Evaluation of Effective Temperature Scale under Urban Heat Island Formation

Abstract

In this study, the authors evaluated an effective temperature scale, which indicates the thermal comfort level under urban heat island formation in Tokyo for both the present and in ca. 2030. Standard New Effective Temperature(SET) is adopted as an effective temperature scale. The authors call the effective temperature scale for the urban outdoor environment as the USET (Urban SET) in the present paper. The USET maps in the Tokyo metropolitan area are presented and its validity discussed in this study. In order to evaluate the USET, radiation was incorporated through two-dimensional radiation model for urban street canyons. From the present USET maps, it will be shown that the future urban environment in Tokyo (ca. 2030) is no longer tolerable for inhabitants since the USET value exceeds 48°C, which is by far larger than the critical value ever experienced.