Simultaneous study of drifts at different levels in the ionosphere by the spaced receiver method

Results of simultaneous study of drifts in F1 and F2 regions of the ionosphere measured at Waltair over a period of two years are presented. F2 drift speeds are generally found to be higher than F1 drift speeds measured simultaneously. On a few occasions when f0F1 was high, F2 drift velocity measurements are affected by drifts prevailing in F1 region at that time. It was found that F2 drift measurements are affected by the Es region when F2 region operating frequency is sufficiently close to or even above f Es. F2 region drift gradients have also been estimated by simultaneous study on two frequencies and drift gradients less than 1 m/s per km are reported.