The non-repeating variations of the observed wind in the equatorial stratosphere

To assist in interpretation of large-scale trajectories of fallout, the resultant wind in the stratosphere arising from the interaction of annual and quasi-biennial waves is described in the equatorial zone from 40° N to 40° S for a 3 1/2-year period (July 1957 to December 1960). To illustrate the non-repeating horizontal migrations of the flow patterns from month to month and year to year, 50 mb maps of the zonal component of the mean monthly wind are presented. Meridional cross sections from 100 mb to 10 mb along 180° and also 80° W for the same period show how the zero wind surface and the associated easterly and westerly regimes oscillate across the equator, as functions of height and time.