COSPAR/URSI Working Group on the International Reference Ionosphere

Report/ Dieter Bilitza and Bodo Reinisch

The IRI Working Group is preparing the release of the IRI-2006 model that will include a number of improvements and new additions. For the topside electron density profile two options are now offered: (1) the ‘old’ IRI model with a correction term obtained from comparisons with ISIS/Alouette topside sounder data, and (2) the NeQuick model developed by Radicella (ICTP, Italy) and Leitinger (Graz, Austria) and their colleagues based primarily on ionosonde data and also some topside sounder data. A very promising effort towards future improvements in this area is being undertaken by Reinisch (UML, USA) and colleagues combining ionosonde, topside sounder, and IMAGE/RPI data for the development of a continuous ionosphere-plasmasphere electron density model. One of the new additions in IRI-2006 is a model for the plasmaspheric electron temperature that was developed by Kutiev (Bulgaria), Oyama (ISAS, Japan) and colleagues from the analysis of Akebono satellite data. Other new additions include the regional spread F occurrence probability model by Abdu, Souza et al. (INPE, Brazil), and the stormtime equatorial ion drift model by Scherliess et al. (USU, USA).

The Working Group organized a well-attended session on the modeling of ionospheric temperatures and ion composition during the Paris COSPAR General Assembly in 2004. Selected papers from the session will be published in a dedicated issue of Advances in Space Research (ASR) this Spring. The most recently published ASR IRI issue is Number 9 of Volume 34 (Quantifying Ionospheric Variability) which includes 35 papers from the 2003 IRI Workshop in Grahamstown, South Africa. The 2005 IRI Workshop was organized by the Ebro Observatory, Roquetes, Spain as part of their centennial celebrations. The week-long meeting brought together IRI developers and users (48 scientists from 18 nations) under the general topic of ‘New Satellite and Ground Data for Comparisons with Regional Models’. Ground and space data sources were evenly represented including data from many ionosondes, and from most incoherent scatter radars, and from the satellites Akebono, CHAMP, DMSP, GPS, Hinotori, IK-19, IK-24, IMAGE, ISIS, JASON, Ohzora, ROCSAT, TIMED, TIROS/NOAA, and TOPEX, and from several rocket flights. Of special interest were proposals for better representation of ionospheric parameters in the middle ionosphere and for the description of ionospheric variability. COSPAR’s financial support for the IRI meetings is thankfully acknowledged. Several other international and national organizations provided financial support for this meeting.

Future IRI workshops are planned for Buenos Aires, Argentine in October 2006 and for Prague, Czech Republic in July 2007. The Institute of Atmospheric Physics in Prague will organize the July 2007 workshop as a joint meeting with the European COST 296 Action.

Four new members were elected into the IRI Working Group: Prof. Shin-Yi Su from the Institute of Space Science and Center for Space and Remote Sensing Research of the National Central University in Chung-Li, Taiwan; Dr. O. Obrou from the University of Cocody in Abidjan, Ivory Coast; Dr. P.K. Bhuyan of the University of Dibrugarh in Dibrugarh, India; Dr. Man-liang. Zhang, Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing, PR China.