Articles | Volume 35, issue 1
Regular paper
20 Jan 2017
Regular paper |  | 20 Jan 2017

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

Olawale Bolaji, Oluwafisayo Owolabi, Elijah Falayi, Emmanuel Jimoh, Afolabi Kotoye, Olumide Odeyemi, Babatunde Rabiu, Patricia Doherty, Endawoke Yizengaw, Yosuke Yamazaki, Jacob Adeniyi, Rafiat Kaka, and Kehinde Onanuga

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.

Short summary
Movement of plasma to higher latitudes by EIA is known to relate to eastward electric field/EEJ and thermospheric meridional neutral wind. Experiments from GPS measurements that unveil thermospheric meridional neutral wind effect on plasma transportation in the F region are very few compared with electric field/EEJ. This work includes examples of thermospheric meridional neutral wind effects on GPS TEC measurements and their roles in transportation of plasma compared to electric field/EEJ.