Made in the shade: ASU team crunches data on how best to cool urban areas

September 25, 2015

It’s debatable what can kill you faster in an Arizona summer: the sun or the electric bill.

Anyone owning a home can recite the litany of summer woes. The dawn patrol to cut the lawn before the really bad heat hits. The power bill the size of a BMW payment. The neighborhood stroll abbreviated by solar assault. Southern live oak on Katy Mall in Tempe It's common sense that the shade provided by trees — such as this Southern live oak on ASU's Tempe campus — and other structures help make an environment more comfortable. But how much shade is needed, and what surface materials can help? An ASU team has measured for the first time precisely how much cooler different elements can make an environment. Photo by: Charlie Leight/ASU News Download Full Image

Anything that lives knows the answer to all of that is shade. From fish to people, getting out from under the solar blast is the key to comfort.

ASU studies on microclimates and urban climate have measured for the first time precisely how much cooler different elements can make an environment — information highly useful to architects and urban planners.

“The reason you would want those detailed numbers is if you’re doing design work in an urban area,” said Ben Ruddell, associate professor in the Polytechnic School, part of the Ira A. Fulton Schools of Engineering. Ruddell and his colleagues have worked on several studies on shade and urban climate. “In the past that design work has not been evidence-based, but now we can tell you exactly what the effect is going to be on that microclimate.”

Trees or sails? Grass, gravel or concrete?

“Name your materials and we can give you the numbers,” he said.  “We now have the data to tell them exactly what techniques to use. … We’ve got the data; we’re open for business. Give us a call.”

Shading helps cool the landscape underneath it. It also helps reduce home energy use and create beneficial microclimates for growing different types of plants. The type of shade doesn’t matter much: trees, shade sails, ramadas and pavilions all have roughly the same effect, according to researchers.

“The main effect is keeping all that solar energy from impacting you or your house,” Ruddell said. “Shade is very effective at cooling off what’s underneath.”

If homeowners have an environment where they can keep the sun from hitting the house, they can save significantly on their energy bill, said Nancy Selover, research professor in the School of Geographical Sciences and Urban Planning and state climatologist.

Shade structures, awnings, vine-covered trellises will all work. Rooftop solar panels will intercept the sun while air flows beneath them to cool the attic.

“It doesn’t just have to be a tree,” Selover said. “Whatever you can do to keep the sun from hitting the surface.”

How much shade is enough shade?

“If I have a 1-acre plot of land, what percentage do I need shaded?” Selover said. “Unfortunately, you need a large percentage of shade. If you only have a little bit shaded, it’s not going to be helpful.”

Ariane Middel, assistant research professor in the School of Geographical Sciences and Urban Planning, is working on studies of how much trees affect human comfort.

“It’s pretty hot here, and summers are pretty miserable,” she said. “In terms of thermal comfort what’s even more important than temperature is the radiated environment. It’s the solar radiation that determines how comfortable you feel. We looked at the impact of trees on thermal comfort.”

Middel, Ruddell and three colleagues measured temperatures and heat stress in the sun and under five trees through four seasons in three typical Phoenix area neighborhood types: mesic (lawns and lush trees), xeric (desert landscaping), and oasis (a mix; think putting greens in gravel beds found in master-planned communities).

They found that naturally mesic neighborhoods are cooler because of the grass and trees. There was little difference between the xeric and oasis neighborhoods.

“The little grass patches didn’t make a difference,” she said.

Researchers found during the mid-afternoon heat being under a tree means being 8 degrees more comfortable than standing in the sun.

Homeowners should plant trees by the front porch or around seating areas in the back yard.

“If you’re going to plant trees, you want to plant them in locations where they make a difference — where people are,” Middel said.

There needs to be more shade in places where people are outside, said Ruddell, like business districts, around mass transit and over playgrounds.

Ruddell has a paper in review with a colleague from Texas Tech. One of the clearest findings is that shade plays a huge role in keeping playgrounds safe. Kids are more vulnerable to heat than adults are, and many playgrounds aren’t shaded.

“It needs much more attention than it’s getting,” he said. “We have taken readings in excess of (194 degrees Fahrenheit) on surfaces kids would play on and touch. To put that in perspective, that temperature is far in excess of the standard for factory workers to touch anything. … That’s hot enough to burn you, and certainly hot enough to make your uncomfortable.”

Homeowners should be reminded that Salt River Project will give free shade trees to qualifying homeowners.

“Planting trees on the south side of your house and the southwest side of your house will lower your energy bill,” he said.

Scott Seckel

Reporter, ASU Now


Arizona PBS general manager named to Cronkite Alumni Hall of Fame

September 25, 2015

Kelly McCullough, who leads one of the nation’s largest PBS stations, is this year's inductee to the Alumni Hall of Fame at Arizona State University’s Walter Cronkite School of Journalism and Mass Communication.

McCullough, a 1982 Cronkite graduate, is general manager of Eight, Arizona PBS, a station that reaches more than 1.9 million households across the state on three television channels.  McCullough’s leadership has brought Arizona PBS to new heights, diversifying local programming, increasing membership and expanding the station’s commitment to the community. Kelly McCullough Kelly McCullough, a 1982 ASU journalism graduate and the general manager of Eight, Arizona PBS, is this year's inductee into the Alumni Hall of Fame at ASU's Cronkite School. Photo by: ASU Walter Cronkite School of Journalism and Mass Communication Download Full Image

McCullough has been at Arizona PBS for much of the past 30 years, first working in fundraising TV production. In 1986, he became manager of viewer marketing, increasing the station’s revenue 50 percent and boosting membership 40 percent over seven years. He also served as associate general manager before being named general manager in 2008.

As general manager, McCullough is responsible for all aspects of Arizona PBS, including strategic planning, community partnerships, business development, programming and multimedia operations. He played an instrumental role in the station’s recent union with the Cronkite School, making it the largest media organization operated by a journalism school in the world.

“Kelly has shaped Eight, Arizona PBS into one of the country’s top public television stations,” said Cronkite School Dean Christopher Callahan. “I am thrilled to welcome him into our Alumni Hall of Fame, and I am excited to continue working with him as we build a game-changing public television enterprise.”

During his time working within PBS, McCullough has received 20 PBS awards for development and promotion and four Rocky Mountain Emmy Awards. He also has been a speaker numerous times at PBS Conferences and other organizations.

McCullough studied broadcast management at the Cronkite School. He also earned an M.B.A. from ASU’s W. P. Carey School of Business. In the community, he is a member of the Arizona Office of Tourism Advisory Council, the Balsz Promise Neighborhood Advisory Committee, the Alliance of Arizona Nonprofits Board of Directors, the Arizona Tourism & Lodging Association Board, the EVIT media advisory board and the Taliesin West Board of Stewards.

He also is a member of the Cronkite School’s Endowment Board of Trustees, a group of top media leaders from across the Valley that helps plan the annual Cronkite Luncheon, at which the Cronkite Award for Excellence in Journalism is presented each year to a leading journalist.

McCullough is the 46th inductee into the Cronkite Hall of Fame, joining Pulitzer Prize-winning Los Angeles Times reporter Julie Cart, CNN International’s Becky Anderson and Arizona Diamondbacks President Derrick Hall, among others.

Communications manager, Walter Cronkite School of Journalism and Mass Communication