Ionospheric Models for Prediction and Forecasting

Abstract

A comprehensive knowledge of the Earth's ionospheric structure and dynamics, in particular its refractivity profiles, is necessary to guarantee the effective operation, planning, and management of numerous radio communication and navigation systems. These can be based either on: (1) advanced models coupled across the space-terrestrial environment, providing detailed knowledge of conditions and good predictions; or (2) specific well-targeted services that provide products like specification data, post-event analysis, long-term predictions, instantaneous nowcasting and short-term forecasting generated in real or near real-time in response to available observations. Since its discovery, many models of the Earth's ionosphere have been developed. These fall into several classes and include the D, E, and F regions at low, middle, and high-latitudes. Ionospheric models can be divided into three main groups:1. theoretical, parameterised, and empirical models that define not only the ionospheric electron density profile but also the different profile parameters in terms of ionospheric characteristics at every point on the globe, for example foE, foF1, and linear or polynomial foF2 versus R 12 ; 2. assimilation models for a full 3-D electron density profile; 3. empirical and physical models or methods for 2-D global, regional, and local mapping of the characteristic ionospheric parameters both for long-term prediction and nowcasting in the field of radio propagation and navigation (e.g. CCIR and URSI maps of ITU-R, ionospheric COST actions maps, etc.).The first two groups of models are more general and are therefore presented in this Chapter, while the third group of models and methods are more practical and are described in the following Chap. 6.