A COMPARISON OF THE MAIN IONOSPHERIC PARAMETERSOVER CHINA WITH IRI

By using the ionosonde data observed at several observation stations in China, the observed values of f₀F₂, f₀F₁ are compared with that of IRI-86. The study showed that there exist a systematical and obvious deviations between them. The deviations for E- and F-region are somewhat small. However, the deviation for F₂-region is considerably large, even being up to 60% in some cases. The deviations show clearly diurnal, seasonal and solar activity variations. In general, the relative deviations for f₀F₂ in the night time, summer and active solar zear. Moreover, the deviations become larger with decreasing latitude, and the values calculated from IRIare usually larger than the observed ones.