Microclimatic response of urban form in the Mediterranean context

The relationship between morphology, climate and energy has always influenced deeply the development of urban settlements. In the Mediterranean context, this process led to compact and dense urban textures, made of highly inertial materials and cladded with bright colors in order to prevent overheating and thermal discomfort. Nowadays, cooling and heating systems relieves the architectural design from climatic constraints. However this has resulted in increased energy consumption, especially in the summer season because of the widespread use of air conditioning systems. The problem is worsened by the Urban Heat Island (UHI) effect. Shape and geometry of a city affect its climate, and so the energy demand at the urban scale (Oke, 2012). The proportions of the urban canyon (height/width ratio) can produce multiple reflections of solar radiation. In addition, the cooling process is decreased during the night due to the low values of the sky view factor. Therefore, in a dense and compact urban texture, higher temperatures can occur especially during the night. The present study seeks to highlight the effect of urban morphology on the UHI intensity in the Mediterranean context. Several morphologically homogeneous textures of Rome and Barcelona are parametrically modelled and compared, by means of the Urban Weather generator tool (Bueno, 2012). The results show that air temperature substantially varies according to different urban morphologies. Understanding the microclimatic behavior of most recurrent urban textures can steer energy and retrofitting policies at urban scale and help to achieve the energy goals set by the EU.