Patterns and Trends in Ionospheric Total Electron Content over Malaysia Region: A 12-Year Analysis

Abstract

The Earth’s ionosphere that ranges from 100 to 1000 km above the Earth’s surface are one of the atmosphere layers in equatorial regions is significantly influenced by solar and geomagnetic activity. This ionized layer quantifies by the total electron content (TEC) that can influence on the propagation of electromagnetic waves that pass through it. Understanding these variations is crucial for improving ionospheric models and mitigating their effects on satellite-based systems. However, detailed studies on long-term TEC variations over Malaysia, located near the geomagnetic equator, are limited. This paper addresses this gap by analyzing a decade of TEC data (2003–2014) from GPS stations across Malaysia. Using GPS data from the Department of Mapping and Surveying of Malaysia and Bernese GPS Sofware, the vertical TEC was computed and analyzed for diurnal, annual, and semiannual trends. The study employed moving averages to suppress short-term fluctuations and highlight long-term patterns. The results revealed a consistent diurnal pattern with a minimum TEC before dawn and a peak post-noon. The study also observed stronger annual variations compared to semiannual ones, except in 2014. Equinoctial asymmetry and the winter anomaly were noted, with the latter occurring during low solar activity phases but absent during higher activity periods. In conclusion, the analysis demonstrates that TEC variations over Malaysia are strongly influenced by solar activity, showing clear seasonal and diurnal patterns. These findings contribute to the understanding of ionospheric behavior in equatorial regions, providing a foundation for improved ionospheric modeling and forecasting. The 12-year data of mean TEC captured the overall climatological features of the ionosphere over Malaysia, which can be used for ionosphere modeling and predicting its variability.