Summary
Two sets of historical 3-ensemble simulations have been obtained with versions 1.0 and 1.3 of the Australian Community Climate and Earth System Simulator (ACCESS) to examine the effects of ozone change since 1960. The first simulation follows the standard CMIP5 ‘historical’ setup using forcing by ozone, greenhouse gas, aerosol, volcanic and solar terms. In the second simulation, the ozone distribution follows a perpetual 1960 realisation, while the remaining forcing terms use the historical prescription. The two ACCESS versions show some differences in response to ozone forcing, both at the surface and in the upper levels. However, we find that the model well captures observed patterns of long-term surface pressure and temperature changes in summer over Antarctica, and that forcing by ozone appears to play a key role in these changes. In our presentation, we interpret the modelled influence of ozone change at southern high latitudes, and discuss the implications of these changes on the Southern Annular Mode (SAM) pattern, the Antarctic projection of the El Niño-Southern Oscillation (ENSO) and coupling between the troposphere and stratosphere.
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