Abstract
Using TIME3D-IGGCAS model, we simulated the east–west differences in F-region peak electron density (NmF2) in the Far East mid-latitude region near the longitudinal sectors with very clear zonal variations of geomagnetic declination, and mainly analyzed the influence of the geomagnetic field configuration on the east–west differences. We found that, after removing the longitudinal variations of neutral parameters, TIME3D-IGGCAS can better represent the observed relative east–west difference (Rew) features. Rew is mainly negative (West NmF2 > East NmF2) at noon and positive (East NmF2 > West NmF2) at evening–night. The magnitude of daytime negative Rew is weaker in winter and stronger in summer, and the daytime Rew shows two negative peaks around two equinoxes. With the increasing solar flux level, the magnitude of Rew mainly becomes larger, and the two daytime negative peaks slightly shift to June Solstice. With the decreasing geographical latitude, Rew mainly becomes positive, and the two daytime negative peaks slightly shift to June Solstice. Our simulation also suggested that the thermospheric zonal wind plays an important role in the formation of the ionospheric east–west differences in the Far East mid-latitude region. The observed solar activity dependency of the ionospheric EW differences may be driven primarily by corresponding zonal wind changes with solar activity, whereas the observed latitudinal dependency of the differences is associated with primarily zonal wind and secondarily meridional wind latitudinal variations.
Highlights
The ionospheric spatial structure is an important essential question in the ionospheric research, and has been studied for several decades
Zhao et al (2013) and Zhang et al (2011) both show that the phase of the ionospheric East–West difference depends on the local time, and suggested that it is caused by the coupling of diurnal variation of thermospheric zonal wind and the longitudinal variation of magnetic declination over the Far East regions and US
The absolute magnitude of daytime negative relative east–west difference (Rew) at 50o N is mainly larger than that at 40o N, and two daytime negative peaks slightly shift to June Solstice with the decreasing of geographical latitude
Summary
The ionospheric spatial structure is an important essential question in the ionospheric research, and has been studied for several decades. Zhao et al (2013) and Zhang et al (2011) both show that the phase of the ionospheric East–West difference depends on the local time, and suggested that it is caused by the coupling of diurnal variation of thermospheric zonal wind and the longitudinal variation of magnetic declination over the Far East regions and US.
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