ELECTRON DENSITY PROFILES OBTAINED BY EMPIRICAL PROCEDURES

Abstract

A review of ionospheric studies is presented with a view to providing some theoretical background on the variations of the ionosphere with altitude, time of the day, season of the year, geographic or geomagnetic location and solar activity.

The conventional method for investigating the ionosphere is also discussed to show the interrelationship between the ionospheric parameters and to provide the background knowledge for interpreting the results.

The relevant theory on global phenomenological ionospheric models is examined including the International Reference Ionosphere (IRI)to facilitate the comparison of the results of electron density profiles obtained.

The study of low-latitude electron density profiles has been carried out on semi-empirical basis in order to compare the results of observed ionospheric parameters in this region With the International Radio Consultative Committee's (CCIR) predictions.

Ionospheric data from two low-latitude stations at different geographic/geomagnetic locations are drawn for the months of January/February, June and September representative of Winter and Summer seasons respectively. Electron density profiles are computed for different solar activities and time of the day with the relevant ionospheric data as inputs.

The spatial and temporal variations of the low-latitude ionosphere are investigated by a general consideration and evaluation of the experimental electron density profiles obtained. These results are compared with those obtained from International Reference Ionosphere (IRI) models.

The results of the study revealed further the possibility of using simple analytic semi-empirical model to reproduce representative profiles of the equatorial ionosphere. The importance of further comparisons with additional sets of electron density profiles under different solar-geophysical conditions at more ionospheric stations is highlighted.