ANALYSIS OF LOW-LEVEL CONSTANT VOLUME BALLOON (TETROON) FLIGHTS FROM WALLOPS ISLAND

Abstract

During January of 1960, eight tetroons (constant volume, super-pressured balloons were released from Wallops Island for flight at approximately 3000 ft. The tetroons were tracked by the very accurate AN/FPS-16 radar, thus permitting the delineation of relatively high-frequency tetroon oscillations. It is shown that in the mean the tetroons flew at a constant level, but that flights within an air mass exhibited small-scale vertical oscillations of mean period near 10 min, approximately the ?natural? period of oscillation of air parcels in an atmosphere with the given stability. This finding offers support for consideration of the tetroon as a Lagrangian tracer. Subsequent to passage of a cold front, two tetroons were released 20 min apart and were tracked by different radars. These two flights exhibited nearly identical large-scale vertical oscillations of mean period near 25 min. These pronounced height fluctuations apparently were associated with a vertical motion system moving at a speed of 4 kn in a direction nearly parallel to the frontal intersection with the ground. Statistics derived from the flights indicate that at elevations near 3000 ft the velocity variance is the same in directions along and normal to the mean flow, but that the variance in the vertical is only one-quarter as great. Comparisons with other data intimate that Lagrangian transverse variances and turbulence intensities over the ocean at 3000 ft are nearly an order of magnitude smaller than Eulerian values near the earth's surface.