A study of winds in the ionosphere by radio methods

Winds in the ionosphere have been studied by a method due to S.N. Mitra using the fading of radio echoes at spaced receivers (Proc. IEE, London, 111, 43, p. 441; 1949). A mean daily wind variation of nearly. semi-diurnal period and about 40 meters per second amplitude has been observed at à nominal height of 110 km (Region E), The wind variation is consistent with the explanation that it is due to tidal oscillations of the atmosphere. A wind variation consistent with that expected from lunar atmospheric tides has also been detected at this level. The winds in the F region appear to increase in velocity with an increase in magnetic activity. A similar effect is not observed in the E region except during severe ionospheric disturbances.