Experimental investigation of the impact of urban fabric on canyon albedo using a 1:10 scaled physical model

This paper presents findings from a large-scale experiment on the impact of urban fabric on canyon albedo, aimed at informing the development of an urban albedo calculator for London, an empirical model to predict changes in urban albedo in relation to changes in urban fabric and solar altitude. Through different material applications on a 1:10 scaled physical model of an actual residential area, the study assessed the effect of street-level materials and three common façade types on canyon albedo alongside the canyon’s reflective power in the infrared, and the impact of rain. The results showed that the addition of concrete paving at street level increased canyon albedo by 9%, while the substitution of tarmac with grass by 70%. Brickwork and aluminium cladding façades were seen to contribute to significantly higher canyon albedo than curtain wall across the measured irradiance spectrum. The results also revealed the highly dynamic nature of canyon albedo and a consistent rainfall-induced reduction of albedo in the range 22-36% throughout the experimental phases. The findings from this study can inform urban planning and policy making directed at tackling the urban heat island effect.