Performance Estimation of NEQUICK 2 Model for Ionospheric Analyses in Kaduna, Kebbi and Bauchi

Abstract

Global Navigation Satellite System (GNSS) data along with the Nequick 2 Model were used to study the monthly TEC profiles for Nigerian GNSS Reference Network Stations for a period of four years (2011 – 2014) as year of high solar activity. These stations fall within the low latitude region. This work examines the performance estimation of Nequick2 model for Ionospheric analyses in Kaduna, Kebbi and Bauchi GPS stations from 2011 – 2014, years of high solar activity. The NEQUICK – TEC were computed using MATLAB programming language and Gopi software. The results obtained showed that the monthly variability of TEC has a pre – dawn minimum followed by an early morning steady increase, an afternoon maximum and then a post sunset gradual reduction in TEC with the equinoctial and solstice months depicting nighttime estimation of TEC. VTEC generally increased from 05:00hrUT and reached its maximum value at approximately 13:00hrUT – 14:00hrUT during all seasons and locations considered. GPS TEC measurement presented a similar behavior for all four seasons with relatively higher amplitudes of monthly maximum in equinoctial months (March, April, September, October), while solstice months (November, December, January, February) present lower value. This could be because the Sun shines directly over the equatorial region during equinoctial months and thus leads to the strongest ionization over these regions, a joint effect of solar zenith angle, the EUV ionization and the magnetic field geometry. Variations in TEC were also seen to show solar dependence.