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D. Bilitza
NASA/GSFC, Heliospheric Physics Lab., Code 672, Greenbelt, Maryland 20771
and Space Weather Lab., George Mason University, Fairfax, Virginia
(301) 286-0190,,


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


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) 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 listserver keeps the community informed about model updates, workshops, publication, and other IRI-related matters. To subscribe send a message (the content doesn't matter) to and reply to the confirmation message.

The IRI master copy is held at the NASA's Space Physics Data Facility (SPDF) and Community Coordinate Modeling Center (CCMC) and is updated according to the decisions of the IRI Working Group. The software package distributed by SPDF and CCMC 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-latest: Online computation and plotting through
* IRI-2016: Online computation and plotting through IRI2016web
* IRI-2012: Fortran source code from SPDF's FTP site --- TEMPORARILY UNAVAILABLE
* IRI-2012: Online computation and plotting IRI2012web through Community Coordinated Modeling Center
* IRI-2007: Online computation and plotting through IRI2007web through Community Coordinated Modeling Center
* IRI-2001: PC Windows version from University of Mass. Lowell site
* IRI-2001: Online computation and plotting currently unavailable.

* MIT: Real-time IRI worldmaps and movies (last 24 hours) link
* IPS: Maps of real-time TEC for Autraliasia, North America, Europe, and Japan
* WDC Kyoto: Computation of ionospheric conductivities using IRI90 and CIRA72 models link
* NASA LRC: Models page of LDEF Archive System link
* SPENVIS: The SPace ENVironment Information System developed at the Belgian Institute for Space Aeronomy for ESA/ESTEC link
* SWENET: ESA's Space Weather European NETwork (IRI TEC movies of previous 24 hours) link
* U Leicester: IRI TEC maps link

REFERENCES (some can be accessed as PDF documents):

K. Rawer, D. Bilitza, and S. Ramakrishnan, Goals and Status of the International Reference Ionosphere, Rev. Geophys., 16, 177-181, 1978.

K. Rawer, S. Ramakrishnan, and D. Bilitza, International Reference Ionosphere 1978, International Union of Radio Science, URSI Special Report, 75 pp., Bruxelles, Belgium, 1978.

K. Rawer, J. V. Lincoln, and R. O. Conkright, International Reference Ionosphere-IRI 79, World Data Center A for Solar-Terrestrial Physics, Report UAG-82, 245 pp., Boulder, Colorado, 1981.

K. Rawer and C. M. Minnis, Experience with and Proposed Improvements of the International Reference Ionosphere (IRI), World Data Center A for Solar-Terrestrial Physics, Report UAG-90, 235 pp., Boulder, Colorado, 1984.

D. Bilitza (ed.), International Reference Ionosphere 1990, NSSDC 90-22, Greenbelt, Maryland, 1990. [PDF1: pages 0-84, PDF2: pages 85-end]

D. Bilitza, K. Rawer, L. Bossy, and T. Gulyaeva, International Reference Ionosphere - Past, Present, Future: I. Electron Density, Adv. Space Res. 13, #3, 3-13, 1993. [PDF]

D. Bilitza, K. Rawer, L. Bossy, and T. Gulyaeva, International Reference Ionosphere - Past, Present, Future: II. Plasma Temperatures, Ion Composition, and Ion Drift, Adv. Space Res. 13, #3, 15-23, 1993. [PDF]

D. Bilitza and K. Rawer, International Reference Ionosphere, pp735-772, in: The Upper Atmosphere - Data Analysis and Interpretation, W. Dieminger, G. Hartmann and R. Leitinger (eds.), Springer-Verlag Berlin Heidelberg, 1996.

D. Bilitza, International Reference Ionosphere - Status 1995/96, Adv. Space Res. 20, #9, 1751-1754, 1997.

D. Bilitza, International Reference Ionosphere 2000, Radio Science 36, #2, 261-275, 2001. [PDF]

D. Bilitza, International Reference Ionosphere 2000: Examples of improvements and new features, Adv. Space Res. 31, #3, 757-767, 2003. [PDF]

B. Reinisch and D. Bilitza, Karl Rawer's life and the history of IRI, Adv. Space Res. 34, #9, 1845-1950, doi:10.1016/j.asr.2004.09.002, 2004. [PDF]

D. Bilitza and Reinisch, B., International Reference Ionosphere 2007: Improvements and new parameters, J. Adv. Space Res., 42, #4, 599-609, doi:10.1016/j.asr.2007.07.048, 2008. [PDF]

D. Bilitza, B. Reinisch, and J. Lastovicka, Progress in Observation-Based Ionospheric Modeling: Space Weather, 6, S02002, doi:10.1029/2007SW000359, 2008. [online]

J. Fernandez, C. Mertens, D. Bilitza, X. Xu, J. Russell III, and M. Mlynczak, Feasibility of developing an ionospheric E-region electron density storm model using TIMED/SABER measurements, Adv. Space Res. 46,#8, 1070-1077, DOI: 10.1016/j.asr.2010.06.008, 2010. [PDF]

P. Nsumei, B. Reinisch, X. Huang, and D. Bilitza, Comparing topside and bottomside-measured characteristics of the F2 layer peak, Adv. Space Res.46,#8, 974-983, DOI:10.1016/j.asr.2010.06.027, 2010. [PDF]

Y. Zhang, L. Paxton, and D. Bilitza, Near real-time assimilation of auroral peak E-region density and equatorward boundary in IRI, , Adv. Space Res.46,#8, 1055-1063, DOI:10.1016/j.asr.2010.06.029, 2010. [PDF]

P. Richards, D. Bilitza, and D. Voglozin, Ion density calculator (IDC): A new efficient model of ionospheric ion densities, Radio Sci., 45, RS5007, doi:10.1029/2009RS004332, 2010. [PDF]

D. Bilitza, L.-A. McKinnell, B. Reinisch, and T. Fuller-Rowell, The International Reference Ionosphere (IRI) today and in the future, J. Geodesy, 85:909-920, DOI 10.1007/s00190-010-0427-x, 2011. [PDF]

D. Bilitza, Steven A Brown, Matthew Y. Wang, Jonas R. Souza, and Patrick A Roddy, Measurements and IRI Model Predictions during the Recent Solar Minimum, J. Atmos. Solar-Terr. Phys., 86, 99-106, doi:10.1016/j.jastp.2012.06.010, 2012. [PDF]
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IRI - International Reference Ionosphere

Aurora and Shuttle tail Diagram of Fountain Effect Aurora from LEO IRI International Project Team
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