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IRI Workshop Report
International Reference Ionosphere Workshop 2009, Kagoshima, Japan, November 2-7, 2009
The 2009 URSI/COSPAR Workshop on the International Reference Ionosphere (IRI) was held at Kagoshima
University in Kagoshima, Japan from November 2 to 7, 2009. IRI is a joint project of the International Unionof Radio Science (URSI) and the Committee on Space Research (COSPAR). Annual meetings are the primaryvenue for the improvement of the IRI representation of ionospheric parameters, such as electron density,
electron temperature, ion composition and ion temperatures and total electron content (TEC). The specialemphasis of the 2009 Workshop was on (1) regional modeling of the ionosphere and (2)ionosphere/atmosphere/ geosphere coupling studies for improvement of IRI. Other topics of interest for theworkshop included comparisons of IRI with other models and with satellite/ground observations, proposedchanges to the IRI models for improved performance and accuracy, and applications of the model in the many
areas of interest. The workshop homepage with more information and workshop details is at
http://www.ep.sci.hokudai.ac.jp/~iri2009/. The workshop received financial support from the following
sponsors: COSPAR, URSI, Kagoshima Prefecture, Kagoshima City, Hokkaido University, Japan Aerospace
Exploration Agency (JAXA), Kagoshima University, National Institute of Information and Communications
Technology (NICT), Air Force Office of Scientific Research, Society of Geomagnetism and Earth, Planetaryand Space Sciences, Society for Promotion of Space Science, Hombo Shoten Company Ltd, Keirinkan
Company Ltd, AD Company Ltd, Elm Company Ltd. The workshop was a great success with 113 participantsfrom 20 countries including many students and several first time IRI contributors from Japan, China, Taiwan,Korea, Thailand, Malaysia, and Phillipines. The 117 presentations were grouped into one poster session andthree oral sessions covering the topics “Structure and Dynamics of the Ionosphere”, “Solar and Geomagnetic
Variability of the Ionosphere”, and “Ionosphere-Thermosphere Coupling”. A Final Discussion session
reviewed the presented results and came up with proposals for future improvements of IRI.
Papers presented at the workshop were based on data from many ground stations and satellites
including ionosonde stations, incoherent scatter radars, and the Alouette, ISIS, AE-C, Akebono, CHAMP, GPS,ROCSAT-1, Demeter, DMSP, TIMED, IMAGE, COSMIC, and TOPEX/Jason satellites. Radio occultation
measurements from the COSMIC constellation are a promising new data source for improvements of theglobal representation of the topside and plasmaspheric electron density in IRI and were extensively discussed
during the meeting. Comparisons with ionosonde and incoherent scatter radar data are helping to correct andimprove the COSMIC data analysis scheme. Test computations in an IRI ionosphere were also used toevaluate the density re-construction technique. Agreement with ionosonde bottomside profiles is generally
below the 10% level but larger discrepancies are found in the topside when comparing with incoherent scatterradar measurements. Demeter launched in 2004 and still operating is another global data source for IRI
covering the recent extended low solar minimum. First comparisons presented at the meeting show that IRI
electron densities are higher than the Demeter measurements and electron temperatures are lower. Data fromseveral new ionosonde stations were presented at the meeting and compared with IRI. This includes theKorean Anyang station (geographic latitude=37.4N, longitude=127E; geomagnetic latitude=27.7N), the Thai
Chumphon station (10.7N, 99.4E; 3.2S), the Thai Chiang Mai station (18.8N, 98.9E; 13.2N), and theIndonesian Katotabang station (0.2S, 100.3E; 10.1S). The last three are aligned along the 100 degree meridian
and they are part of the South East Asian Low-latitude IOnospheric Network (SEALION) network that also
include the Vietnamese stations in Phu Thuy (21.03°N, 105.96°E) and Bac Lieu (9.30°N, 105.71°E). Datafrom these stations are of particular interest for modeling the Equatorial Anomaly in the Asian sector.
During the Final Discussion session the Working Group decided on several improvements for the next
release of the model. Most importantly the improved representation of the seasonal and solar cycle variationsof the bottomside electron density profile as modeled by Altadill et al. (Ebro Observatory, Spain) based on
ionosonde data will be introduced into IRI. For the F peak the goal is to introduce the neural Network modelsof McKinnell (South Africa) and Oyeyemi (Nigeria) into IRI. These models are based on a much large volumeof data than the original CCIR and URSI models and they have proven to be superior to the older models. At1

auroral latitudes IRI-2010 will benefit from the efforts of two groups using TIMED data. Mertens et al.
(NASA Langley, USA) have used SABER data for the development of an E-peak storm model and Zhang andPaxton (APL/JHU, USA) have developed a model for the auroral particle energies and fluxes and the auroralboundaries based on GUVI data. With the inclusion of auroral boundaries and the description of the expansionof the oval with magnetic activity, the IRI team can now focus on the representation of characteristic structures
like the sub-auroral Ne depletion (trough) and Te enhancement. In the topside the Vary-Chap approach of
Reinisch and Huang (UML) for Ne has reached a high degree of maturity but still needs a global study of therelationship between the topside and bottomside scale height. Several presentations during the workshop
reported on sporadic E occurrence statistics, a parameter not yet included in IRI. This information would beimportant for HF communication, especially over long distances. A good approach would be to model theoccurrence probability at different frequencies.
For the electron temperature IRI-2010 will include the new model that Truhlik et al. (IAP, CzechRepublic) presented at the meeting. The model is based on a large volume of in situ measurements fromdifferent satellites and the main improvement over its predecessor is the inclusion of the solar activity
dependence of Te. The same needs now also to be done for the ion temperature. A better model is alsoscheduled to be included for the molecular ion densities in the bottomside ionosphere. This has long been aweak point of IRI because of the limited availability of reliable data for these parameters. The new model isbased on the well established photochemistry in this region and on normalizing the chemical equilibrium
calculation to the IRI electron density (Richards and Bilitza, George Mason U, USA). In the D-region themodel of Friedrich (TH Graz, Austria) for the transition height from molecular to cluster ions will be a new
addition to IRI.
The meeting program and logistics were expertly handled by the Local Organization Committee
chaired by Shigeto Watanabe (Hokkaido U., Japan). The LOC also organized a very informative scientificexcursion to the Yamagawa Radio Observatory of the National Institute of Information and Communication
Technology (NICT) with a visit and luncheon at the Ibusuki resort. A new feature was the awarding of Best
Student Paper Awards. The first recipients were Y. Y. Sun (National Central U., Taiwan) “The comparison ofLow latitude Spread-F measured by IRI2007, FORMOSAT-1 and GPS ground-based receivers during solarmaximum”, A. Ichihara (Nagoya U., Japan) “Nighttime medium-scale traveling ionospheric disturbances
propagating northward observed by the SuperDARN Hokkaido HF radar and GEONET”, T. Kondo (HokkaidoU., Japan) “Thermospheric zonal neutral wind and zonal plasma drift controlled by F-region dynamo”, N.
Kitamura (Tohoku U., Japan) “Solar zenith angle dependence of the electron density profile in the polar
topside ionosphere during geomagnetically quiet periods in the solar maximum”.
Papers from the 2007 IRI Workshop have now been published in two issues of Advances in Space
Research:Bilitza D., Jan Laštovička, B. Reinisch, (eds.), Ionosphere - Modelling, Forecasting, and Telecommunications I,Advances in Space Research, Volume 43, Number 11, Pages 1595-1846, 2 June 2009.
Reinisch, B., Bilitza D., Jan Laštovička, (eds.), Ionosphere - Modelling, Forecasting, and Telecommunications
II, Advances in Space Research, Volume 44, Number 6, Pages 641-774, 2 June 2009.
The papers from the Kagoshima Workshop will be published in a special issue of “Earth, Planet, Space” (EPS).
The next IRI meetings are planned as follows:2010 COSPAR Scientific Assembly, Bremen, Germany, July 18-25, 2010,
2-day session on IRI in the auroral and polar ionosphere. (MSO: Bilitza)2011 1-week workshop at the Hermanus Observatory in Hermanus, South-Africa (MSO: McKinnell)2013 University of Warmia and Mazury in Olsztyn, Poland (MSO: Krankowski)

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