Day-to-Day Variability of Ionospheric Electron Content at Low Latitudes During Minima of 20th and 21st Solar Cycle

Abstract

The day-to-day variability in ionospheric electron content (IEC) has been studied using hourly values of IEC at a number of low latitude stations in Indian, American and Pacific sectors during the minima of 20th and 21st solar cycle. It is found that variability is higher in American sector as compared to that in Indian and Pacific sectors. The variability is significantly larger during E- and D-months then that during J-months at all the stations. The solar activity (Rz) is found to have significant control on the day-to-day variability whereas magnetic activity (A p ) effect is not systematic. Under the geomagnetic disturbances variability is suppressed in nighttime and is enhanced in daytime in Indian and Pacific sectors whereas in American sector the trend is reversed.