Upgrading IRI by coherent Scatter Radar Data

The ionised part of the mesosphere is also known as the ionospheric D- and E-regions. These parts of the ionosphere crucially depend an the composition of the neutral atmosphere. Hence, a realistic climatological model of the lower ionosphere is not only important for radio wave propagation purposes, but today increasingly constitutes one of the references with which the validity of atmospheric models can be assessed. The empirical data required for such modelling efforts are very limited and most of these data were compiled by staff of the Graz University of Technology. A semi empirical model of the non-auroral lower ionosphere, FIRI, has successfully been established in Graz and is included as one new option to predict the D-region electron density in the International Reference- Ionosphere (IRI) model, the most widely used global ionospheric model. However, this lowest region of the ionosphere (60 to 90 km) is characterised by large variability and a very small volume of reliable direct measurements. Recent comparative results of D-region electron densities showed that large discrepancies still exist between the two new options (Danilov and FIRI) and the standard IRI. Therefore, additional measurement data (primarily the Arecibo Incoherent Scatter Radar data) and more realistic theoretical model results with a data assimilation technique should be considered in the modelling effort for upgrading the non-auroral lower ionosphere model. On the other hand, an auroral empirical model for the upper ionosphere (F- region and plasmasphere) based an the available data of European Incoherent Scatter (EISCAT) radar will be developed. This upper ionospheric model will be combined with the lower auroral ionospheric model (IMAZ) established at the Graz University of Technology within the Lise Meitner scholarship M708 to provide accurate electron density profile predictions at the polar latitudes from D-region to F-region and topside ionosphere. The outcome from this research project will contribute significantly towards improving the current IRI models lower non-auroral and upper auroral ionosphere predictions. At the same time, this work will further help us to yield information an the physical and photochemical processes involved.