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THE AFRICAN EQUATORIAL IONIZATION ANOMALY RESPONSE TO THE ST. PATRICK'S DAY STORMS OF MARCH 2013 AND 2015
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  • Bolarinwa John Adekoya,
  • Olawale Bolaji,
  • Bolarinwa J. Adekoya,
  • Shola John Adebiyi,
  • Babatunde O. Adebesin,
  • Stephen O. Ikubanni
Bolarinwa John Adekoya
Olabisi Onabanjo University

Corresponding Author:[email protected]

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Olawale Bolaji
University of Lagos
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Bolarinwa J. Adekoya
Olabisi Onabanjo University
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Shola John Adebiyi
Landmark University
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Babatunde O. Adebesin
Landmark University
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Stephen O. Ikubanni
Landmark University
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Abstract

The ionosphere around the Equatorial ionization Anomaly (EIA) region exhibits a complex dynamic and responds markedly to the solar-magnetospheric energy and momentum. In this paper, the hourly response of the EIA structure in the Africa to St. Patrick’s Day storms of March 2013 and 2015 is investigated using data obtained from a chain of GPS receivers located in the African region. The TEC variations were characterized based on the convective magnetospheric dynamo fields, the neutral wind circulation, and zonal electric fields. Generally, the result indicates that the TEC variations were consistent with the different directions of the interplanetary fields during the different phases of the storms. We observed reverse EIA structures in the main phase of the storm of March 2015, suggests to be related to the intense PPEF and strong equatorward wind which imposed westward zonal electric field at the equator. Similar equatorial peak observed during the recovery phase is associated to DDEF, poleward wind and plasma convergence. Furthermore, TEC variations also indicate hemispheric asymmetries during the storms. During the main phase, the TEC is more enhanced in the northern hemisphere during the storm of March 2013, this was reversed during March 2015. We observed equatorial peak during SSC period of the storm of March 2013, while EIA structures are generally weak in March 2015 event. This may posit that ionospheric pre-storm behaviour is better understood when the IMF-Bz and electric field are weak. The observed distinctive response avowed the peculiarity in the electrodynamics intricacy in the Africa sector.