Two‐day oscillation of the equatorial ionization anomaly

Abstract

The day‐to‐day variability of the equatorial ionization anomaly (EIA), especially the 2‐day oscillation of the EIA, has recently been studied in China. We suggest that the main driving source of the 2‐day oscillation (or the day‐to‐day variation) of the EIA is a planetary wave with a 2‐day period (or the superposition of planetary waves with different periods). The planetary wave modulates the tidal wind, and this results in the 2‐day oscillation of the EIA via the dynamo effect and fountain effect. This suggestion, derived from the observational data, has been confirmed by numerical simulations.