Modeling the link between built environment and urban climate: towards simplified indicators of the city environment

The  important  variation  of  the  urban  morphology has direct effects on the disparity of the outdoor climates, as well as indoor climates. In this context, this work aims at answering at  the  following question : how to simulate, in an operational way, the relation between urban form and climate, at an intermediate scale corresponding to the neighbourhood ? Our  approach  tries  to  answer  to  this  question,1by working at the neighbourhood scale, and by proposing a complete and operational system of morphological indicators of the built environment. These indicators are embedded in a GIS system, baptised “Morphologic”. In this paper, we will focus our attention on the tri- dimensional characteristics of the urban canopy, assimilated to a porous medium with rigid skeleton, and on the three relevant indicators, namely rugosity, porosity, and sinuosity. The possible applications of this system are challenging : analysis of outdoor microclimate, inter- district or inter- city comparisons , or modelling climatic effects of a future urban amenities. This GIS system has been used to evaluate the environmental performance of various European case studies.