Analysis of Correlation between ROTI and S4 Using GAGAN Data

As ionosphere is one of the most prominent sources of error, ionospheric TEC and scintillation studies are necessary for improving the performance of a navigation system. In this paper, the behavior of the correlation coefficient (rho) between Rate of TEC Index (ROTI) and amplitude scintillation index (S-4) over low latitude station Hyderabad (Latitude: 17.44 degrees (deg.) N, Longitude: 78.74 degrees (deg.) E) for different seasons is analyzed. Also, the analysis is extended for nearly same longitude stations like Trivandrum, Bangalore, Bhopal, Delhi and Shimla for the higher values of total K-p index for 60 days (most disturbed 5 days per month). For Trivandrum (lowest latitude station), it is observed that both S-4 and ROTI are high as compared to Bangalore, Bhopal, Delhi, and Shimla. It is found that there is a good correlation between the temporal variations of ROTI with S-4 after post sunset hours. The confidence intervals for computed correlation coefficients at 95% confidence level are also given.