Abstract
By using six-hourly upper air observations made at 97 stations in the northern hemisphere for ten-day period in September, 1958, the diurnal variations in height of isobaric surfaces, temperatures and winds in the troposphere except the boundary layer were investigated. The prominent features of the diurnal variation in height of isobaric surfaces are negative deviation from the daily mean at about 07 local time for each level, positive one at about 13LT, and the existence of two maxima and two minima at 850mb level. The average deviation of temperature for the air column, from 300mb to 850mb, is remarkably negative at about 07LT and positive in the afternoon.
