Correction of Key Parameters of the IRI Model Based on Ionograms of Topside Satellite Sounding of the Ionosphere

The paper considers a method for determining the total (up to the height of the satellite) altitude distributions of the electron plasma frequency
$(f_{N}(h)$
profiles) in the ionosphere from ionograms of topside satellite sounding. The main attention is paid to the IRI model used to represent the
$f_{N}(h)$
profile in the bottomside ionosphere. It is shown that in order to obtain
$f_{N}(h)$
profiles based on the IRI model that are close to real ones, it is necessary to correct the IRI model according to the parameters characterizing the profile in the F2 region. For their precise determination, a method is proposed for solving a system of two integral equations linking these parameters with the group paths of signals reflected near the maximum of the F2 region in the topside ionosphere and the group paths of signals reflected from the Earth's surface. Using the example of calculations
$\text{of}f_{N}(h)$
profiles based on the ISIS-2 ionograms, it is shown that the use of the method can significantly improve the parameters and shape of the profile in the F2 region. Using refined IRI profiles, total profiles up to the height of the satellite are constructed.