Index Overview Urban Heat Island and Outdoor Thermal Comfort for Cooling Singapore

Decades of research have shown that cities are nearly always some degrees warmer than non-urban areas. This phenomenon is one of the clearest examples of inadvertent climate modification by humans. The existence of elevated temperature on street level affects cooling needs. All of this is added to the thermal stresses on humans in hot climates or heatwave events and has prompted considerable research to mitigate aspects of urban heat in cities through urban design measures. The report is divided into three chapters, beginning with investigation about the urban heat effect and combining the following topics i) a historical view of the urban heat research, ii) definitions to tackle the urban heat phenomenon, iii) consideration of four atmospheric layers to describe the spatial and temporal characteristics of urban heat, how they are caused and linked, version to measure and model them. The second chapter deals with the urban effect on human climates. Outdoor microclimates in cities are extraordinarily diverse in space and time. A variety of tools has been developed to understand the complex relationship between humans, climate and the use of outdoor spaces. Therefore, managing the urban climate through urban planning and design solutions for the benefit of human comfort is an important goal for cities worldwide. This chapter describes i) the variables that govern the human energy balance, ii) the options to assess thermal comfort and iii) the summarisation of the most commonly used thermal indices. The report will be concluded with the third chapter, which summarizes the main goals to mitigate urban heat and improve the outdoor thermal comfort