The influence of housing density and urban design on the surface energy balance and local climates of Melbourne, Australia, and the impact of Melbourne's 2030's vision

Urbanised regions of the world are becoming increasingly developed as more and more people make their residency in the heart of the industrial and commercial world. This has led to the formation of distinct urban climates and the development of such phenomenon as the urban heat island, through the alteration of surface characteristics, and can have important implication for human health and comfort. Melbourne, Australia, is a city that is rapidly developing, and the State Government, in order to combat this growth, is promoting a more compact city with increased housing density. The resulting neighbourhoods are likely to influence the partitioning of energy into the convective fluxes and heat storage flux through variations in features such as albedo, thermal properties, moisture availability and roughness, and have important feedbacks to the local climate. To address this question, a study was conducted in Melbourne investigating the surface energy balance of a range of residential housing densities. The aim of this study was to simultaneously examine the fluxes of heat and moisture at four sites of increasing housing density, from rural regions through to high density housing. Eddy covariance measurements were taken for 12 months at a reference tower in a medium density housing area. Simultaneous measurements were then also taken for several months in the southern hemisphere summer/autumn of 2003-2004 and included a Bowen Ratio system over the rural area and two additional eddy covariance measurements at sites of differing housing densities. This paper describes the comparison of surface energy exchange measurements between each of these sites and discusses the impact of these differences on the local climate of Melbourne.