Paving materials can negatively impact the urban climate, but knowledge of the thermal and climatic behavior of multilayer urban structures is lacking, particularly under heatwave conditions. To this aim, a laboratory-scale experiment was developed to characterize pavement samples under heatwave conditions. Surface albedo and evapotranspiration are confirmed as the dominant parameters for surface heating. The thermal properties of the underlying layers of pavement structures also impact their behavior and contribution to the urban climate. In particular, the combination of high effusivity and diffusivity of the granite sidewalk structure allow it to exhibit "cool" behavior during the day and "hot" behavior at night despite its relatively high albedo. A solar transmission index is proposed, including both the radiative and the thermal properties of a structure's constitutive layers, to rank structures by their ability to transmit absorbed radiation in depth. Future work with the developed experimental platform will aim to evaluate the performance and optimize the watering method of pavement-watering for different kinds of pavement structures. Keywords: urban heat island; urban paving materials; thermal properties; heat waves Vz downwards conductive heat flux at depth z [W/m²] Subscript/superscript α albedo [-] emissivity [-] n layer n ref/up reflected or upwards z depth [m]
Many cities are expected to face a strong increase in the frequency and intensity of heatwaves by the end of the 21 st Century due to climate change. In Paris, the frequency of heatwaves could rise from an average of one day per year to 14-26 days per year, with temperatures reaching up to 50°C. Since 2012, pavementwatering is viewed as a potential tool for emergency cooling by the city while scientific work on the technique has found its application to be best suited to densely built urban areas, compared for example to urban greening whose impact may be hindered by lack of available planting space. This paper proposes an interdisciplinary approach combining urban physics with social sciences to develop such a GIS model for pavement-watering as an emergency response to heatwaves in Paris. It is built on performance criteria derived from previous work are input into a Geographic Information System to identify urban areas where pavement-watering would be most effective. In addition, a heat-related health risk assessment is conducted, using microclimatic, urban and socioeconomic layers, to single out areas where heatwave risk is highest in public spaces, combining high temperatures, pedestrian traffic and local population vulnerability. The microclimatic hazard dataset includes a physical model of park and water body cool islands assuming they are driven by thermal diffusion. The resulting tool has significant flexibility in defining the thresholds of the different indicators. The mapping scheme identified a total of 50 to 200 km of high priority areas for pavement-watering, requiring between 1,400 and 5,800 m 3 /day of non-potable water, equivalent to 0.6 to 2.6 L/day per capita. Limitations due to data quality or resolution are discussed as well as paths for further improvement.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.