Seasonal variation of Total Electron Content at equatorial station, Langkawi, Malaysia

GPS signals that propagate through the ionosphere at two L-band GPS frequencies L1 (1575.42 MHz) and L2 (1227.36 MHz) provides an important ionospheric parameter which is Total Electron Content (TEC). The total electron content (TEC) is defined as the total number of electrons integrated along the path from the receiver to the GPS satellite in a column with a cross-sectional area of one square meter. This paper presents the diurnal and seasonal variations of Vertical Total Electron Content (VTEC) at the equatorial latitude station, Langkawi Malaysia using data from GPS Ionospheric Scintillation and TEC Monitori (GISTM). The analysis is presented from January to December 2011 and is presented in three seasons; Equinox (Mac, April, September, October), summer (May, June, July, August) and winter (January, February, November, December). The maximum TEC values are reached between 1300 - 1600 LT; while the minimum TEC occur in the morning. Fot the seasonal variation, analysis the highest TEC is found during the equinoctical months, followed by summer and the lowest TEC are in winter.