TY - JOUR
T1 - Cool Pavement Strategies for Urban Heat Island Mitigation in Suburban Phoenix, Arizona
AU - Sen, Sushobhan
AU - Roesler, Jeffery Raphael
AU - Ruddell, Benjamin
AU - Middel, Ariane
N1 - Funding Information:
Funding: The data collection and land cover classification parts of this work work were supported by the National Science Foundation (NSF) under EaSM Grant EF-1049251 and via a grant from the Salt River Project awarded to Arizona State University. The opinions expressed are those of the authors, and not necessarily the funding agencies. Funding for the computational parts of this study was provided by the US Department of Transportation (USDOT) through the University Transportation Center for Highway Pavement Preservation (UTCHPP) at Michigan State University with Contract Number DTR13-G-UTC44.
Publisher Copyright:
© 2019 by the authors.
Copyright:
Copyright 2019 Elsevier B.V., All rights reserved.
PY - 2019/8/17
Y1 - 2019/8/17
N2 - Urban areas are characterized by a large proportion of artificial surfaces, such as concrete and asphalt, which absorb and store more heat than natural vegetation, leading to the Urban Heat Island (UHI) effect. Cool pavements, walls, and roofs have been suggested as a solution to mitigate UHI, but their effectiveness depends on local land-use patterns and surrounding urban forms. Meteorological data was collected using a mobile platform in the Power Ranch community of Gilbert, Arizona in the Phoenix Metropolitan Area, a region that experiences harsh summer temperatures. The warmest hour recorded during data collection was 13 August 2015 at 5:00 p.m., with a far-field air temperature of about 42 °C and a low wind speed of 0.45 m/s from East-Southeast (ESE). An uncoupled pavement-urban canyon Computational Fluid Dynamics (CFD) model was developed and validated to study the microclimate of the area. Five scenarios were studied to investigate the effects of different pavements on UHI, replacing all pavements with surfaces of progressively higher albedo: New asphalt concrete, typical concrete, reflective concrete, making only roofs and walls reflective, and finally replacing all artificial surfaces with a reflective coating. While new asphalt surfaces increased the surrounding 2 m air temperatures by up to 0.5 °C, replacing aged asphalt with typical concrete with higher albedo did not significantly decrease it. Reflective concrete pavements decreased air temperature by 0.2-0.4 °C and reflective roofs and walls by 0.4-0.7 °C, while replacing all roofs, walls, and pavements with a reflective coating led to a more significant decrease, of up to 0.8-1.0 °C. Residences downstream of major collector roads experienced a decreased air temperature at the higher end of these ranges. However, large areas of natural surfaces for this community had a significant effect on downstream air temperatures, which limits the UHI mitigation potential of these strategies.
AB - Urban areas are characterized by a large proportion of artificial surfaces, such as concrete and asphalt, which absorb and store more heat than natural vegetation, leading to the Urban Heat Island (UHI) effect. Cool pavements, walls, and roofs have been suggested as a solution to mitigate UHI, but their effectiveness depends on local land-use patterns and surrounding urban forms. Meteorological data was collected using a mobile platform in the Power Ranch community of Gilbert, Arizona in the Phoenix Metropolitan Area, a region that experiences harsh summer temperatures. The warmest hour recorded during data collection was 13 August 2015 at 5:00 p.m., with a far-field air temperature of about 42 °C and a low wind speed of 0.45 m/s from East-Southeast (ESE). An uncoupled pavement-urban canyon Computational Fluid Dynamics (CFD) model was developed and validated to study the microclimate of the area. Five scenarios were studied to investigate the effects of different pavements on UHI, replacing all pavements with surfaces of progressively higher albedo: New asphalt concrete, typical concrete, reflective concrete, making only roofs and walls reflective, and finally replacing all artificial surfaces with a reflective coating. While new asphalt surfaces increased the surrounding 2 m air temperatures by up to 0.5 °C, replacing aged asphalt with typical concrete with higher albedo did not significantly decrease it. Reflective concrete pavements decreased air temperature by 0.2-0.4 °C and reflective roofs and walls by 0.4-0.7 °C, while replacing all roofs, walls, and pavements with a reflective coating led to a more significant decrease, of up to 0.8-1.0 °C. Residences downstream of major collector roads experienced a decreased air temperature at the higher end of these ranges. However, large areas of natural surfaces for this community had a significant effect on downstream air temperatures, which limits the UHI mitigation potential of these strategies.
KW - 22 land cover
KW - Computational fluid dynamics
KW - Cool pavements
KW - Urban heat islands
KW - Urban microclimate
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U2 - 10.3390/su11164452
DO - 10.3390/su11164452
M3 - Article
SN - 2071-1050
VL - 11
JO - Sustainability
JF - Sustainability
IS - 16
M1 - 4452
ER -