Verification of Ionospheric Models by TEC and Satellite Measurements

Despite a huge stream of the experimental data, allowing us to estimate ionospheric parameters in near real time, necessity for ionospheric modeling does not decrease. Transition to developing a model of the most changeable structure - the main ionospheric trough (MIT) was now outlined. The latest model is the Karpatchev and co-authors's model of 2016 which concerns night winter conditions (the most probable occurrence of a trough). The model is constructed according to vertical sounding and measurements of plasma frequency on satellites. As the increasing role in an estimation of ionospheric conditions is played by the total electron content (TEC), in the present paper the problem of comparison of TEC behaviour with the MIT model was put. It is shown, that TEC always shows presence of the trough however its form is more smoothed. Good enough conformity exists for longitudinal dependence of MIT, but latitudinal dependence of the TEC trough is closer to data of low-orbit satellites. Testing of the International Reference Ionosphere model is a traditional problem. In the present paper, the basic attention was given to conformity of ionospheric and plasma frequencies at height of the satellite and to use TEC. It is shown, that the usage of TEC increases accuracy of definition of critical frequencies in 1.5 times in comparison with the model in a range 5° on a latitude and 90° on a longitude from ionosondes.