Global Distribution of Persistence of Total Electron Content Anomaly

To better understand the ionospheric morphology response to lithospheric activities, we study the global location preference of the positive and negative total electron content (TEC) anomalies persisting continuously for longer than 24 h at middle and low latitudes (within ±60° N geomagnetic latitudes). The TEC is obtained from the global ionospheric map (GIM) of Center for Orbit Determination in Europe (CODE) under the geomagnetic quiet condition of Kp ≤ 3o during the period of 2005 to 2018. There are a few (less than 4%) TEC anomalies that can persist over 24 h. The conjugate phenomenon is most significant in the eastern Asia to Australia longitudinal sector. The result shows the persistence of the positive TEC anomaly along the ring of fire on the western edge of the Pacific Ocean. The high persistence of the TEC anomalies at midlatitudes suggests that thermospheric neutral wind contributes to the anomaly formation.