Dynamically downscaled simulations of Australian region tropical cyclones in current and future climates

Abstract

A fine resolution atmospheric model is used to analyse changes in the climatology of tropical cyclones over the Australian region under future climate conditions. This model gives a good simulation of the observed climatological intensity distribution, which has been difficult to obtain in many previous studies. Projected changes for the end of the 21st century show a decrease of approximately 30% in numbers of tropical cyclones. There is an associated poleward shift in the regions of both genesis and dissipation of tropical cyclones. The dynamical mechanisms for this change are found to be changes in the vertical velocity and relative vorticity, which may be linked with anticipated future changes in the tropical circulation. Additionally, there are some small but significant future decreases in the percentage of mid-range intensity storms and a slight increase in the percentage of the most severe storms. Copyright 2011 by the American Geophysical Union.