Observations of equatorial ionization anomaly over Africa and Middle East during a year of deep minimum

Bolaji, O.S. and Owolabi, O and Falayi, E and Jimoh, E and Kotoye, A and Odeyemi, O and Rabiu, B and Doherty, P and Yizengaw, E and Yamazaki, Yosuke and Adeniyi, J and Kaka, R and Onanuga, K (2017) Observations of equatorial ionization anomaly over Africa and Middle East during a year of deep minimum. Annales Geophysicae, 35. pp. 123-132. ISSN 0992-7689

Abstract

In this work, we investigated the veracity of an ion continuity equation in controlling equatorial ionization anomaly (EIA) morphology using total electron content (TEC) of 22 GPS receivers and three ground-based magnetometers (Magnetic Data Acquisition System, MAGDAS) over Africa and the Middle East (Africa–Middle East) during the quietest periods. Apart from further confirmation of the roles of equatorial electrojet (EEJ) and integrated equatorial electrojet (IEEJ) in determining hemispheric extent of EIA crest over higher latitudes, we found some additional roles played by thermospheric meridional neutral wind. Interestingly, the simultaneous observations of EIA crests in both hemispheres of Africa–Middle East showed different morphology compared to that reported over Asia. We also observed interesting latitudinal twin EIA crests domiciled at the low latitudes of the Northern Hemisphere. Our results further showed that weak EEJ strength associated with counter electrojet (CEJ) during sunrise hours could also trigger twin EIA crests over higher latitudes.