dc.description.abstract |
The thesis delves into a comprehensive examination of Total Electron Content (TEC) data
gathered from both GPS and Ionex models in Bahir Dar, Ethiopia, spanning the years
2008 and 2015. This investigation meticulously dissects TEC variations across multiple
time scales, including hourly, daily, monthly, seasonal, and solar cycle analyses. Through
this scrutiny, noteworthy distinctions emerge between the TEC values derived from the
Ionex model and those obtained from GPS readings, shedding light on the dynamic nature
of electron density estimations within the ionosphere. Notably, the analysis uncovers day to-day fluctuations in TEC values, underscoring the intricate interplay between the Ionex
model and GPS data. Furthermore, the monthly assessments unveil remarkable
similarities in TEC distributions between the Ionex and GPS datasets, drawing attention to
specific anomalies that manifest during certain months. These fluctuations in TEC values
throughout the months reveal subtle discrepancies in peak TEC values, serving as
indicators of seasonal variations in ionospheric electron density. These variations are
likely influenced by a myriad of factors, including solar activity, geomagnetic
disturbances, and atmospheric dynamics. The research underscores the inherent variability
in processes impacting TEC estimations, stressing the critical significance of accounting
for seasonal variations in ionospheric modeling and predictive endeavors. While the study
acknowledges the significant influence of various factors on seasonal variations in Ionex
and GPS TEC values, it does not delve into the specific role of neutral wind dynamics in
this investigation. During periods of solar minimum and maximum activity, substantial
differences in Ionex TEC and GPS TEC values are observed, with notable peaks around 5
and 22 TECU in 2008 and 2015, respectively. These variations are attributed to a diverse
array of phenomena, such as solar flares, heightened ionization levels, geomagnetic
storms, and technological influences. The study advocates for enhanced TEC evaluations
to deepen the understanding of ionospheric dynamics, particularly in light of the intricate
interplay of factors affecting TEC values during different phases of solar activity. By
conducting more rigorous TEC assessments, researchers can gain a more profound insight
into the complex mechanisms at play within the ionosphere, thereby advancing our
knowledge of this crucial aspect of Earth's atmosphere. |
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