The microclimate performance of urban form: a quantitative morphological approach

Understanding how urban form influences the urban microclimate is crucial to inform urban planning and design in the challenge of adapting cities to climate change. The complex relation between the spatial and the thermal performance of the urban environment has been proven in previous climatological studies. However, the understanding of the interaction between morphological characteristics and the thermal behaviour of urban spaces has been limited by the systemic differences between the disciplines involved, such as the use of spatial units, scale systems and classification methods. Climatological studies mainly employ morphological approaches based on qualitative classification of 'generic' urban patterns or supervised classification of homogeneous zones with course resolution. Both approaches have limited applicability to analyse heterogeneous urban environments, which can be overcome by using multi-variable and interscalar characterization approaches from the field of urban morphology. This paper addresses this potential by developing a quantitative method to identify morphological types based on climate-related form attributes of buildings and their immediate context. Application of the method in the case of Rotterdam allows to identify 5 buildings and 5 context types. Finally, a microclimate performance assessment on the resulting 25 archetypes is carried out, by using the ENVI-met microclimate model.