A Study of Winds in the Ionosphere by Radio Methods

Abstract

Winds in the ionosphere have been studied by a method described by S. N. Mitra using the fading of radio echoes at spaced receivers. A mean daily wind variation of nearly semidiurnal period and about 40 meters per second amplitude has been observed at a 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 of magnetic activity. A similar effect is not observed in the E region except during severe ionospheric disturbances.

Movement of theF-region

“…August 1952 and December 1953, the horizontal speed and direction of movement of the F-region were obtained..it an average virtual-height of 215 km during t• period, the average speed was found to be 362 km/hr, with a mean direction of movement of 135 ø east of north, not quite parallel to the earth magnetic field [8]. The monthly averages of the mean direction revealed a semiannual period, with ß maximum deviation east-of-north around the equinoxes.…”

Ionospheric E-region drifts at Yamagawa during IQSY.

“…These are the high latitude stations, Cambridge (PHILLIPS, 1952) and Ottawa (CHAPMAN, 1953), the low latitude station, Waltair (RAMANA and RAO, 1962) and the equatorial station, Thumba (MISRA, 1973). To examine lunar influence in the E-region drifts at Yamagawa midday (1100-1300 hr LT) values of the drift speeds were grouped into different lunar ages.…”

Drift measurements at Kjeller on the ionosphericFregion

“…A number of research workers have been concerned with the movements in the E layer during the IGY, using the closely spaced receiver method introduced by Mitra [1949]. Only a few papers, however, have been published on the F, layer drifts [Chapman, 1953;Briggs and Spencer, 1954;and Rao, Rao, and Murty, 1959]. Their results may be sum- (c) There exists a positive correlation between the magnitude of the drift and magnetic activity at high latitudes.…”