The Urban Heat Island Effect in Singapore
Buildings can inﬂuence climate. The impact is limited for an isolated building but magnifying tremendously for a city. According to Bridgman et al. (1995, p. 15), buildings inﬂuence the urban climate in ﬁve major ways: by replacing vegetated area, presenting blocky and angular buildings, releasing artiﬁcial heat, disposing rainfall rapidly, and emitting contaminants. As a result, the temperature in a built environment is higher than its suburbs and this is known as the Urban Heat Island (UHI) effect. The primary cause of UHI is the rapid urbanization which replaces natural landscape with artiﬁcial hard surfaces, such as building facades, roads, and pavements. These hard surfaces in a built environment re-radiate the solar energy in the form of the long-wave radiation to the surroundings. In addition, absence of extensive vegetation incurs a lack of natural cooling means which can cool the surrounding air through evapotranspiration. Finally, UHI is also aggravated by the lack of moisture source due to the large fraction of impervious surfaces in cities which results in rain water being discharged quickly.