A Comparative Analysis of GPS Ionospheric Scintillations Observed in Northern and Southern Equatorial Anomaly Regions in 2013-2014

This study carries out a comparative analysis of Global Positioning System (GPS) ionospheric scintillations observed at four GPS scintillation monitoring stations near the equatorial anomaly crests (+/- 15 degrees geomagnetic latitude). Three of them are situated in Brazil, namely, Presidente Prudente (PRU2, 22.12 degrees S, 51.41 degrees W), Macae (MAC2, 22.38 degrees S, 41.79 degrees W) and Sao Jose dos Campos (SJCE, 23.21 degrees S, 45.86 degrees W). The other one is located in the Hong Kong area, namely HKHT (22.21 degrees N, 114.26 degrees E). The comparisons are made by analyzing the occurrence of amplitude scintillations at diurnal, monthly and seasonal time scales, patch duration and spatial distributions of scintillations observed during May 2013 to April 2014. Moreover, the rate of Total Electron Content index (ROTI) is used to characterize ionospheric irregularities. The results show that the amplitude scintillations mainly occur between 20:00 LT and 2:00 LT in both southern and northern hemispheres. PRU2 is observed to have the most frequent occurrences of diurnal amplitude scintillations and MAC2 has the least frequency. On a monthly basis, the southern hemisphere stations (PRU2, MAC2 and SJCE) observe most scintillations in the October 2013 to March 2014, while the northern hemisphere station HKHT observes the most scintillations in the March equinox month. Over the four stations, most patch durations of scintillations are within 30 minutes and the scintillations with the longest lifespan occur in the March 2014 (spring equinox month). Spatially, the distribution of scintillation occurrences is highly correlated with that spatial distribution of ROTI >= 0.5 TECu/min.