Abstract
An upper tropospheric and hemispheric scale data set, resulting from the EOLE constant density balloon experiment (conducted between August 1971 and July 1972) is used to study the spatial variation of various measured and derived fields. The quality and density of the data set is shown to be sufficient for such a study during the Southern Hemisphere spring, summer and autumn of the data period but inadequate during winter.
The stationary modes of the Southern Hemisphere are shown to be relatively weak compared to their Northern Hemisphere counterparts and possess distinct seasonal phase shifts. The transient fields, on the other hand, especially the distributions of momentum flux and kinetic energy, show definite longitudinal anomalies in their seasonal mean properties with magnitudes up to thrice the zonal average. In contrast to the stationary modes, the transient fields show little seasonal variability in position. Furthermore, it appears that most of their magnitude, results from the contribution of a relatively few but extremely intense disturbances which appear to possess a fairly regular variability in the 18–23 day range.
Finally, the persistent climatological cloud bands of the Southern Hemisphere are studied and it is noted that, like the transient anomalies, they too possess little seasonal phase variation. Furthermore, the pole-ward extensions of the cloud bands are shown to lie slightly upstream of the transient momentum flux anomalies and it is suggested that they represent regions of periodic and intense equatorial (northward) wave energy flux, and not the reverse, as is commonly held.
