A Quantitative Morphological Method for Mapping Local Climate Types

Daniela Maiullari,Arjan Van Timmeren,Marjolein Pijpers-Van Esch

doi:10.17645/up.v6i3.4223

Abstract

Morphological characteristics of cities significantly influence urban heat island intensities and thermal responses to heat waves. Form attributes such as density, compactness, and vegetation cover are commonly used to analyse the impact of urban morphology on overheating processes. However, the use of abstract large-scale classifications hinders a full understanding of the thermal trade-off between single buildings and their immediate surrounding microclimate. Without analytical tools able to capture the complexity of cities with a high resolution, the microspatial dimension of urban climate phenomena cannot be properly addressed. Therefore, this study develops a new method for numerical identification of types, based on geometrical characteristics of buildings and climate-related form attributes of their surroundings in a 25m and 50m radius. The method, applied to the city of Rotterdam, combines quantitative descriptors of urban form, mapping GIS procedures, and clustering techniques. The resulting typo-morphological classification is assessed by modelling temperature, wind, and humidity during a hot summer period, in ENVI-met. Significant correlations are found between the morphotypes’ characteristics and local climate phenomena, highlighting the differences in performative potential between the classified urban patterns. The study suggests that the method can be used to provide insight into the systemic relations between buildings, their context, and the risk of overheating in different urban settings. Finally, the study highlights the relevance of advanced mapping and modelling tools to inform spatial planning and mitigation strategies to reduce the risk of urban overheating.

Highlights

Urban planning research and practice are increasingly called to confront climate‐related challenges of cities
The cumulative microclimate performance of the Rotterdam cases was analysed by comparing the rural cli‐ mate conditions to the simulation results (Figure 6)
Using a novel methodological approach for a data‐driven classification of local climate typo‐morphologies, a char‐ acterisation of five building types and five context types were defined for the Dutch case of the city of Rotterdam

Summary

Introduction

Urban planning research and practice are increasingly called to confront climate‐related challenges of cities. Urban Planning, 2021, Volume 6, Issue 3, Pages 240–257 urban heat island (UHI) phenomena (Ward et al, 2016). A growing number of European cities have active policies of urban (re‐)densification (Næss et al, 2020; Westerink et al, 2013). Following the well‐ known paradigm of compact and dense sustainable urban development (European Commission, 1991), this approach seems to mark a transition from a zoning‐ oriented planning to an infill‐planning that looks at local conditions for re‐development (Amer et al, 2017; Wolff et al, 2017), increasing the morphological heterogeneity of the urban fabric (Marique & Reiter, 2014) and giving rise to the so‐called compact city paradox (Bibri et al, 2020). Higher build‐ ing densities generally increase the magnitude of UHI effects and overheating of cities (Oke, 1987)

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