Interannual Variability in the Southern Hemisphere Troposphere

Abstract

Abstract An analysis has been made of the variability of the Australian hemispheric monthly mean analyses at 0000 GMT from May 1972 to January 1978 throughout the troposphere of the Southern Hemisphere. The annual cycle of the variance with respect to time of the zonal mean and the transient eddy components of the monthly geopotential height and geostrophic westerly wind fields are presented as a function of latitude at 1000, 500 and 200 mb. A pronounced quasi-biennial oscillation (QBO) with a systematic pole-ward progression of the anomalies is present throughout the troposphere in the zonal-mean anomaly fields of the height and wind but is absent in the thickness fields. The QBO is clearest at the bottom of the atmosphere and appears to have a barotropic structure.