An empirical correction model for low-latitude storm-time ionospheric foF2 considering the equatorial image drift Original Research Article

The equatorial electric field plays an important role in low-latitude ionospheric plasma drift and its distribution at both quiet and disturbed periods, which should be involved in low-latitude ionospheric correction and prediction models. In this paper, an empirical model is established and utilized in real-time ionospheric correction, which contains the affiliation between the ionospheric disturbances and their electric field origins. This model is built using the nonlinear relations between ionospheric foF2 data from two low-latitude ionosondes and equatorial disturbance field data from an empirical model during fifty storms. The performance of the model during twelve intense storms is evaluated and compared with another empirical correction model, STORM. The latter relies on that long-lived negative storm effects are induced by neutral composition changes. The results of our model show that some sharp increase of foF2 could be captured, whereas STORM only gives the probable estimations. The averaged correction error is reduced by 17%, comparing with STORM. This indicates that the disturbance of the electric fields are also important in low-latitude storm-time ionospheric corrections.