Featured Research

from universities, journals, and other organizations

Strategies to curb urban heat island

Date:
March 3, 2010
Source:
Arizona State University
Summary:
Protect yourself from the summer sun is good advice to children who want to play outside on a hot summer day and it is good advice to cities as a way to mitigate the phenomenon known as urban heat island, according to experts.

Protect yourself from the summer sun is good advice to children who want to play outside on a hot summer day and it is good advice to cities as a way to mitigate the phenomenon known as urban heat island.

Related Articles


For children, a hat, long sleeves and sun block provide protection. For cities, it might be canopies, additives to construction materials and smarter use of landscaping that helps protect it from the sun, said Harvey Bryan, an ASU professor of architecture.

Bryan presented several possible strategies a city could use to help it fight urban heat island (UHI) in a presentation he made at the annual meeting of the American Association for the Advancement of Science, held in San Diego, Feb. 18 -- 22. Bryan's presentation, "Digital Simulations and Zoning Codes: To Mitigate Urban Heat Island," was presented on Feb. 21 in a session on Urban Design and Energy Demand: Transforming Cities for an Eco-Energy Future.

Urban heat island is a phenomenon experienced by large cities, especially those located in desert areas, where the constant heat of the day is absorbed by the buildings, pavement and concrete. The result is a rise in nighttime low temperature for a city's core from the stored heat of the day.

The higher nighttime temperatures mean more cooling is required for residents' comfort, resulting in increased power demand and potentially more greenhouse gases emitted. Phoenix, where summer nighttime temperatures often do not go below 90 F, is a classic example of the UHI, Bryan said.

Citing work he participated in about a year ago -- with Daniel Hoffman, an ASU professor of architecture and Akram Rosheidat, an ASU doctoral student -- which focused on ways of improving pedestrian comfort in downtown Phoenix, Bryan outlined several methods a city can employ that will help alleviate the UHI. Shade, not surprisingly, is one of the prime tools.

"Canopies to shade streets and sidewalks keep the concrete and asphalt cooler," Bryan explained. "Interestingly, sidewalks in downtown Phoenix during the early 1900s were canopied."

Bryan said another key aspect is being smart on material choices for the canopies.

"In addition to shading devices, color and thermal properties are also important considerations," Bryan said. "Lighter colors are best for any surface in the Valley. You also have to consider the heat capacity of the materials -- denser material will absorb heat during the day and are slow at re-emitting at night."

In areas that cannot be canopied, Bryan said material additives use could play an important role. Phoenix, for example, has a large number of parking lots and streets that constantly absorb daytime heat.

"Introducing additives, like crumb rubber to asphalt and concrete, are ways of reducing heat capacity at the surface and making for a better nighttime profile," he said.

"The important part is to look at materials performance more than just during the daytime. We need a 24-hour profile to see how materials absorb heat during the day and how they emit it during the evening. We then look for materials that are reflective during the day and highly emitting during the evening."

All of this points to modeling as an important tool in mitigating UHI.

"It comes down to how we model the downtown and how we look at various scenarios with different materials using models that accurately simulate the radiative phenomena," Bryan explained. "Most cities have never used such powerful tools to find solutions to UHI."


Story Source:

The above story is based on materials provided by Arizona State University. Note: Materials may be edited for content and length.


Cite This Page:

Arizona State University. "Strategies to curb urban heat island." ScienceDaily. ScienceDaily, 3 March 2010. <www.sciencedaily.com/releases/2010/02/100221200912.htm>.
Arizona State University. (2010, March 3). Strategies to curb urban heat island. ScienceDaily. Retrieved November 26, 2014 from www.sciencedaily.com/releases/2010/02/100221200912.htm
Arizona State University. "Strategies to curb urban heat island." ScienceDaily. www.sciencedaily.com/releases/2010/02/100221200912.htm (accessed November 26, 2014).

Share This


More From ScienceDaily



More Earth & Climate News

Wednesday, November 26, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Bolivian Recycling Initiative Turns Plastic Waste Into School Furniture

Bolivian Recycling Initiative Turns Plastic Waste Into School Furniture

Reuters - Innovations Video Online (Nov. 26, 2014) — Innovative recycling project in La Paz separates city waste and converts plastic garbage into school furniture made from 'plastiwood'. Tara Cleary reports. Video provided by Reuters
Powered by NewsLook.com
Blu-Ray Discs Getting Second Run As Solar Panels

Blu-Ray Discs Getting Second Run As Solar Panels

Newsy (Nov. 26, 2014) — Researchers at Northwestern University are repurposing Blu-ray movies for better solar panel technology thanks to the discs' internal structures. Video provided by Newsy
Powered by NewsLook.com
Antarctic Sea Ice Mystery Thickens... Literally

Antarctic Sea Ice Mystery Thickens... Literally

Newsy (Nov. 25, 2014) — Antarctic sea ice isn't only expanding, it's thicker than previously thought, and scientists aren't sure exactly why. Video provided by Newsy
Powered by NewsLook.com
3D Map of Antarctic Sea Ice to Shed Light on Climate Change

3D Map of Antarctic Sea Ice to Shed Light on Climate Change

Reuters - Innovations Video Online (Nov. 24, 2014) — A multinational group of scientists have released the first ever detailed, high-resolution 3-D maps of Antarctic sea ice. Using an underwater robot equipped with sonar, the researchers mapped the underside of a massive area of sea ice to gauge the impact of climate change. Ben Gruber reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins