Correlation distance of ionospheric total electron content in the Indian low latitude region

The Global Positioning System Satellite (GPS) provides an opportunity for studying lonospheric total electron content (TEC). We used GPS TEC data collected at 16 stations across India since 2003 to obtain correlation distance of ionospheric total electron content in the Indian low latitude ionosphere. The correlation coefficients at each local time for 118 pairs of stations are calculated for every month. It has been found that the r = 0.7 correlation distance in longitude is approximately 1500 km in winter months, 1100 km for summer months and 1200 km for equinoxes. The r = 0.7 correlation distance in latitude is approximately 900 km in winter months and 700 km in summer and equinox months. The nighttime correlation distance is found to be greater than the daytime distance.