Longitudinal Variability of the Vertical Drift Velocity Inferred from Ground-Based Magnetometers and C/NOFS Observations in Africa — Oak Academic Publishing
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Longitudinal Variability of the Vertical Drift Velocity Inferred from Ground-Based Magnetometers and C/NOFS Observations in Africa
Department of Geomatics, Higher Technical Teacher Training College of Ebolowa, University of Ebolowa, Ebolowa, Cameroon
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Cardiff School of Education & Social Policy, Cardiff Metropolitan University, Cyncoed Campus, Cardiff, UK
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Department of Meteorology and Climatology, National Advanced School of Engineering, University of Maroua, Maroua, Cameroon
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Laboratoire de Physique de l’Atmosphère, UFR-SSMT, Université Félix Houphouët Boigny, Abidjan, Côte d’Ivoire
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National School of Applied Sciences of Beni Mellal, Sultan Moulay Sliman University, Beni Mellal, Morocco
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Laboratory of Earth’s Atmosphere Physics, Faculty of Science, University of Yaoundé 1, Yaoundé, Cameroon
This study aims at discussing longitudinal effects on the variability of the vertical E × B drift velocity at low latitudes, specifically over African sector. To this effect, observations from ground-based magnetometers and the Ion Velocity Meter experiment onboard C/NOFS satellite are analyzed in conjunc tion with equatorial electric field and neutral wind model estimates under geomagnetically quiet conditions in the years 2012-2013. Notwithstanding the limitation in data over Africa, the combination of ground-based and in-situ observations confirmed the existence of longitudinal differences in the E × B between the Atlantic, Western and Eastern African sectors. This was well reproduced by the equatorial electric field model (EEFM) which showed that during noon, the peak of the equatorial electric field (EEF) was the lowest in the Atlantic sector, with an increasing trend towards the Eastern longitude. The Horizontal Wind Model 14 (HWM14) showed that the eastward zonal (poleward meridional) wind velocity was the lowest (highest) in the Eastern sector. Furthermore, the zonal (meridional) wind increased (decreased) from the Eastern to the Atlantic sector. These results highlight the contribution of the neutral wind velocity in driving the longitudinal difference in the vertical drift velocity over Africa.
KeywordsEquatorial ElectrojetVertical Drift Velocity (E ×B)Longitudinal VariabilityAfrican Sector
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