An approach to evaluate the intra-urban thermal variability in summer using urban indicators

Over 50% of world population lives in urban areas and urban planners and managers need tools that allow them to evaluate the performance of the present state and future development of their city in terms of comfort and quality of life. In this paper, an approach to analyze the intra-urban thermal variability is presented. This approach is based on the use of some urban indicators (like green cover ratio, tree cover ratio and building cover ratio) to estimate intra-urban minimum and maximum average summer temperatures. Urban characteristics can be classified by visual or automated interpretation of aerial photography and the indicators can be calculated as the proportion of a specific land use, like vegetation, in a specific buffer area. Then the relationship between urban and temperature indicators can be used to produce thermal maps of the city. The application of this approach and the results of the analysis of intra-urban thermal variability in Florence (Italy) are presented. This approach can help to evaluate the thermal conditions of an urban area, its consequences on thermal comfort, energy consumption of cooling systems, pollution and the mitigation effect that can be obtained by vegetation. Our results suggest that urban indicators can be used to evaluate intra-urban thermal variability as well as other thermal indicators and this information can help urban planners to evaluate the effects of future urbanization scenarios on human health.