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Title: Systematic Comparison of the Influence of Cool Wall versus Cool Roof Adoption on Urban Climate in the Los Angeles Basin

Journal Article · · Environmental Science and Technology
 [1];  [1];  [1];  [2]; ORCiD logo [1]
  1. Univ. of Southern California, Los Angeles, CA (United States). Dept. of Civil and Environmental Engineering
  2. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
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This study for the first time assesses the influence of employing solar reflective “cool” walls on the urban energy budget and summertime climate of the Los Angeles basin. Here, we systematically compare the effects of cool walls to cool roofs, a heat mitigation strategy that has been widely studied and employed, using a consistent modeling framework (the Weather Research and Forecasting model). Adoption of cool walls leads to increases in urban grid cell albedo that peak in the early morning and late afternoon, when the ratio of solar radiation onto vertical walls versus horizontal surfaces is at a maximum. In Los Angeles County, daily average increase in grid cell reflected solar radiation from increasing wall albedo by 0.80 is 9.1 W m–2, 43% of that for increasing roof albedo. Cool walls reduce canyon air temperatures in Los Angeles by 0.43 K (daily average), with the peak reduction (0.64 K) occurring at 09:00 LST and a secondary peak (0.53 K) at 18:00 LST. Per 0.10 wall (roof) albedo increase, cool walls (roofs) can reduce summertime daily average canyon air temperature by 0.05 K (0.06 K). Results reported here can be used to inform policies on urban heat island mitigation or climate change adaptation.

Research Organization:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Organization:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Energy Efficiency Office. Building Technologies Office; California Energy Commission; National Science Foundation (NSF)
Grant/Contract Number:
AC02-05CH11231; EPC-14-010; CBET-1512429; 1752522
OSTI ID:
1650033
Journal Information:
Environmental Science and Technology, Vol. 52, Issue 19; ISSN 0013-936X
Publisher:
American Chemical Society (ACS)Copyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 19 works
Citation information provided by
Web of Science

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Cited By (2)

Effects of urbanization on regional meteorology and air quality in Southern California journal January 2019
Optimal roof structure with multilayer cooling function materials for building energy saving journal December 2019

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Related Subjects

54 ENVIRONMENTAL SCIENCES
radiation
solar radiation
environmental modeling
atmospheric chemistry
redox reactions