Estimating the Daytime Vertical E×B Drift Velocities in the F-region of the Equatorial Ionosphere Using the IEEY and AMBER Magnetic Data in West Africa

Abstract:

In this paper the daytime vertical drift velocity in the F-region of the equatorial ionosphere was estimated from the magnetic effect of the equatorial electrojet (EEJ) in the West African longitude sector. In this purpose, the geomagnetic data recorded during the International Equatorial Electrojet Year (IEEY) from 1993 to 1994 and that provided in 2013 by the African Meridian B-field Education and Research (AMBER) network were used. For the IEEY project, data from Sikasso (11.34° N, 5.71° W, 0.12°diplat), Tombouctou (16.73° N, 3° W, 6.76 diplat) and Lamto (6.23° N, 5.02° W, -6.27 diplat) were considered. For the AMBER project data from Conakry (10.5°N, 13.71°W, -2.69°diplat) and Abidjan (4.60° N, 6.64° W, -8.54° dip) were considered. The vertical drift velocity was inferred from the EEJ contribution (ΔH) in the geomagnetic field horizontal component. The estimated noontime seasonal averages are respectively V_d= 10.95 m/s and V_d= 9.46 m/s for March and September equinoxes; V_d= 8.75 m/s and V_d= 8.27 m/s for December and June solstices. The daytime vertical drift velocity was found to be larger in equinoxes than in solstices. These values are in agreement with the results of previous studies in the same longitude sector.