Approaches to Ionospheric Modeling, Simulation and Prediction

The ionosphere is a complex, multi-species, anisotropic medium that exhibits a significant variation with time, space, season, solar cycle, and geomagnetic activity. In recent years, a wide range of models have been developed in an effort to describe ionospheric behavior. The modelling efforts include: (1) Empirical models based on extensive world-wide data sets; (2) Simple analytical models for a restricted number of ionospheric parameters; (3) Comprehensive, 3-dimensional, time-dependent models that require supercomputers; (4) Spherical harmonic models based on fits to output obtained from comprehensive numerical models; and (5) Ionospheric models driven by real-time magnetospheric inputs. In an effort to achieve simplicity, some of the models have been restricted to certain altitude or latitude domains, while others have been restricted to certain ionospheric parameters, such as the F-region peak density, the auroral conductivity, and the plasma temperatures. The current status of the modelling efforts will be reviewed