No abstract

SUMMARYA systematic study of the winds in the upper atmosphere has been carried out during the 5-yr period 1953 to 1958. At heights of 85 to 100 km regular prevailing and periodic tidal wind components have been resolved. Components of the prevailing wind of about 20 m sec-' towards east are observed during the summer and winter months, with similar westward components during spring and weak westward winds in autumn. Large southward components of approximately 20 m sec are observed during the summer. The amplitude of the semi-diurnal periodic wind is also about 20 m sec-', and this component can usually be represented by a vector which rotates in a clockwise direction with constant amplitude twice every 21 hours. Large departures from this simple model occur at certain times of the year. Measurements of the 24-hr and 8-hr periodic wind systems are also described, and an upper limit of 2 m sec-l is determined for the lunar semidiurnal wind component.

No abstract