Assessment of thermal comfort reduction at urban scale using a generalized planning model

Abstract:

As the urban area expands due to the increase in urban population, the importance of improving the urban thermal comfort continues to be raised. We have to evaluate the site in a micro scale for diagnos of the thermal comfort of the urban environment. Micro-scale analysis is generally evaluated at a scale of several hundred meter, so it is performed only for a restricted area. In contrast, this study attempted new approach that produced 99 generalized urban structures and planning techniques (greenery and land cover) and to comprehensively evaluate the thermal comfort in a urban scale. We applied each planning technique to a section corresponding to the target area to evaluate thermal comfort on a micro scale.

The study site is Seoul, the capital city of South Korea, which was classified into three types of urban space based on the biotope map. Finally, we selected eight sites with a size of 200 m × 200 m. Depending on the current status of the site and improvement strategies, the thermal comfort of the city scale was evaluated using a generalized planning model. The temporal range was set to the hottest season, the most heat-sensitive period of the year. In this study, microclimate was simulated through the ENVI-met, and UTCI was calculated through the rBiometeo package.

As a result, the most effective planning was the simultaneous application of two rows of trees and herbaceous cover, which reduced the average UTCI of 1.9 ℃. Site that showed the greatest change in thermal comfort due to improvements in planning was reduced by an average of UTCI 1.3 ℃. This study is meaningful in that use the generalized model to evaluate the thermal comfort for each spatial type in Seoul on a micro scale and to prepare an optimal strategy in urban planning.

This work was supported by Korea Environment Industry & Technology Institute(KEITI) through Urban Ecological Health Promotion Technology Development Project, funded by Korea Ministry of Environment(MOE)(2020002770002).