Urban Heat Island Mapping Based on a Local Climate Zone Classification : a Case Study in Strasbourg City, France

The Urban Heat Island (UHI) effect is characterised by higher temperatures in cities than in rural surroundings. This phenomenon leads to increased health risks in urban dwellers, particularly in the context of global climate change. It is essential to consider its spatial variability to propose efficient UHI mitigation strategies. The Local Climate Zone (LCZ) scheme is a climate-based classification that can accurately capture UHI intensities according to the urban area characteristics. In this study, an LCZ classification has been established for the city of Strasbourg by using a vector-based method that relies on a large vector database composed of land cover and cadastral parcels data. LCZ polygons are digitized from cadastral maps, then the different LCZ parameters are calculated for each of them. Six of the ten LCZ parameters proposed in the literature have been obtained. New criteria have been added to improve the classification, i.e. a vegetation parameter (VgSF) and a compactness index (CI). A given LCZ class is then assigned to each polygon using a trapezoidal fuzzy logic model, which is completed by a decision tree. The acquired final LCZ map shows that the developed vector-based method permits obtaining relevant LCZ classification. The LCZ parameters values are subsequently used to determine a multiple linear regression (MLR) aiming to get a UHI intensity for each LCZ polygon. The resulting UHI map of the Eurométropole de Strasbourg (EMS) accurately illustrates the strong spatial heterogeneity of the phenomenon.