, which determine the variations of the background TEC, possibly play an important role in producing the latitudinal and seasonal variations of ionospheric DDM as well. Nevertheless, the causative mechanisms could be different for daytime and post‐sunset DDMs.