Towards a Cooler Singapore
Urban heat island, together with urban noise and urban air pollution, are the three major environmental challenges of future more livable cities. Urban heat island is defined as the phenomenon that the air temperature in urban area is consistently higher than its rural area (Oke, 1973). It has posed similar heat-related stress and health issues (Kovats and Hajat, 2008; Lo and Quattrochi, 2003; Oikonomou et al., 2012), higher energy costs (Kolokotroni et al. 2012) and downgraded urban living quality (Mavrogianni et al., 2011). Earlier studies in Singapore has identified an urban heat island intensity of 4.5 °C (Wong and Chen, 2006). Another study of Chow and Roth (2006) has reported that the maximum urban heat island intensity occurs in central business districts, low-rise and high-rise residential area around six hours after sun sunsets. It is also found that stronger urban heat islands are observed in May to August during Southwest monsoon. The maximum urban heat island intensity could be as high as 7 °C observed at Orchard Road at 9pm. While many causes of the urban heat island have been identified as in Gartland (2008), the contribution of each component strongly depends on the individual city and its geography. To understand the science behind urban heat island and propose possible countermeasures in Singapore, it is of critical importance to identity each type of heat sources and sinks and their respective contributions.
