Simulated east–west differences in F-region peak electron density at Far East mid-latitude region

Abstract

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 (R ew) features. R ew is mainly negative (West NmF2 > East NmF2) at noon and positive (East NmF2 > West NmF2) at evening–night. The magnitude of daytime negative R ew is weaker in winter and stronger in summer, and the daytime R ew shows two negative peaks around two equinoxes. With the increasing solar flux level, the magnitude of R ew mainly becomes larger, and the two daytime negative peaks slightly shift to June Solstice. With the decreasing geographical latitude, R ew 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.

Keywords

• Ionospheric east–west difference
• Ionospheric longitudinal variation
• Ionospheric region anomalies
• Mid-latitude ionosphere
• Ionosphere–thermosphere coupling