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Firing of ten Aerobee rockets, each carrying 18 to 19 high‐explosive grenades at Fort Churchill, Canada, have resulted in the accurate measurement of temperatures and winds in the atmosphere up to 95 km during November 1956, July, August, and December 1957, and January 1958. One hundred and fifty measurements of temperatures and of winds were made over the period. Each measurement represents the average temperature and wind of an atmospheric layer of about 3‐km thickness. The results show clearly a seasonal variation, with average summer temperatures of 275°K at the mesopeak (about 50 km) and 170°K at the mesopause (about 80 km); corresponding average winter temperatures are 260°K and 230°K. In summer, prevailing winds above 25 km were from the east, usually less than 50 m/sec. In winter these winds were from the west, usually between 50 and 100 m/sec but frequently exceeding 100 m/sec. A breakdown in circulation up to 80 km is indicated by the wind results of two firings on January 27, 1958, where strong northerly and southerly wind components were measured. This phenomenon coincides with the occurrence of sharp temperature increases at stratospheric levels over large parts of the northern hemisphere east of Churchill. Remarkable temperature inversions between 50 and 80 km were measured in all winter firings. These inversions resulted in secondary temperature peaks above 50 km. On December 11, 1957, the temperature at 72 km was about 290°K. In summer, temperatures at 50 km and below at Churchill (59°N) were higher than at White Sands (33°N); above 65 km the Churchill temperatures were lower. This picture is reversed in winter. Only minor diurnal temperature variations were detected. No sound energy from detonations of 4‐pound high‐explosive charges above 95 km was detected on the ground with microphones of 1‐dyne cm2 sensitivity in the frequency range 8 to 25 cycles/sec.

The Eole Experiment with 480 constant level balloons released in the Southern Hemisphere is described. Each balloon, floating freely at approximately the 200-mb level, is a precise tracer of the horizontal motion of air masses, the accuracy of which is limited only by the laminated structure of the stratospheric flow, within an rms uncertainty of 1.5 m sec−1. The balloons were found after 2 months to distribute at random over the whole hemisphere outside the tropics, irrespective of their original launching site. Early results of Eulerian and Lagrangian averages of the Eole wind data are given for describing the mean 200-mb zonal and meridional circulations. The effect of the small scale eddies of two-dimensional turbulence has been studied with respect to the relative eddy diffusion of pairs of balloons and the relative dispersion of triangular clusters. New estimates of the rms divergence of the 200-mb flow are given, together with their scale dependence which was found to be a logarithmic law.

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