Simulating cooling street strategies on urban heat islands effects : an empirical study for Blacktown City, Australia

Australia has ranked as one of the most vulnerable countries to the effects of climate change. The rising trend of temperature is intensifying the creation and extension of urban heat islands (UHI). This paper investigates different cooling street strategies in line with developing resilient Sydney to the effects of climate change. Two different approaches are investigated including, green canopy and cool pavement. A wide range of impacted parameters is examined including Air Temperature, Surface Temperature, Sensible Heat Flux, Sky View Factor, Human Thermal Comfort, and Mean Radiant Temperature. Also, different surface reactions to the sun and shadow were surveyed to investigate the various materials responses to the different levels of shadow. ENVI-met software is adopted to simulate and quantify microclimate processes before and after introducing cooling street strategies. This study demonstrates that replacing asphalt pavement with light concrete pavement reduces surface temperature by up to 20°C. Planting short to medium height trees reduces air temperature by up to 3°C and surface temperature by up to 11°C. Also, human thermal comfort has a direct relationship with the Sky View Factor at daytime. Besides, the study proves that the Mean Radiant Temperature is reduced considerably by both green canopy and light pavement scenarios in the daytime; however, the night time radiant heat does not differ substantially in any of the scenarios. Overall, both proposed initiatives show the positive cooling effects on air, surface, and mean radiant temperature, human thermal comfort, and the heat fluxes in the daytime; however, the cool pavement scenario decreases both daytime and night-time air and surface temperature.