Maximum wet-bulb globe temperature mapping in central-south Brazil: a numerical study

Heatwaves have been getting more intense and frequent in Brazil. They affect public health, mainly outdoor workers, who are vulnerable to them; therefore, public policies focused on this population must be improved. The aim of the present study was to show the spatial behaviour of the maximum wet-bulb globe temperature (WBGT) in central-south Brazil, at domain 34.5-14.8 degrees S latitude and 61.7-37.3 degrees W longitude. The air temperature under heatwave influence is often extreme in this domain and it can exceed 40 degrees C. The WBGT is based on simulated and observed meteorological data. Numerical simulations were conducted for 9 hr (day shift) in each of the 28 days under heatwave influence. The simulated and observed WBGT values were compared to test the model skill assessment. The maximum WBGT of each grid point took into consideration all the schedules and simulation days. Based on the skill results, the simulated WBGT performance was good, mainly in areas recording a higher WBGT; outdoor workers subjected to moderate and heavy workload must be subjected to control measures or stop working in most central-south domains during periods under heatwave influence. In the most critical cases, outdoor workers should be prevented from heavy workload throughout the entire work shift because they are exposed to almost 8 hr of WBGT higher than 30 degrees C.