Effects of Space Weather on the Ionosphere: A Case Study of Geomagnetic Storms During 17-28 February, 2014

Abstract

This study focused on the effects of space weather on the ionosphere during geomagnetic storms for the
period 17 - 28 February, 2014 over the African low latitude region. During this period, a series of in-
terplanetary shocks successively hit the Earth’s magnetosphere, leading to geomagnetic storms. The dual
frequency Global Positioning System (GPS) data was analysed to obtain Total Electron Content (TEC) and
this was used to study the response of the ionosphere to the geomagnetic storms. Positive and negative
ionospheric storm effects were observed during the period of study. These storm effects were discussed in
terms of the Prompt Penetration Electric Field (PPEF), storm induced wind-lifting effect, and Disturbance
Dynamo (DD) electric field. Although these storms occurred during the same period and were all driven
by Coronal Mass Ejections (CMEs), their impacts and associated features on the ionosphere varied due
to different contributing factors to their driving mechanisms. In addition, Rate Of Change of TEC Index
(ROTI) was used to examine the occurrence of ionospheric irregularities. The generation of post-sunset
irregularities were attributed to the Rayleigh Taylor Instability mechanism.