Earth Imaging Journal: Remote Sensing, Satellite Images, Satellite Imagery
Breaking News
Satellites Identify Unplanned Urbanization
East View Geospatial is teaming with Planet and the...
2G Robotics Selected as Official Supplier of Underwater Laser Scanning and Imaging Technology to Kongsberg Maritime and the Royal Norwegian Navy
2G Robotics is excited to announce it has been...
EuroGeographics Creates Expert Group to Strengthen Commitment to Copernicus
Members of EuroGeographics have launched an expert group to...
Huawei Releases eLTE SafeCity Solution for Public Safety
HONG KONG, CHINA - Huawei has released its eLTE...
Flair Act Introduced in Congress, MAPPS To Testify
The "Federal Land Asset Inventory Reform (FLAIR) Act of...

A Worldview-2 satellite image shows a section of Queens, N.Y., on Sept. 15, 2010. Studies have shown white synthetic surfaces and paints reduce peak rooftop temperatures by 43 degrees compared with typical black rooftops.

When we think about the hottest places on Earth, we tend to look to deserts. And, in fact, research shows that the highest land-surface temperatures recorded on the planet are almost always in places that are dry, rocky, bare and dark-colored. It turns out that such conditions appear in cities as well as deserts, which is why researchers are thinking about how to change the face of urban areas—or at least the rooftops.

The accompanying natural-color image from DigitalGlobe’s Worldview-2 satellite shows a section of Queens, N.Y., on Sept. 15, 2010. Viewed from space, the city is a patchwork of dark (often black) surfaces, along with white and other colored rooftops. The plot below the image, based on data from researchers at Columbia University and the NASA Goddard Institute for Space Studies, shows the surface or “skin” temperature of different-colored rooftops in early August 2010.

A plot shows the surface or “skin” temperature of different-colored rooftops in early August 2010.

“Cities have been progressively darkening the landscape for hundreds of years,” says Stuart Gaffin, who studies the urban heat island effect, the propensity of cities to trap heat and grow considerably warmer than the surrounding natural environment. “City roofs are traditionally black because asphalt and tar are waterproof, tough, ductile and were easiest to apply to complex rooftop geometries. But from a climate and urban heat island standpoint, it makes a lot of sense to install bright, white roofs. That's why we say, ‘Bright is the new black.’”

Gaffin and colleagues compared the surface temperature of black, white, and green roofs and found that black roofs can be up to 54 degrees hotter than a green or white roof. Installing a green, plant-covered roof is the ultimate technique to combat urban heat because it adds a combination of slight shading and a lot of cooling moisture. But the researchers found that even a simple step like painting black roofs white—increasing the albedo, or reflection of light—can reduce temperatures by as much as 43 degrees compared with typical black rooftops.

Read the full story.

Comments are closed.