Solar Activity and Geomagnetic Storm Effects on GPS Ionospheric TEC over Ethiopia

Kassa Tsegaye,Abraha Gebiregiorgis,Msganaw Aragaw

doi:10.4314/mejs.v11i2.7

Abstract

Ionospheric GPS total electron content (TEC) is an important parameter to monitor for possible Space Weather impacts. The effects of solar activity on TEC at low latitude stations with geographic locations (latitude, longitude) of Addis Ababa (9.040 N, 38.770 E) and Bahir Dar (11.60 N, 37.360 E) in Ethiopia, East Africa in the year of 2015 around peak of solar cycle 24 has been carried out. The data from the two stations was used to study the diurnal, monthly and seasonal variations of TEC and its dependence with solar activity and space weather effects. These observations were investigated and further discussed with an analysis of Disturbance Storm Time (Dst) and Ap indices, solar radio flux (F10.7cm) and sunspot number during the period of 2015. During the period of low or high sunspot number, that provided GPS ionospheric TEC builds up slowly or quickly. The obtained results reveal TEC undergoes diurnal and seasonal variations, daily variation of TEC value at both stations sharply increases to its peak from 0900 -1500 UT and decreases around 1600 - 0700 UT. Seasonal variations showed that TEC maximizes during the equinoctial months and least in summer over the two stations. In all seasons the maximum value of TEC in Addis Ababa is higher. The effects of geomagnetic storms on TEC values have been found negative and positive output.

Highlights

As mankind has become increasingly dependent on technology, understanding of the effects of the Space Physics phenomena on human technology, termed Space Weather, has become increasingly necessary (Jakowsky et al, 2002)
During February, March and April 2015 the magnitude of the total electron content (TEC) is better than the rest days of other months at 0000 - 2300 universal time (UT)
The three months (March, April and February) TEC value during 2015 at both stations is extremely differ from other months TEC value

Summary

INTRODUCTION

As mankind has become increasingly dependent on technology, understanding of the effects of the Space Physics phenomena on human technology, termed Space Weather, has become increasingly necessary (Jakowsky et al, 2002). Because of the sensitivity of the science as stated above and the insufficient studies about ionospheric variability in Ethiopia, East Africa, we are motivated to investigate effects of solar activities and geomagnetic storms on GPS ionospheric TEC over Ethiopia by using Addis Ababa and Bahir Dar GPS stations in the year of 2015, which is around peak of solar cycle 24. The computation of reliable vertical total electron content (VTEC) of the Ionosphere is at the same time a useful and challenging goal It is useful because, in both Science and Technology fields, they can provide valuable information concerning space weather events, empirical model predictions and user navigation improvement, among others. Because of the sensitivity of the science and the insufficient studies about ionospheric variability in Ethiopia, East Africa, we are motivated to observe the effects of solar activities and space weather events by using ground-based GPS receivers over this sector with recent data. The main objective of this study is to investigate effects of solar activities and geomagnetic storms on GPS ionospheric TEC over Ethiopia by using Addis Ababa and Bahir Dar GPS stations in the year of 2015, around peak of solar cycle 24

DATA AND METHODOLOGIES

RESULTS AND DISCUSSION

CONCLUSIONS

CONFLICT OF INTERESTS