Abstract/Summary

The Wet Bulb Globe Temperature (WBGT) is an international standard heat index used by the health, industrial, sports and climate sectors to assess thermal comfort during heat extremes. Observations of its components, the globe and the wet bulb temperature, are however sparse. Therefore WBGT is difficult to derive, making it common to rely on approximations, such as the ones developed by Liljegren and colleagues (2008,WBGT_Liljegren) and by the American College of Sports Medicine (WBGT_ACSM87). In this study, a global dataset is created by implementing an updated WBGT method using ECMWF ERA5 gridded meteorological variables and is evaluated against existing WBGT methods. The new method, WBGT_Brimicombe, uses globe temperature calculated using mean radiant temperature and is found to be accurate in comparison to WBGT_Liljegren across three heatwave case studies. In addition, it is found that WBGT_ACSM87 is not an adequate approximation of WBGT. Our new method is a candidate for a global forecasting early warning system.