Climatology of the vertical distribution of ozone over Aspendale (38°S 145°)

Abstract

AbstractData from the first eight years (1965–73) of an ozone sounding programme at Aspendale, Victoria, have been analysed. the mean annual cycle is compared with that derived from similar data from the northern hemisphere. Close agreement is found at similar latitudes in the two hemispheres for the stratosphere at and below the primary ozone maximum, whereas in the free troposphere there is a much smaller seasonal variation in the southern than in the northern hemisphere. There appears to be a marginally higher ozone concentration around the 10 mb region in the northern as compared with the southern summer.The variance about the overall mean vertical distribution has been partitioned between various time scales. the seasonal contribution dominates the variance around the level of the primary ozone maximum, with substantial contributions also in the stratosphere at lower altitudes. the synoptic and other shorter timescale variance (including instrumental ‘noise’) is low above the 50 mb level, where ozone and pressure sensors are least reliable, but it exceeds the seasonal contribution below 70 mb. This suggests that the maximum contribution of the shorter timescales to the variance around the 100 mb level is largely synoptic in character.Significant linear trends in the data are discussed briefly. No evidence for quasi‐biennial or 10 to 11 year solar cycle periodicities is found but significant correlations between ozone variations and the position of the subtropical surface high pressure belt (Pittock's L index) are shown to occur in the stratosphere at and below the level of 50 mb.