Last Updated: 02/04/2023


Version: 2012

The International Reference Ionosphere (IRI) is an international project sponsored by the Committee on Space Research (COSPAR) and the International Union of Radio Science (URSI). These organizations formed a Working Group in the late sixties to produce an empirical standard model of the ionosphere, based on all available data sources charter. Several steadily improved editions of the model have been released. For given location, time and date, IRI describes the electron density, electron temperature, ion temperature, and ion composition in the altitude range from about 50 km to about 2000 km; and also the electron content. It provides monthly averages in the non-auroral ionosphere for magnetically quiet conditions. The major data sources are the worldwide network of ionosondes, the powerful incoherent scatter radars (Jicamarca, Arecibo, Millstone Hill, Malvern, St. Santin), the ISIS and Alouette topside sounders, and in situ instruments on several satellites and rockets. IRI is updated yearly during special IRI Workshop, e.g., during COSPAR general assembly). More information can be found in the workshop reports. Several extensions are planned, including models for the ion drift, description of the auroral and polar ionosphere, and consideration of magnetic storm effects.

An IRI Newsletter is published quarterly. Please contact the Newsletter editor K. Oyama if you would like to be included on the distribution list. There is also an electronic mailer with uptodate IRI-relevant information.

The IRI master copy is held at the National Space Science Data Center (NSSDC) and updated according to the decisions of the Working Group. The software package distributed by NSSDC includes the FORTRAN subroutines, model coefficients (CCIR and URSI), and documentation files. The IRI build-up and formulas described in detail in a 158-page NSSDC report (Bilitza, 1990).


IRI requires solar indices (F10.7 daily, 81-day, and 12-month running mean; sunspot number 12-month running mean), ionospheric index (ionosonde-based IG index 12-month running mean), magnetic index (3-h ap, daily ap).


The model produces electron density, electron temperature, ion temperature, ion composition (O+, H+, He+, NO+, O+2), TEC

Model is time-dependant.


  • Global Ionosphere

Space Weather Impacts

  • Ionosphere variability (navigation, communications)


  • Variablility of Plasma Density
  • Ion Drift Velocity
  • Equatorial Anomaly



Code Languages: Fortran


Publication Policy

In addition to any model-specific policy, please refer to the General Publication Policy.