Total electron content estimation in low latitude region of East Africa using NeQiuck2 model

Abstract

Modelling ionospheric total electron content (TEC) is important for geodesy, surveying, radio wave propagation, understanding of space weather dynamics and error correction in relation to Global Navigation Satellite Systems (GNNS) applications. In this study, an evaluation of the performance of NeQuick2 ionospheric model in vertical total electron content (vTEC) prediction has been carried out in comparison with GPS measured vTEC at five stations in the equatorial region of East Africa. We have considered a low solar activity year of 2010 and high solar activity year of 2012. The effect of geomagnetic storms has been considered. High correlation between NeQuick2 model predicted vTEC and GPS vTEC for both the year with a low solar activity 2010 and a high solar activity 2012 was observed. The correlation coefficients (R2) between the predicted and measured vTEC at all the stations were in the range (0.884- 0.953) and (0.881- 0.910) in low solar activity year 2010 and high solar activity year 2012, respectively. The model predicted the diurnal vTEC better for the times in the range 01:00–03:00 UT for all the stations than for other times and highest discrepancies were observed between 06:00–16:00 UT over Addis Ababa during the low and high solar activity years. With regard to the monthly and seasonal (March Equinox, June Solstice, September Equinox and December Solstice) vTEC prediction capacity, NeQuick2 model overestimates both the monthly and seasonal mean vTEC values in almost all the stations except Addis Ababa. In this study also, the effects of geomagnetic storm on NeQuick2 model have also been investigated. The measurements indicate that the NeQuick2 model did not respond to the effects associated with geomagnetic storm since vTEC values show no enhancements and oscillations. This shows that there is need to include storm related parameters in the prediction of vTEC using NeQuick2 model. This study provides a basis for the development of vTEC models for predicting space weather effects on telecommunications and setting up early warning for GPS applications over the East African equatorial region. It also forms a significant contribution to ionospheric modelling efforts in Africa.