ANALYSIS OF SUMMER THERMAL COMFORT IN JAPAN FROM 1980 TO 2020 USING UTCI

Abstract

 There is growing concern about the health risks posed by global warming and the heat island effect. In order to properly assess health risks, it is important to evaluate them in terms of thermal comfort. This study evaluated the long-term trend of the Universal Thermal Climate Index (UTCI) in Japan in summer from 1980 to 2020, and the relationship between UTCI and the number of heat stroke patients. Regarding the long-term trend of UTCI, increasing trends were detected at 109 out of 140 AMeDAS sites. Thermal comfort had worsen since the rise in air temperatures, MRT, and decreasing wind speeds. Regarding the relationship between UTCI and the number of heat stroke cases, we found that the UTCI threshold at which the number of heat stroke cases drastically increase differs across cities geographically and lower in northern cities than southern cities.