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Response of the Ionospheric TEC at the American low latitudes to SSW and storm-time induced SSW
  • Fashae Joshua Fashae,
  • Olawale Segun Bolaji,
  • A. Babatunde Rabiu
Fashae Joshua Fashae
Bowen University

Corresponding Author:[email protected]

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Olawale Segun Bolaji
University of Lagos
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A. Babatunde Rabiu
National Space Research and Development Agency NASRDA,, Abuja, Nigeria
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Abstract

We investigated the American low-latitude ionosphere around 75°W during the two 2013 sudden stratospheric warming (SSW) events: one in quiet geomagnetic conditions, and the other overlapped by a minor geomagnetic storm using total electron content (TEC) data from 12 Global Positioning System (GPS) receivers. A pair of magnetometers revealing the varying inferred vertical E X B drift and the NASA Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite airglow instrument to understand the global changes in the neutral composition, O⁄N_2 ratio are also used. The late morning inferred downward-directed E X B drift during the first major SSW did not support the varying equatorial ionization anomaly (EIA) signature. However, during the second major SSW, the well-reported and enhanced late morning inferred upward-directed E X B drift relocated a northern EIA crest to higher latitudes. Interestingly, the effect of a minor geomagnetic storm on 17 January 2013 that modulated the ongoing second SSW reduced the maximum inferred upward-directed E X B drift. The second major SSW contribution to the northern crest is higher than photo-ionization and the first major SSW contribution, while each major contribution is higher than minor warming. The minor geomagnetic storm reduced the effect of the second major SSW on the TEC from 58% to 50% and 28% to 20% at the northern and southern crest, respectively. Also, the storm’s overall effect of - 1 % (22 %) leads to a slight reduction (enhancement) in TEC magnitude at the northern (southern) crest.