Prof. Tsuyoshi Honjo

Department of Environmental Science and Landscape Architecture, Chiba University




Application of outdoor thermal comfort map - example of the marathon course of the 2020 Tokyo Olympics



The thermal environment of the 2020 Tokyo Olympic marathon course is 

analyzed by outdoor thermal comfort map which is mainly expressed by 

WBGT and UTCI. To make the outdoor thermal comfort map, we first 

calculated distributions of sky view factor, mean radiant temperature of 

the 10 km x 7.5 km analyzed area in the center of Tokyo. The WBGT is 

about 1 °C lower and the UTCI is about 4-8 °C lower in the shadow of 

buildings from 9:00 to 10:00 than in the sunny side. As a cooling 

method, making shadow is relatively effective method. The variation 

along the course considering the distribution of meteorological data 

within the area is about 0.5 °C WBGT and 1 °C UTCI range, which are 

small value considering the variation with time. The long-term analysis 

on the degree of risk for each hour was also carried out by using one 

point data of the first 10 days of August from 2007 to 2016. The risk 

increased rapidly after 8:00. It will be safer if the marathon race is  

finished before 9:00.