1Department of Physics, University of Lagos, Akoka – Yaba, Lagos,
2Department of Physics, University of Tasmania, Hobart, Australia
3Center for Atmospheric Research (CAR), National Space Research and
Development Agency (NASRDA), Kogi State University Campus, Anyigba, 270109,
4Institute for Scientific Research, Boston College, Chestnut Hill,
5Department of Physics, Lancaster University, Lancaster, UK
6Department of Physics, University of Ilorin, Kwara, Nigeria
7Department of Physics, Tai Solarin University of Education, Ijagun,
8Abraham Adesanya Polytechnic, Ijebu-Igbo, Nigeria
9Department of Science Laboratory Technology, Lagos State Polytechnics,
10Department of Physics, Afe Babalola University, Ado-Ekiti, Nigeria
Received: 13 Jul 2016 – Revised: 12 Nov 2016 – Accepted: 04 Jan 2017 – Published: 20 Jan 2017
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.
Bolaji, O., Owolabi, O., Falayi, E., Jimoh, E., Kotoye, A., Odeyemi, O., Rabiu, B., Doherty, P., Yizengaw, E., Yamazaki, Y., Adeniyi, J., Kaka, R., and Onanuga, K.: Observations of equatorial ionization anomaly over Africa and Middle East during a year of deep minimum, Ann. Geophys., 35, 123-132, doi:10.5194/angeo-35-123-2017, 2017.