The TEC and F2 parameters as tracers of the ionosphere and thermosphere

The more common measurements of the ionosphere are the total electron content (TEC) (measured with the positioning systems) and the parameters of the F-region peak, namely its altitude (hmF2) and its density (NmF2). In this paper, we address the question of using these reduced parameters as tracers of the ionosphere and thermosphere. We make use of a 19 h daylight experiment by the EISCAT incoherent scatter radar based in Tromsphi, Norway. We reduce the full profile measurement of the electron density (between 80 and 425 km) to the TEC, hmF2 and NmF2. Using a 1-D fluid/kinetic model, we reproduce these parameters. Then, by inversion, we retrieve the ionospheric profiles of the electron density, electron and ion temperature and, to a smaller extent, of the ion velocity. With this method, we show that it is in principle possible to evaluate a correction factor for the atomic oxygen. This factor evolves with time. We study the different uncertainties (heat flow, molecular densities, limitations of the model). Finally, we evaluate the contribution of the upper ionosphere (up to 3000 km) to the calculation of the TEC and show that 90% of the TEC is reached when the integration is made up to 1200 km. (C) 2002 Elsevier Science Ltd. All rights reserved.