T. S. Shrungeshwara

By Sridevi Jade and Shrungeshwara T.S.

Continuous Global Positioning System (cGPS) observations spanning 14 years at 24 cGPS sites located in low and mid-latitudes (5–35° N) in the Indian subcontinent are analyzed to extract the ionosphere delay from one-way residuals for each satellite. Absolute integrated electron content (IEC) is the integral of electrons per m2 along the line of sight between the satellite and receiver. Total electron content (TEC) is determined from IEC using elevation mapping function to normalize the variation of the ray path length through the ionosphere based on the GPS satellite elevation angle. In this study, GPS TEC estimates temporally cover two solar cycles (23 and 24) and spatially cover equatorial ionization anomaly (EIA) region and beyond, thus depicting the ionosphere variability in space, time and geographical location. Results capture different phases of solar cycle, EIA, annual, daily, diurnal and seasonal variability of ionosphere in northern hemisphere. This chapter gives significant insights in to the high and random variability of TEC associated with the changes in solar activity, intensity of the sun radiation, zenith angle at which they impinge the earth’s atmosphere, equatorial electrojet (EEJ) and plasma flow.

Part of the book: Multifunctional Operation and Application of GPS