Seasonal variation in ionospheric electron content and irregularities over Waltair — A comparison with SLIM model

Abstract

Beacon satellite measurements made during 1984–1985 and 1989–1990 at a low latitude station Waltair (17.7°N, 83.3°E) are used to study the diurnal and seasonal variations in ionospheric electron content (IEC) and amplitude scintillations. In 1989–1990, under high solar activity, the daytime IEC shows winter anomaly in the peak values and local time differences in their occurrence. By night, enhancements in IEC and the occurrence of scintillations and spread-F were frequent, particularly at equinoxes. The seasonal variations of the meridional wind direction and phase computed from the SLIM model/1/ compare well with the daytime peak density anomaly and with nighttime IEC over Waltair. A probable effect of neutral winds on the occurrence of ionospheric irregularities is discussed.