The basic principles of the empirical model for the maximum height of the ionospheric E region at middle latitudes

The maximum height of the E region in the international reference model IRI-95 is set at the constant value 110 km, which does not agree with the values obtained when measuring this parameter by incoherent scattering and rocket sounding. In fact, the height of the E-layer maximum remains constant only for some time interval around a noon. On the basis of averaged high-accuracy measurements of the height of the E-layer maximum by the incoherent-scattering apparatus at the Kharkov Institute of the Ionosphere, located at the latitude ≈50° N, we have developed an empirical model for the above parameter. This model includes both diurnal and seasonal dependences as well as the dependence on the level of solar activity given by the F_10.7 index. A comparative analysis of this model with other available models for the height of the E-layer maximum near the local noon for all seasons was carried out. A software for the above model using FORTRAN 77 language was developed. Our model can be incorporated into available global models of the ionosphere.