While Global Climate Models (GCMs) in the Coupled Model Intercomparison Project Phase 3 (CMIP3) simulated on average a drier and warmer Australia, the extent to which precipitation and temperature over Australia and the surrounding oceans changed across the models varied significantly. Previous research has found that GCMs with above average sea surface temperature (SST) increase in the west equatorial Pacific Ocean relative to the increase in the eastern Indian Ocean simulated reduced rainfall over Australia. A similar correlation between the tropical Pacific-Indian SST difference and rainfall is found in 26 CMIP5 models, from research supported by the Australian Climate Change Science Program.

To further explore this teleconnection, we examine the separate impacts of SST anomalies of +1K in the west equatorial Pacific and the east Indian oceans on the Australian water budget in using the atmospheric components of two GCMs. The models are CSIRO's Mark 3.5 GCM, which was a member of CMIP3, and the Australian Community Climate and Earth Simulator (ACCESS) version 1.3, in CMIP5. Impacts on the atmospheric water budget, precipitable water content and the horizontal mean-flow moisture flux are analysed. We investigate the different reactions of the water budget of each model in the Australian region to the SST anomalies. The budget is considered over all four seasons with an emphasis on summer, when precipitation is highest. Regions of particular focus are the sites of the anomalies and the Australian Landmass, with northern and southern Australia investigated separately. Special emphasis is put into the differences in the respective models to determine the extent to which the teleconnection is model dependent.