%0 Journal Article
%T GPS-TEC Variation during Low to High Solar Activity Period (2010-2014) under the Northern Crest of Indian Equatorial Ionization Anomaly Region
%A Nilesh C. Patel
%A Sheetal P. Karia
%A Kamlesh N. Pathak
%J Positioning
%P 13-35
%@ 2150-8526
%D 2017
%I Scientific Research Publishing
%R 10.4236/pos.2017.82002
%X The measurements of ionospheric TEC (total electron content) are conducted at a low latitude Indian station Surat (21.16<span style=\"white-space:nowrap;\">¡ã</span>N, 72.78<span style=\"white-space:nowrap;\">¡ã</span>E Geog.), which lies under the northern crest of the equatorial anomaly in Indian region. The data obtained are for a period of five years from low to high solar activity (2010- 2014) using GPS (Global Positioning System) receiver. In this study, we report the diurnal and seasonal variation of GPS-TEC, dependence of GPS-TEC with solar activity, geomagnetic condition and EEJ strength. From the seasonal analysis, it is found that greater values of the GPS-TEC are observed during equinox season followed by winter and summer. The appearance (in the year 2011 and 2014) and disappearance (in the year 2010 and 2012) of ¡°winter anomaly¡± have been observed at the station. From the correlation of GPS-TEC with different solar indices, i.e. solar EUV flux, F10.7 cm solar radio flux and Zurich sunspot number (SSN), it is concluded that the solar index EUV flux is a better controller of GPS-TEC, compared to F10.7 cm and SSN. Further, it is observed that there is no effect of rising solar activity on correlation. Moreover, the percentage variability of GPS-TEC and the standard deviation of GPS-TEC obtained for quiet and disturbed days show that dependence of GPS-TEC on geomagnetic condition is seasonal. Also, there is a positive correlation observed between GPS-TEC and EEJ strength.
%K Total Electron Content (TEC)
%K Equatorial Ionization Anomaly (EIA)
%K Solar Cycle
%K Equatorial Electrojet (EEJ) Strength
%U http://www.scirp.org/journal/PaperInformation.aspx?PaperID=76760