EISCAT DATA-BASE FOR IONOSPHERIC MODELING - F-REGION AND TOPSIDE IONOSPHERE

The EISCAT incoherent scatter radar system has now been providing long-term observations of the high-latitude ionosphere for more than a decade, Regular observations of F-region electron density, electron temperature, ion temperature and ion drift with the UHF radar began in 1981. The commission of the VHF radar in 1987 allowed the altitude coverage of such measurements to be extended well into the topside ionosphere. We present an overview of this data base in the context of the International Reference Ionosphere (IRI), including a description of the various experiment modes. Most of these observations have been obtained from the ionosphere approximately overhead of the transmitter at a geomagnetic latitude of similar to 66 degrees N; the remainder cover latitudes from about 5 degrees south to 10 degrees north of the radar location. Emphasis is given to regular observations of the standard ionospheric parameters provided by EISCAT's common programme operations, including an overview of results from positive ion composition analysis. Future prospects related to developments of the radar system are also outlined.