The dramatic and damaging effects of tropical cyclones (TCs) are already clearly apparent in the current climate, making potential changes in the frequency or intensity of these storms in the future of immense interest. The present study concentrates on the south-west Pacific where many island nations are strongly affected by TCs through loss of life and damage to crops and infrastructure due to heavy rainfall, strong winds and storm surge. The Weather and Research Forecasting (WRF) model is used to downscale to a resolution of 4km; firstly from reanalysis data and secondly using output from a global climate model (GCM). Some recent TCs such as TC Yasi (QLD), TC Pam (Vanuatu) and TC Winston (Fiji) are downscaled to show the ability and limitations of this methodology.

Since global climate models are relatively coarse and unable to properly resolve TCs, they are unable to reproduce the observed intensities. However, they are able to simulate TC-like features. Using a detection algorithm allows us to detect these TC-like vortices directly from the climate model data. In order to analyse changes in intensities, the individual events detected in the GCM (ACCESS1.0) were downscaled using WRF. The ability of WRF to simulate the TCs in the current climate is assessed and changes in wind speed, pressure, size and rainfall under a future climate scenario are examined. Preliminary results show an increase in the size and intensity of TCs occurring in the future. These will have likely knock-on effects on waves, storm surge and coastal erosion.