Seasonal Variation of the Ionospheric Total Electron Content, Maximum Electron Density and Slab Thickness Over Wuhan

Half-hourly Total Electron Content （TEC） from Faraday rotation measurement in the EST-Ⅱ satellite and half-hourly foF2 ionosonde data obtained at Wuhan （114.4°E, 30.6°N） from 1980 to 1990 are analyzed to show the seasonal variation of TEC, NmF2 （maximum electron density） and the slab thickness. By analyzing and comparing, the results show that the semiannual anomaly of TEC and NmF2 is obvious in high and low solar activity periods during 1980 and 1990 at Wuhan. The season or winter anomaly of TEC and NmF2 is obvious in high solar activity periods during 1980 and 1990 at Wuhan. The nighttime winter anomaly effect had been observed in the northern hemisphere during solar minimum, which is not observed at Wuhan. The occurrence rate of nighttime enhancements of NmF2 is at maximum in summer during high solar activity periods, but at its minimum during wintertime for low solar activity conditions. The slab thickness is mainly between 200 and 800 kilometers, change of which is small from 0700 LT to 1800 LT and is larger at other time. The observed NmF2 values are used to check the validity of International Reference Ionosphere （IRI） and the single-station model over Wuhan to predict the seasonal variability of this parameter. The effect predicted by the single-station model over Wuhan is better than IRI.[