International Reference Ionosphere 2000

The International Reference Ionosphere (IRI) is the international standard for the specification of ionospheric densities and temperatures. It was dev eloped and is being improved-updated by a joint working group of the Intern ational Union of Radio Science (URSI) and the Committee on Space Research ( COSPAR). A new version of IRI is scheduled for release in the year 2000. Th is paper describes the most important changes compared to the current versi on of IRI: (1) an improved representation of the electron density in the re gion from the F peak down to the E peak including a better description of t he F, layer occurrence statistics and a more realistic description of the l ow-latitude bottomside thickness, (2) inclusion of a model for storm-time c onditions, (3) inclusion of an ion drift model, (4) two new options for the electron density in the D region, and (5) an improved model for the topsid e electron temperatures. The outcome of the most recent IRI Workshops (Kuhl ungsborn, 1997, and Nagoya, 1998) will be reviewed, and the status of sever al ongoing task force activities (e.g., efforts to improve the representati on of electron and ion densities in the topside ionosphere and the inclusio n of a plasmaspheric extension) will be discussed. A few typical IRI applic ations will be highlighted in section 6.