A STATISTICAL TEC MODEL BASED ON THE OBSERVATION AT WUHAN IONOSPHERIC OBSERVATORY

In this paper, an empirical model of ionospheric total electron content（TEC） is obtained by analyzing the TEC data observed at Wuhan Ionospheric Observatory for a solar cycle （from 1980 to 1990）. In the model, a linear function was applied to describe the relationship between TEC and solar 10.7cm flux index, and took Fourier series analysis to investigate the diurnal and semidiurnal variations of TEC over Wuhan. The agreement between the prediction by this TEC model and the observed TEC data at Wuhan is quite satisfactoryr: the basic trends and the diurnal variations are well reproduced. The overall model prediction error is smaller in the years with low solar activity than in those with high solar activity, smaller in winter and summer than in spring and autumn. and in the morning and at night than in the day time and in the evening. The semiannual of TEC and seasonal anomaly （winter maximum） are also well represented in our TEC model. With the decrease of solar activity, the anomaly is gradually disappeared. In addition, this model is more accurate than International Reference Ionosphere （IRI） model in predicting TEC over Wuhan.