Abnormal distribution of ionospheric electron density during November 2004 super-storm by 3D CT reconstructions from IGS and LEO/GPS observations

Using time-dependent 3D tomography method, the electron density distributions in the low-latitude ionosphere during November 2004 super-storm are reconstructed from GPS observations of joint ground-based IGS network and onboard CHAMP/GRACE satellites. The reconstructed electron densities are validated by satellite in situ measurements of CHAMP and GRACE satellites. It is indicated by computer tomography (CT) reconstructions that the long-lived positive storm phase during the first main phase of the storm (November 8) is mainly attributed to enhancement of electron density in the upper F region above the F2 peak. It is found by the CT imaging that the top-hat-like F2-3 double layers occurred in the equatorial ionization anomaly region during the main phase of the storm (at forenoon of November 8). The structures of column-like enhanced electron density are found at the time near the minimum of Dst and in the longitudinal sector about 157 degrees E, which extend from the topside ionosphere toward plasmasphere, reaching at least about 2000 km as high. Their footprints stand on the two peaks of the EIA.