International Reference Ionosphere
![A sample image showing the relative magnitude of the Total Electron Content of the Ionosphere, as calculated by the IRI 2007. Red indicates a higher electron content; blue indicates a lower electron content.](/Images/godic/202501/20/IRI_TotalElectronContent2614.png")
International Reference Ionosphere (IRI) is a common permanent scientific project of the Committee on Space Research and the International Union of Radio Science started 1968/69. It is the international standard empirical model for the terrestrial ionosphere since 1999. For a specified geographic location, time, and date, the 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. The latest standard is IRI-2012.