Title
The effect of urban density and vegetation cover on the heat island of a subtropical city
Author(s)
Chapman, Sarah; Thatcher, Marcus; Salazar, Alvaro; Watson, James E.M.; McAlpine, Clive A.
Published
2018
Publisher
Journal of Applied Meteorology and Climatology
Abstract
The urban heat island (UHI) negatively impacts on the health of urban residents by increasing average temperatures. The intensity of the UHI effect is influenced by urban geometry and the amount of vegetation cover. This study investigated the impact of urban growth and loss of vegetation cover on the UHI in a sub-tropical city (Brisbane, Australia) during average and extreme conditions using the Conformal Cubic Atmospheric Model, run at a 1 km spatial resolution for 10 years. The average night-time temperature increase was 0.7°C for the Medium Density urban growth scenario, and 1.8°C for the No Vegetation scenario. During two widespread extreme heat events, the mean maximum increase in urban temperaturesabove the Control was between 2.2°C and 3.8°C in the No Vegetation scenario, and 0.3°C and 1.6°C in the Medium Density urban growth scenario. The results are similar to previous findings for temperate cities, with the intensity of the UHI effect higher at night and during winter than during the day and summer. Vegetation cover had the strongest impact on temperatures, more so than building height and height/width ratio. Maintaining and restoring vegetation, therefore, is a key consideration in mitigating the urban heat island. The large temperature increases found in this study, particularly during extreme heat events, shows the importance of reducing the UHI for protecting the health of urban residents, and this should be a priority in urban landscape planning and design.
Keywords
Climate models;Land surface model;Land use;Urban meteorology;physically-based scheme;climate-change;energy budget;model;australia;intensity;impact;parks;melbourne;summer

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PUB23260