Mapping GPS-derived ionospheric Total Electron Content over Southern Africa during different epochs of solar cycle 23

Moeketsi, D. M. and Combrinck, W.L. and McKinnell, Lee-Anne and Fedrizz, M. (2007) Mapping GPS-derived ionospheric Total Electron Content over Southern Africa during different epochs of solar cycle 23. Advances in Space Research, 39 (5). pp. 821-829. ISSN 0273-1177



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The Southern African Development Community and the International Global Navigation Satellite Systems Service (GNSS) network of dual frequency Global Positioning System (GPS) receivers provide an opportunity to determine Total Electron Content (TEC) over Southern Africa by taking advantage of the dispersive nature of the ionospheric medium. For this task, the University of New Brunswick (UNB) ionospheric modelling technique which applies a spatial linear approximation of the vertical TEC above each station using stochastic parameters in Kalman filter estimation, primed with data from the Southern Africa GPS network, was used for mapping TEC at South African locations during selected days and hours of different epochs of solar cycle 23. Significant enhancements in the TEC value and features, which could be associated with frequent solar events, are evident around a day of extreme solar maximum. These observations are discussed and further investigated by analyzing the GOES 8 and 10 satellites X-ray flux (0.1–0.8 nm) and SOHO Solar EUV Monitor (26.0–34.0 nm) higher resolution data. Comparison of these physical quantities reveals that for each X-ray flare observed, there is an associated EUV flare event. The latter phenomenon causes photoionisation in the daytime ionosphere which results in significant TEC enhancement. The daytime UNB TEC compared with the International Reference Ionosphere (IRI) 2001 predicted TEC found both models to show a good agreement.

Item Type:Article
Additional Information:New Satellite and Ground Data for IRI and Comparison with Regional Models
Uncontrolled Keywords:Global Positioning System; GPS; International Reference Ionosphere; Ionosphere; IRI; Solar cycle; Solar flares; Solar Terrestrial Physics; Total Electron Content; TEC; UNB model
Subjects:Y Unknown > Subjects to be assigned
Divisions:Faculty > Faculty of Science > Physics & Electronics
ID Code:727
Deposited By: Mrs Eileen Shepherd
Deposited On:03 Jul 2007
Last Modified:01 Aug 2012 10:08
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