Analysis and simulation of heat index for developing a heat alert system over Thailand

This study aims to develop a real-time heat illness alert system (HIAS) for monitoring outdoor working environment related to heat. Using monthly Interim ECMWF Re-Analysis and hourly weather data from Thai Meteorological Department (TMD), the system applies Steadman Method to calculate heat index (HI) and issues warning when the predefined conditions are met. The results show that Thailand's daily temperature distribution is influenced by solar declination. Seasonal effects such as moist air in wet season will also drive up the apparent temperature. The developed HIAS system uses hourly weather data from TMD's weather stations in proximity of 5 air force bases. System tests showed that the system can calculate heat index and provide real-time heat illness risk warning by showing an appropriate color on warning display. The prototype systems can be effectively used to provide a safer working environment for military personnel. While this study focuses on the risk from heat exposure, it also provides a guideline for development of other types of warning systems such as those for heavy precipitation, flash flood, and water overflow.