Solar Activity Impact on the Earth’s Ionosphere over East Africa during 2009 - 2019

Shumet, Workie

dc.contributor.author	Shumet, Workie
dc.date.accessioned	2025-08-05T06:52:09Z
dc.date.available	2025-08-05T06:52:09Z
dc.date.issued	2024-11
dc.identifier.uri	http://ir.bdu.edu.et/handle/123456789/16831
dc.description.abstract	The ionosphere, a vital layer of the Earth’s atmosphere, plays a significant role in influ- encing radio communication, satellite navigation, and space weather prediction, with its behavior being profoundly affected by solar activity, including EUV flux, sunspots, so- lar radio flux, and geomagnetic activity. Understanding the ionospheric response to these solar and geomagnetic activity changes is crucial for space weather research, particularly as these responses vary spatially and temporally, necessitating extensive study to mitigate their impacts on human technologies. This dissertation investigates the impact of solar and geomagnetic activity on the Earth’s ionosphere over East Africa from 2009 to 2019, during solar cycle 24 and it focuses on the medium- and long-term variations in ionospheric Total Electron Content (TEC) using GPS-derived TEC data from eight stations at low/equatorial latitudes; and solar and geomagnetic indices (EUV, F10.7, SSN, Dst, and Kp) observa- tions. We have applied statistical analysis and quadratic fits with solar proxies (EUV, F10.7, and SSN). Daily mean solar and geomagnetic indices and vertical Total-Electron-Content (vTEC) were analyzed using statistical methods and quadratic fits to identify trends, fore- cast vTEC, and describe its daily, monthly, and seasonal variations. The research highlights that while equinoxes exhibit higher vTEC values compared to solstices, the influence of so- lar activity varies significantly across different timescales. Notable findings include peak vTEC values during equinoxes, especially in March, October, and April 2014, and a strong correlation between vTEC and solar parameters, with 45% to 81% of vTEC variations explained by these indices. The variations of vTEC showed positive associations with the solar parameters. The study reveals that EUV flux has the strongest association with vTEC, particularly during solar maxima, while F10.7 serves as a better proxy for EUV flux. In the predictions of vTEC, the maximum deviations and number of errors were observed during solar maxima years compared to solar minima. The quadratic model effectively captures the dependency of vTEC on solar activity, emphasizing the need for continuous monitoring and modeling of ionospheric conditions to mitigate the impacts on technological systems. Insights into ionospheric behavior enhance the understanding of solar activity’s effects on the ionosphere, contributing to improve space weather prediction models and communica- tion systems in the region, and suggesting future research to integrate these findings into global models. v	en_US
dc.language.iso	en_US	en_US
dc.subject	Physics	en_US
dc.title	Solar Activity Impact on the Earth’s Ionosphere over East Africa during 2009 - 2019	en_US
dc.type	Dissartation	en_US