Ionospheric TEC Response to Geomagnetic Storms Occurred on 15-20 March 2013 and 2015 over the Eastern Africa Region

Emmanuel Daudi Sulungu,Christian Uiso

doi:10.11648/j.ajese.20190304.16

Abstract

In this paper we present characteristics of the ionosphere over eastern Africa region in response to two geomagnetic storms of March 2013 and March 2015 that occurred at the same date and time but with different intensities. Ionospheric TEC has been derived from the IGS network of ground based dual-frequency GPS receivers from four stations, namely Eldoret (0.29°N, 35.29°E), Dodoma (6.19°S, 35.75°E), Malindi (2.99°S, 40.19°E) and Mtwara (10.26°S, 40.17°E) within the Eastern Africa region. The interplanetary magnetic field (IMF) Bz and corresponding Dst index, solar wind speed (Vsw) and density (Np) were used to represent the evolution of the storm events. Our results showed that, the behavior of the ionosphere over eastern Africa region during the two geomagnetic storms was similar. During both storms the main phases occurred on 17th of March. However, the main phase of the storm in 2015 had more intensity than that of 2013 but the same duration, and they were followed by a long-duration slow recovery with values that did not return to levels prior to the onset of the storm. The enhancement and reduction of TECv were observed at almost all stations at different times. The results from both storms also show that, there was a pre-reversal enhancement especially at stations that lie close to the equatorial region compared to the stations far from the equatorial region.

Highlights

The major source of the control and the driver of the weather and climate of the near earth space is the sun
When Bz is strongly negative, open field lines are produced by magnetic reconnection between the interplanetary magnetic field (IMF) and the geomagnetic field which allow the passage of mass, energy and momentum from the solar wind to the Earth’s magnetosphere
The solar wind speed abruptly increased from about 420 km/s to about 660 km/s which indicated the commencement of the Storm sudden commencement (SSC)

Summary

Introduction

The major source of the control and the driver of the weather and climate of the near earth space is the sun It drives the magnetosphere, thermosphere and ionosphere of the earth by its energy source [1]. When Bz is strongly negative, open field lines are produced by magnetic reconnection between the IMF and the geomagnetic field which allow the passage of mass, energy and momentum from the solar wind to the Earth’s magnetosphere. This results into more solar wind energy input into all regions of the earth-atmosphere system, resulting into a geomagnetic storm [5]

Objectives

Results

Discussion

Conclusion