WBGT Forecasts for Preventing Heat Strokes in Japan

Heat Stroke caused by hotter summer related to Global Warming and heat island effects becomes a hot subject of discussion especially in cities. In Japan hundreds people died because of heat strokes in one year and recently the number of deaths of aged people older than 65 years old has been increasing. WBGT(Wet-bulb Globe Temperature: Yaglou and Minard, 1957) is a standard index to set down the rule for workers or athletes also in Japan. And WBGT is calculated from dry-bulb temperature, wet-bulb temperature and globe temperature. The dry-bulb temperature is quite common and the wet-bulb temperature can be calculated by dry-bulb temperature, humidity and pressure, but globe temperature had not been estimated. Through the observations of temperature, humidity, wind speed, sun radiation and globe temperature, we formulate the equation to estimate globe temperature with dry-bulb temperature, sun radiation and wind speed. And using numerical forecasts issued by JMA(Japan Meteorological Agency), we try to issue WBGT 3 hourly forecast for the day and the next day in order to reduce the risk of heat stroke. We open the forecasts through the web site (http://www.nies.go.jp/wbgt/) from July to September to alert the risk of heat stroke experimentally. And we examine the difference of WBGT and dry-bulb temperature caused by the difference of ground surface and the height from the ground theoretically in order to warn the risk of heat stroke especially for young children and their parents.