Exploring the Effect of Physical Form on Urban Heat Island Variations

Abstract

Urbanization has had a significant impact on changes in the thermal environment of micro-scale urban spaces such as urban street canyons or blocks. Changes in the micro-scale thermal environment in an urban area have negatively affected the health and quality of life of urban residents and pedestrians and have had economic impacts. Therefore, it is necessary to estimate the influence of the thermal environment of this changing micro-scale urban space and to cope with and improve the damage based on the analysis results. More research is needed to address the limitations of existing studies using an estimation model that reflects only limited meteorological elements and urban geometry. To address these problems, this dissertation conducted three projects based on the urban form and urban thermal environment analysis results of Austin, Texas.

The first study observed and analyzed the micro-scale thermal environment experienced by pedestrians and their behavioral patterns by collecting data using field measurements in the downtown area to identify which urban geometric elements affect the thermal comfort of pedestrians. The results of this study showed that the behavioral pattern trends of pedestrians were somewhat correlated with their level of thermal comfort. In the second study, the micro-scale heat island (MHI) concept was defined, and the MHI model was developed and tested by extracting and reflecting urban geometry and meteorological elements with significant influence from the micro-scale thermal environment using data from field measurements. This MHI model showed about 86.19% explanatory power in estimating the thermal environment of urban canyons. The third study analyzed the effect of variables related to the residential environment in determining housing prices using a hedonic pricing model. Specifically, this study estimated the importance of the outdoor residential thermal environment on housing prices and the quality of life of urban residents in a city. The study results confirmed the economic impact of the urban thermal environment and indicated that the outdoor thermal environment in a residential area plays a role as a significant variable in the determination of housing prices.

This dissertation contributes to the literature by providing a deeper understanding of the relationship between urban design and the urban thermal environment. It also provides an opportunity for cities to review and improve/reset existing planning codes to improve the vulnerable urban thermal environment. Policy and planning codes reflecting this feedback can improve the thermal environment of urban areas and help improve residents' quality of life in terms of socioeconomic aspects.