Global first-principal 3d modeling of the TEC and its comparison with GPS measurements

In this study the Global Self-consistent Model of the Thermosphere, Ionosphere and Protonosphere (GSM TIP) has been used to calculate the Total Electron Content (TEC). The GSM TIP model was developed in the West Department of IZMIRAN of the Russian Academy of Science. For the given input data the model calculates the time-dependent global 3D structure of the temperature, composition (O2, N2, O), and vector velocity of the neutral atmosphere and the densities, temperatures, and vector velocities of atomic (O+, H+) and molecular ions and 2D distribution of the electric field potential of both dynamo and magnetospheric origin. The distributions of these ionospheric parameters in the near Earth's space have been obtained at altitudes from 80 km up to 15 Earth radii. We present the results of the model calculations of the TEC and their comparison with empirical model for the different seasons of the low solar activity in quiet geomagnetic conditions. We also generate a model constellation of GPS satellites and make comparison of the model exact vertical TEC with "GPS" TEC, calculated using TEC along radio rays for visible satellites.