Extreme Temperatures and Temperature-Duration-Frequency (TDF) Relationship in Australia

Abstract The frequency and severity of extreme temperatures are changing and therefore, the necessity for the development of design temperatures has emerged. Design temperatures in the form of temperature-duration-frequency (TDF) curves can be utilized to better understand the variability of extreme temperatures with respect to duration and recurrence levels. This study explored the presence/absence of trend and step change in extreme temperatures for nine locations across Australia. Frequency analysis of annual maximum temperatures from 1- to 15-day durations was performed using a generalized extreme value (GEV) distribution under stationary and non-stationary conditions, where the parameters were estimated using the Monte Carlo Bayesian inference approach. Rising trend and step change were observed in Hobart, Adelaide, Perth, Darwin, Alice Springs, Sydney and Melbourne, but not identified in Cairns and Brisbane. Lower variability in design temperatures was found in Cairns and Brisbane, as well as in Darwin and Alice Springs. In contrast, high variability was observed in Sydney and Melbourne, and high design temperatures are reflected in Adelaide and Perth. The approach followed in this study can be applied to any location for TDF curves development and can be utilised to support health risk management of heatwaves, design of infrastructures where temperature related changes may impact the infrastructure, and for preparedness for natural hazards like droughts and bushfires.