Morphology of Equatorial Ionospheric Scintillation at 327 MHz

64-70The morphology of ionospheric scintillation at 327 MHz in the equatorial belt is studied by using the radio telescope at Ootacamund. The scintillation indices deduced from strip chart records are compared with the global nocturnal scintillation model developed by E J Fremouw and C L Rino of Stanford Research Institute [Radio Sci(USA), 8(1973) 213]. While there is hardly any disagreement in the seasonal pattern between the model and the Ooty observations, a significant departure is observed in the diurnal pattern. Instead of a single peak around midnight, as predicted by the model, the observations show a major peak at 2230 hrs LT followed by another minor peak at 0330 hrs LT. However, the most spectacular departure is observed in the solar activity variation. The model predicts steep variation of solar activity while the observations pertaining to low-to-medium solar activity show a trend which is almost independent of solar activity. Morphology of scintillation at other stations in the equatorial belt is briefly brought out for comparing with the Ooty observations