Ionospheric modelling

This paper describes various techniques of ionospheric modeling including their applications. Modeling efforts are broadly divided into two categories, viz empirical modeling and theoretical modeling. It is emphasized that different formulations are used for global description of peak parameters and the vertical distribution of electron density under empirical modeling. Efforts made in India in developing regional models are given a special attention. Theoretical models based on the evaluation of physical processes are described with special emphasis on the low latitude modeling. It is important to obtain realistic measurements of input parameters such as solar radiation flux, neutral winds and electric fields besides a neutral atmospheric model. Recently there have been efforts of evolving a global theoretical model covering high, mid and low latitudes including their special features. A low latitude semi-empirical model based on empirical formulation of theoretically calculated data is described.