PARAMETERS:

Electron density, electron temperature, ion temperature, ion composition (O⁺, H⁺, He⁺, NO⁺, O⁺₂), ion drift, ionopsheric electron content (TEC), F1 and spread-F probability

BRIEF DESCRIPTION:

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 (members list and on world map) 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 provides monthly averages of the electron density, electron temperature, ion temperature, and ion composition in the altitude range from 50 km to 2000 km. Additionally parameters given by IRI include the Total Electron Content (TEC; a user can select the starting and ending height of the integral), the occurrence probability for Spread-F and also the F1-region, and the equatorial vertical ion drift.

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 Workshops (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 irregularly. Past and present issues are available from the Newsletter homepage. Please contact the Newsletter editor K. Oyama if you would like to be included on the distribution list.

An IRI electronic mailer keeps the community informed about model updates, workshops, publication, and other IRI-related matters. Information on how to subscribe and prior mailings are available from the IRI electronic mailer homepage.

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).

NSSDC ID: MI-91J

REFERENCES (some can be accessed as PDF documents):