TITLE:
Longitudinal Variability of the Vertical Drift Velocity Inferred from Ground-Based Magnetometers and C/NOFS Observations in Africa
AUTHORS:
Messanga Etoundi Honoré, Paul Obiakara Amaechi, Augustin Daïka, Diaby Kassamba Abdel Aziz, Mohamed Kaab, César Biouele Mbané, Zouhair Benkhaldoun
KEYWORDS:
Equatorial Electrojet, Vertical Drift Velocity (E × B), Longitudinal Variability, African Sector
JOURNAL NAME:
International Journal of Geosciences,
Vol.13 No.8,
August
25,
2022
ABSTRACT: 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 conjunction 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.