International Reference Ionosphere

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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) 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 ionospheric altitude range (see details below).

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 flown on many 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.

The IRI model and software is updated according to the decisions of the IRI Working Group. The software package includes the FORTRAN subroutines, model coefficients (CCIR, URSI, IGRF), indices files (IG_RZ.DAT, APF107.DAT) and README and LICENSE files. The IRI build-up and formulas are described in detail in a 158-page NSSDC report by Bilitza (1990) (PDF accessible in REFERENCES).

An IRI listserver keeps the community informed about model updates, workshops, publication, and other IRI-related matters. To subscribe send a message to info@irimodel.org with 'subscribe IRI your_email_address' in the SUBJECT line and your name, affiliation and mailing address in the body of the message.

PARAMETERS:
Electron density, electron temperature, ion temperature, ion composition (O⁺, H⁺, He⁺, N⁺, NO⁺, O⁺₂, Cluster ions), equatorial vertical ion drift, vertical ionospheric electron content (vTEC; a user can select the ending height for the integration along the electron density profile), F1 probability, spread-F probability, auroral boundaries, effects of ionospheric storms on F and E peak densities

INPUTS:
Required: 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 indices are found internally by IRI for the user-specified date and time. In the case of F10.7D, F10.7_81, F10.7_12, R_12, and IG_12 a user can input his/her own values.
Optional: The user can provide a number of input parameters and the IRI profiles will than be adjusted to these input parameters:
F2-peak height (hmF2) or propagation factor M3000F2, F2-peak plasmafrequency (foF2) or electron density (NmF2)
F1-ledge height (hmF1), plasmafrequency (foF1) or electron density (NmF1)
E-peak height (hmE), plasmafrequency (foE) or electron density (NmE)
D-ledge height (hmD), plasmafrequency (foD) or electron density (NmD)

HEIGHT RANGE:
Electron density: daytime: 65-2000km, nighttime: 80-2000km
Electron and ion temperature: 60-2500km (IRI-95 option: 60-3000km)
Ion composition: 75-2000km (DS95/DY85 option: 80-2000km)

AVAILABILITY:
* Fortran source code: IRI-2016 (10/13/2021), IRI-2012, IRI-2007, IRI-2001, COMMON FILES for all versions
NOTE: Besides the files that come with each version you also need to download the COMMON FILES and INDICES FILES.
NOTE: The IRI output arrays are explained here
NOTE: The switches available in the IRI code to turn on/off certain dependencies are explained here
* Solar and Magnetic Indices (daily updates, 8:00 EST, provided by David Themens ECHAIM website): APF107.Data IG_RZ.DAT
* Solar and Magnetic Indices (updated twice a year): INDICES FILES (10/05/2021)
* Online computation and plotting at CCMC (HELP): IRI-2016 (03/26/2018), IRI-2012, IRI-2007
NOTE: Please consult the HELP file for an explanation of the different inputs, outputs and options.
NOTE: Please use/customize the Fortran code for large volume computations, because overuse may result in service discontinuation.
NOTE: The program iritest.for can be easily adapted to a specific application.
NOTE: The IRI-2012 distribution also includes iriorbit.for and iriorbitmax.for for calculating IRI parameters along a satellite orbit.
* Real-time IRI foF2 & hmF2: IRTAM IRI Real-Time Assimilative Mapping with GIRO digisonde data
* MATLAB version: IRI-2012
* pyglow - Python wrappers for IRI-2012 and IRI-2016

FREQUENTLY ASKED QUESTIONS: FAQ

RELATED LINKS:
* MIT: Real-time IRI worldmaps and movies (last 24 hours) link
* IPS: Global and Regional Maps of real-time TEC using IRI link
* WDC Kyoto: Computation of ionospheric conductivities using IRI90 and CIRA72 models link
* SPENVIS: The SPace ENVironment Information System developed by the Belgian Institute for Space Aeronomy link

REFERENCES (some can be accessed as PDF documents):
List of IRI-dedicated issues of Advances in Space Research

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. [PDF]

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]

I. A. Galkin, B. W. Reinisch, X. Huang, and D. Bilitza, Assimilation of GIRO data into a real-time IRI, Radio Sci., 47, RS0L07, doi:10.1029/2011RS004952, 2012 [PDF]

D. Bilitza, D. Altadill, Y. Zhang, C. Mertens, V. Truhlik, P. Richards, L.-A. McKinnell, and B. Reinisch: The International Reference Ionosphere 2012 - a model of international collaboration, J. Space Weather Space Clim., 4, A07, 1-12, doi:10.1051/swsc/2014004, 2014. [PDF]

D. Bilitza, D. Altadill, V. Truhlik, V. Shubin, I. Galkin, B. Reinisch, and X. Huang, International Reference Ionosphere 2016: From ionospheric climate to real-time weather predictions, Space Weather, 15, 418-429, doi:10.1002/2016SW001593, 2017 [PDF]

D. Bilitza, IRI the International Standard for the Ionosphere, Adv. Radio Sci., 16, 1-11, https://doi.org/10.5194/ars-16-1-2018, 2018.