Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1777967 | Journal of Atmospheric and Solar-Terrestrial Physics | 2007 | 12 Pages |
Abstract
In this paper, we investigate the solar flare effects of the ionosphere at middle latitude with a one-dimensional ionosphere theoretical model. The measurements of solar irradiance from the SOHO/Solar EUV Monitor (SEM) and GOES satellites have been used to construct a simple time-dependent solar flare spectrum model, which serves as the irradiance spectrum during solar flares. The model calculations show that the ionospheric responses to solar flares are largely related to the solar zenith angle. During the daytime most of the relative increases in electron density occur at an altitude lower than 300Â km, with a peak at about 115Â km, whereas around sunrise and sunset the strongest ionospheric responses occur at much higher altitudes (e.g. 210Â km for a summer flare). The ionospheric responses to flares in equinox and winter show an obvious asymmetry to local midday with a relative increase in total electron content (TEC) in the morning larger than that in the afternoon. The flare-induced TEC enhancement increases slowly around sunrise and reaches a peak at about 60Â min after the flare onset.
Related Topics
Physical Sciences and Engineering
Earth and Planetary Sciences
Geophysics
Authors
Huijun Le, Libo Liu, Bin Chen, Jiuhou Lei, Xinan Yue, Weixing Wan,