SOME FEATURES OF THE IONOSPHERE AT THE CREST REGION OF THE EQUATORIAL ANOMALY

The northern crest of the equatorial anomaly covers Southern China, therefore, the investigation of the ionospheric features of equatorial anomaly at crest is the key for understanding ionospheric characteristics over China. In this paper, 6 related topics are reviewed: 1. Day-to-day variations and the post sunset enhancement of the equatorial anomaly; 2. The movement of the crest; 3. Longitudinal structure of the equatorial anomaly; 4. Intensitive scintillation and fast Faraday fading caused by bubble effects; 5. The ionization ledges in the topside ionosphere and the neutral anomaly; 6. Low-latitude electron precipitation, which is symmetric to the magnetic equator.