Summary
The Southern Hemisphere (SH) is relatively data sparse in terms of ozone monitoring, particularly in the mid-latitudes where there are few long term records. The Australian Bureau of Meteorology possesses continuous datasets from the Australian region dating back to the 1950s (Dobson) or 1960s (ozonesondes), ranging in latitude from the subtropics to the sub-Antarctic. However much of this data requires re-evaluation. Recently the Dobson total ozone record for Melbourne (145° E 38° S) has been reprocessed using a consistent technique from 1978 to the present. Analysis of satellite data from the Merged Ozone Dataset (Stolarski and Frith 2006) reveals firstly, that the location of Melbourne is representative of much of the SH mid-latitudes, and secondly, interannual variability of total ozone in the SH mid-latitudes (from 20° to 60° S ) is determined principally by the "classical" (low frequency) proxies - the 11-year Solar Cycle, QBO and EESC - to a larger extent than the NH, where dynamical factors play a greater role. However, the phase relation between the QBO and ozone is in fact more complicated than generally considered and varies both with latitude and month of the year. Presented here will be a multi-linear regression analysis of the Melbourne Dobson record from 1978 to the present. We find interannual variability in ozone is strongly correlated with the QBO in winter and spring, and with the solar cycle in summer. Once these factors are accounted for the residuals for all months of the year are very consistent with the trend of EESC over this time period. Notably though, the age-of-air assumed for greatest correlation of EESC with the ozone trend is higher in summer (January) than in winter, suggesting the export of air following the breakdown of the Antarctic vortex. Stolarski, R. S. and Frith, S. M.: Search for evidence of trend slow-down in the long-term TOMS/SBUV total ozone data record: the importance of instrument drift uncertainty, Atmos. Chem. Phys., 6, 4057-4065, doi:10.5194/acp-6-4057-2006, 2006.
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