The Global Variation of Low Ionosphere Under Action of Energetic Electron Precipitation

Abstract

AbstractThe density in the D region is hard to observe on a large scale, because the density in this region is too low. In addition to solar radiation changes with a sinusoidal period of 24 hr, the energetic electron precipitation (EEP) is the major source for the ionospheric D region. In this study, we utilized observations from NOAA/MetOp satellites to derive the electron density profile from 60 to 150 km under the influence of EEP. It seems that the derived electron profile is roughly consistent with the observed one. Additionally, using above derived method of low ionospheric (D and E regions) electron profile based on the observations of NOAA/MetOp satellites, the actions of EEP on global ionosphere under different level of geomagnetic activity are analyzed. We find that EEP has a significant impact on the electron density in the altitude range from 60 to 90 km in the L ∼ 4.5–8 and MLT ∼ 9–14 regions, particularly during strong geomagnetic activity. A peak in Total Electron Content (TEC) was observed at MLT ∼ 11–12 and L ∼ 5.5–6, exhibiting an enhancement approximately 19.96 times higher than that observed during quiet periods. However, the effects of EEP decrease as altitude increases. The TEC enhancement at altitudes from 90 to 120 km during strong geomagnetic activity is like that at 60–90 km, but only about 2.08 times higher than that during quiet periods. In addition, only a weak increase is detected around midnight at altitudes from 120 to 150 km.