An analysis of the meteorological variables leading to apparent temperature in Australia: Present climate, trends, and global warming simulations

• Trends of air temperature and apparent temperature are calculated for Australia.
• Three data-sets are used for trend analysis: observational, reanalysis and CMIP3.
• The majority of Australia had warming temperatures and/or apparent temperatures.
• ENSO, SAM and their influence on thermal comfort are also explored for Australia.

This study is a comprehensive analysis of thermal comfort and apparent temperature around Australia. It includes a long-term historical trend analysis using observational weather station data, in which it was found that eight out of the ten chosen urban locations experienced warming trends in temperature and/or the apparent temperature over the second half of the twentieth century. Annual trends in temperature and apparent temperature were studied spatially across Australia using high resolution ERA Interim reanalysis data over the period 1979 to 2010. The reanalysis revealed that generally the apparent temperature is warming faster than the air temperature, amplifying the expected exposure to discomfort due to global warming in the subtropical region.Future apparent temperature trends were explored using high resolution Coupled Model Intercomparison Project 3 model data to assess the impacts of global warming on human comfort. A best practice model for the Australian climate was used as well as best case and worst case scenario models selected using the Commonwealth Scientific and Industrial Research Organisation Representative Climate Futures framework. It was found that at 2070 using the A1B emissions scenario the temperature is projected to warm faster than the apparent temperature by up to 1 °C in central Australia, suggesting that the cooling power of the wind can partially offset the impacts of global warming. This occurs in conjunction with the accelerated drying predicted to occur in many areas of Australia in future climates.Finally, the impact of the El Niño Southern Oscillation and the Southern Annular Mode on the spatial characteristics of the temperature and apparent temperature around Australia was studied. This revealed that the inherent atmospheric humidity variability of these large-scale processes resulted in milder thermal comfort conditions across Australia regardless of whether the temperature was anomalously warm or cool. Using an apparent temperature framework, this study looks into many facets of the Australian climate uncovering knowledge that is useful for risk assessments as well as future urban planning.