ESTIMATION OF VERTICAL AIR MOTIONS IN DESERT TERRAIN FROM TETROON FLIGHTS

Abstract

Low-level, constant volume balloon (tetroon) flights made from Yucca Flat in the Nevada Proving Grounds of the Atomic Energy Commission are utilized to yield an estimate of the nature and magnitude of vertical air motions in desert areas. It is found that during the day the tetroons oscillate as much as 10,000 feet in the vertical with vertical velocities often exceeding 5 kt., whereas during the night the vertical oscillation are on the order of 100 feet and vertical velocities seldom exceed 0.5 kt. There are indications that during the day, at this particular site, helical circulation patterns exist with axes parallel to the north-south oriented valley floor and with alternating circulation sense across the valley, while during the night the small vertical oscillations are more nearly tied to the local topography. Pure mountain influences on the tetroon trajectories could not be clearly delineated owing to the tremendous vertical oscillations associated with solar heating.