An empirical model of ionospheric foE over Wuhan

Daytime half-hourly values of the critical frequency of the ionospheric E-layer, f oE, obtained at Wuhan Ionospheric Observatory (geographic 114.4°E, 30.6°N; 45.2°dip), China, during the whole interval of 1957–1991 and 1999–2004 have been used to develop an empirical model. The model, including variations with local time, day number and solar cycle, is in agreement with the observations. A comparison between our model and IRI and Titheridge’s model has also been made. Statistically, our model gives a better performance than IRI and Titheridge’s model because data set is obtained with our own station. Both the IRI and Titheridge’s model overestimate f oE especially in May to September months. Combing with past investigations, we suggest that overestimation of ionospheric parameters by IRI may be a common feature in East Asia. This result is very helpful for both the correction of IRI in East Asia and the development of Chinese Reference Ionosphere (CRI) model.