Prospective Changes in Climatology of the CORDEX Domain of Australasia: A Dynamical Downscaling Approach Using RegCM4.6

Although there are increasingly various studies within the frame of CORDEX initiative, most of these studies mainly focus on the domains of Africa, Europe, and the Mediterranean. Therefore, this study presents the regional climate projections for the CORDEX-Australasia domain using RegCM4.6. Projected changes in merely mean temperature and precipitation climatology during the periods of 2011-2040 (near-term), 2041-2070 (mid-term), and 2071-2099 (long-term) with reference to the period of 1971-2000 have been examined for the CORDEX-Australasia domain via regional climate model. Regional climate model runs were employed by using the best parametrizations suggested in the evaluation part of the study. The outputs of two global circulation models (i.e., HadGEM2-ES of the Met Office Hadley Centre, MPI-ESM-MR of the Max Planck Institute for Meteorology) were dynamically downscaled to 50 km under two different Representative Concentration Pathways (RCPs), namely RCP4.5 and RCP8.5. In this respect, seasonal changes in temperature and precipitation climatology of the CORDEX-Australasia domain were analyzed in a higher resolution. The results of the analysis show that there will be increasingly higher temperatures in Australasia towards the end of the century. It is concluded that the mean temperature increase expectation of approximately 1.5-3 ℃ may be around 5 ℃ at the end of the century. On the other hand, the change in precipitation varies greatly depending on the period and sub-region. Average ±20% change in precipitation may occur as 50% or more increases or 30% or more decreases in some places.