Development and Improvement of the International Reference Ionosphere with special emphasis on the topside and extension to the plasmasphere

The International Reference Ionosphere is the international standard for Earth’s ionosphere and recognized as such by the International Standardization Organization (ISO), the Committee on Space Research (COSPAR), the International Union of Radio Science (URSI) and many other organizations. This paper gives a brief introduction of the IRI model highlighting the many uses of the model in many different fields of theoretical and applied sciences and the ongoing efforts to upgrade the climatological IRI model to real-time conditions with updating indices or by assimilating data into the background IRI. The main part of the paper reviews the recent improvements and evaluations of the IRI topside electron density model and presents a new model option for extending IRI to plasmaspheric altitudes. At the heart of this new option is the use of existing empirical plasmasphere models and the Booker (1977) approach that has so successfully been applied in IRI for modelling the plasma temperatures and ion composition. Three empirical plasmasphere models are evaluated as candidates for this extension option: Carpenter and Anderson (1992), Gallagher et al. (2000), and Ozhogin et al. (2012).