Lunar tidal oscillations in the horizontal ionospheric drift at the equator

The effect of lunar tides on the apparent ionospheric drift velocity (V) for an equatorial station Thumba (0.6°S dip) is computed by using nearly six years of data at fixed solar hours. Significant tides are observed in the E-region drifts, particularly around 12.00 hr and in the F-region drifts around 15.00 hr.A good correlation in the phases of the lunar tides in H and V is found to exist, suggesting a strong electrojet control of the horizontal ionospheric drift around these hours.