Effects of Urban Heat Island mitigation in various climate zones in the United States

Abstract

This research investigates the Urban Heat Island (UHI) effect in different climate zones in order to analyze the efficacy of UHI mitigation strategies. A base case urban canopy model was developed using statistical urban district information for Houston, Texas. The Urban Weather Generator (UWG) was employed to simulate the UHI effect during the hottest week of the Typical Meteorological Year (TMY3). Two case studies were conducted to represent the impacts of UHIs on the different climate zones. First, a case study was conducted to compare the UHI effect in various climate conditions. We controlled the urban morphology to estimate the effects of the climate zones on UHIs, but the UHI intensity outcomes still considerably differed from one another, ranging from 1.25℃ to 4.35℃. Second, UHI mitigation strategies such as roof vegetation, trees, and grass coverage ratio were tested to measure their sensitivity in different climate conditions. The results show that green roofs have a marginal effect on UHI mitigation in high-rise urban morphology, while increases in grass and tree coverage ratios were effective, especially in hot climates. The results also indicate that the strategies employed should consider the climate’s characteristics in order to encourage a more sustainable built environment.