Parametric description of thermospheric ion composition results

The Cospar sponsored activity for the preparation of an international reference ionosphere (IRI) provides the first extensive international effort for the development of an empirical ionospheric model between the altitudes of 100 and 1000 km. Although significant global characteristics of the electron density and temperature distributions have been identified through extensive satellite and ground-based measurements, the global characteristics of the individual species of the ion composition remain to be described. Because of the inherent complexity of the ion composition, direct high-resolution measurements are required to describe the behavior of both the major ions and the trace constituents. By virtue of the excellent spatial coverage afforded, the polar-orbiting Ogo satellites have provided a unique opportunity for accumulating an ion composition data base needed for a statistical input to the IRI.