International Reference Ionosphere

International Reference Ionosphere (IRI) is a common permanent scientific project of the Committee on Space Research (COSPAR) and the International Union of Radio Science (URSI) started 1968/69.

For a specified geographic location, time, and date, IRI provides average monthly values for electron density, electron temperature and ion temperature, and the molecular composition of the ions in the range of altitudes from 50 km to 2000 km.

[4] Karl Rawer, the first chairman of the URSI/COSPAR Task group on the IRI (1968–84) specified as goal of the IRI to establish a (monthly) average model of the terrestrial ionosphere based on reliably-measured data obtained with ground- and space-based methods.

IRI used (and still has an option to use) an ITU-R-model that had been developed in respect to radio propagation via the ionosphere, specifying two parameters of which one is narrowly related to the peak electron density and the other to the peak altitude of the ionosphere.

[5] The model can represent variation of these quantities with altitude, latitude, longitude, date, and time of day.

A sample image showing the relative magnitude of the total electron content (TEC) of the ionosphere, as calculated by the IRI 2007. Red indicates a higher electron content; blue indicates a lower electron content.