Fig. 4From: Double-thin-shell approach to deriving total electron content from GNSS signals and implications for ionospheric dynamics near the magnetic equatorIPPs observed by eight GNSS receivers (open circles) in the period from 22 UT, 16 March to 22 UT, 17 March 2014. Orange dots indicate IPPs at a shell height of 300 km and green dots indicate at a shell height of 600 kmBack to article page