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ASU team looking at how urban farms could cool the climate, feed citizens.
Many factors to be considered, including: Will people actually buy the food?
January 5, 2017

Interdisciplinary ASU project creates model to predict land use, climate effects and even potential profit of farming in cities

As Phoenix continues to sprawl toward Tucson, urban planners are working to prevent the entire 100-mile corridor between Arizona’s largest metro areas from becoming nothing but concrete and asphalt.

Unfettered development, experts say, can strain resources and increase temperatures and pollution, setting off a chain reaction of problems for the region and its residents.  

Seeking sustainable solutions, a team of Arizona State University researchers has been working to create an innovative, physics-based model that can predict how gardens and farms can most efficiently be integrated into cities to produce food in the face of a changing climate, cool the urban heat island and make people happier.

It’s a collaborative five-year national project, funded with $4 million from two federalThe grants are from the U.S. Department of Agriculture and the National Science Foundation. agencies, that aims to evaluate huge sets of data to create a planning model that can be used by any growing metropolitan area. The model will account for variables that include air pollution, land cover, water use and energy sources.

The work crosses several disciplines, with Alex Mahalov, a mathematician, as the lead principal investigator, and other researchers who are experts in agribusiness, geography and sustainability.

“This is an integrated project; it’s not just about agriculture. It’s about food, energy and water,” said Mahalov, who is the Wilhoit Foundation Dean’s Distinguished Professor in ASU’s School of Mathematical and Statistical Sciences.

The model will look at what would happen if vacant land in a city were turned into urban farms, which could produce food for the neighbors and help mitigate the urban heat-island effect, in which concrete and asphalt stay warmer overnight, raising temperatures. Conversely, plants and trees allow desert land to cool at night.

There’s a social aspect, too.

“In community gardens, people get together and enjoy growing food, maybe make some extra income,” Mahalov said. “And it makes them happy.”

Big data

One part of the project, now in its second year, is taking high-resolution data from the National Agriculture Imagery Program and writing an algorithm that can evaluate land use in detail as precise as “the backyard of so-and-so’s house, next to the pool on the side of the two-story house,” Mahalov said.

Billie Turner II, distinguished sustainability scientist in the Julie Ann Wrigley Global Institute of Sustainability, is a co-principal investigator and part of the team that is analyzing the land-use data from several metro areas in the U.S., showing the need for improved analysis.

For example, “one of the things we found out for Maricopa County is that there are a lot of errors in the national data. It will say there’s vacant land, but actually there’s a building on it. Or it says it’s not vacant, but we don’t see anything on it but bare soil,” said Turner, who is the Gilbert F. White Professor of Environment and Society in the School of Geographical Sciences and Urban Planning.


It’s up to Carola Grebitus to look at the project from an economic perspective.

“If you use the land for farming, you need consumer demand because without demand you can’t be successful as a business,” said Grebitus, a co-principal investigator on the project, senior sustainability scientist in the Julie Ann Wrigley Global Institute of Sustainability and assistant professor of food industry management at the Morrison School of Agribusiness in the W. P. Carey School of Business.

While the big-data modeling will determine whether land that could potentially become gardens is near low-income neighborhoods, Grebitus will investigate whether those neighbors actually want vegetables. She and her team have already done three preliminary surveys on preferences, and those results will help them create a survey they’ll give to 2,000 consumers in Phoenix and other cities.

“There’s a model called motivation, ability, opportunity. Right now, we are differentiating between ‘are you willing to buy the food?’ Or ‘would you be willing to grow your own food?’ You need to be motivated to do either one.

“Ability means, you have to know how to grow the food. Many people don’t even know how to prepare fresh produce,” she said.

“For opportunity, I like to use the example of the single mother who is motivated to provide nutritious food for her children and has the ability to cook it, but she might simply not have the time.”

Grebitus has already surveyed 500 ASU students, asking how much they would be willing to pay for a pound of tomatoes from the grocery store, a farmers market or an urban farm.

“We found that compared to the grocery store, they’re only willing to pay less, not more or the same, if it’s from the urban farm,” she said.

That data is scheduled to be presented in two upcoming journal articles, said Grebitus, who added that even though the survey respondents were all students, “they’re the consumers of tomorrow.”

Grebitus said that while urban gardens could cool the air and produce beautiful vegetables, they might not be viable. "It needs to be competitive.”

Innovation and trade-offs

Innovation is another factor, Mahalov said. The model will consider the feasibility of vertical farming, a system in which crops are grown vertically in self-contained structures that take up less land. Only a few such systems are in place around the country.

The final scenarios produced by the model will be all about trade-offs, he said.

“What is most important? Do we want to minimize water consumption? Or is there another variable that’s more important?”

Mahalov said the project was made possible by the atmosphere of collaborationThe other co-principal investigators are Mohamed Moustaoui, associate professor in the School of Mathematical and Statistical Sciences, and Matei Georgescu, associate professor in the School of Geographical Sciences and Urban Planning. Both also are senior sustainability scientists in the Julie Ann Wrigley Global Institute of Sustainability. Besides the ASU professors and graduate and undergraduate students who are on the team, there are researchers from the National Center for Atmospheric Research in Boulder, Colorado. fostered at ASU.

“I’m still doing my mathematics, and I can say, ‘Leave me alone and don’t talk to me.’ But I would never have come up with this idea if I was just by myself in my office,” he said.

“The reason is because we’re constantly encouraged to interact with each other and break through the interface of fields.”

Mary Beth Faller

reporter , ASU Now


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NASA selections show how ASU researchers embody the spirit of exploration.
ASU to lead one space mission, contribute key device on another.
January 6, 2017

NASA mission selections show how the nation's most innovative university embodies the spirit of exploration

Throughout all the ages of man, there has been a particular type of person who asks the same question. 

Fur-clad early modern humans asked it as they pushed east across the rock and ice of the Bering Strait. Burton and Speke asked it as they crossed the East African veldt in search of the source of the Nile. Magellan couldn’t think about anything else, even if his terrified crew only thought of turning back. Aldrin, Armstrong and Collins asked it as they sailed to the moon across the great gulf of space.

“What’s over there?”

The two missions selected by NASA recently — one entirely run by Arizona State University, the other carrying an ASU-built instrument — embody that question, which is the essence of exploration.

That thrill of venturing into the unknown was palpable in Lindy Elkins-Tanton’s voice during a NASA teleconference announcing the two picks to fly, one a visit to a metal world, the other to study six primitive asteroids.

Strip away the modifiers, and the institution’s ultimate purpose stands starkly stated: the School of ... Exploration.

“This mission will be true exploration and discovery,” said Elkins-Tanton, the director of ASU's School of Earth and Space Exploration and principal investigator of the Psyche mission. “Our job is to make the biggest discoveries possible.”

NASA officials, usually the epitome of understated cool, even let excitement creep into their statements.

“Lucy and Psyche will take us to worlds we’ve never seen before,” was the first thing Thomas Zurbuchen, associate administrator of NASA’s Science Mission Directorate, said. “With every mission, we learn about the solar system.”

Artist rendition of the asteroid Psyche. Image by Peter Rubin/ASU

But why? Why leave Earth and home to spend hundreds of millions to go out into the black void of space?

Elkins-Tanton took a stab at the answer in her KEDtalk a year ago about the mission.

“Exploration is a human imperative,” she said. “It’s built into us, everything from Magellan to Captain Janeway. Exploration aligns humankind looking outward, instead of allowing us to be distracted by the irritations that lie between us, both as people and as nations.”

We have seen planets made of rock, ice and gas. Psyche will voyage out between Mars and Jupiter, to a place that has never been visited, only glimpsed in photos as a pinpoint of light.

“We have never seen a metal planet,” Elkins-Tanton said. “We do not know what this will look like. ... So this would be true exploration and true discovery.”

The Lucy mission, meanwhile, will voyage to six primitive asteroids, measuring the surface temperatures on each with an ASU-designed and -developed thermal emission spectrometer, said Philip Christensen of the School of Earth and Space Exploration.

"With each new mission, we're expanding the types of solar system objects we're studying here at ASU,” said Christensen, who is the instrument's principal investigator and designer.

Jim Bell teaches a class called “Exploration: The Human Imperative.” The planetary scientist is also deputy principal investigator on the Psyche mission. Bell said there’s no simple answer to why humans explore.

Sometimes it’s pragmatic. All the local resources have been exhausted and it’s time to move to another place, so a scout is sent out. Sometimes it’s for glory, to expand an empire like Alexander and conquer foreign lands. Sometimes it’s economic, searching for gold or timber or whales.

“Now we’re more in an era where it’s fulfilling our curiosity,” Bell said. “It’s understanding our planet’s and our species’ place in our solar system and galaxy. ... It’s become this mix of knowledge and thrill and inspiration that kind of drives explorers.”

"Every time we send a mission into space, we get surprises."

— Lindy Elkins-Tanton, director of ASU's School of Earth and Space Exploration

Explorers are simply born that way, Bell said.

“In my experience that’s not trained,” he said. “People are born with it. A baby wants to get out of the crib. A kid wants to explore a cave. It’s built-in. ... It must be a good thing; otherwise, natural selection would have bred it out of us.”

Today’s explorers on the true cutting edge of discovery are sitting in air-conditioned offices and aren’t likely to worry about starvation, even if the vending machine goes empty. That doesn’t make them fundamentally any different from Lewis and Clark, Bell said.

“It’s a different modality,” Bell said. “We’re using different tools. We’re not using our bodies. ... In space science, 99.99 percent of us can’t go there, so we use these machines, telescopes, satellites, landers, rovers, orbiters — these machines are projections of our senses. It is different. None of us are in physical danger — maybe in danger of losing our jobs if our mission don’t get selected. But we’re not in physical danger, other than the distress of watching our rocket blow up. ... But it’s still a way of exploring and reaching out to new destinations and discovering them.”

Right now, humans are earthbound. That’s changing. We’re not going to be stuck here forever.

“At some point, in the far future it will be possible to go to these places,” Bell said. “Those people will be putting their lives on the line. ... There’s purpose to it. It’s an evolution. Galileo was an explorer. His tool of exploration was a telescope. There’s a continuity of explorers and reasons to explore. Those of us doing modern space science are explorers.”

And, being explorers, they are continually rewarded.

“Every time we send a mission into space, we get surprises,” Elkins-Tanton said. “The solar system surprises us and gives us things we don’t anticipate every time we send a mission out there.”

ASU has an official University Explorer. Scott Parazynski is an astronaut, doctor, mountaineer, pilot and polar explorer. We reached out to him, but he wasn’t available for comment.

He could be in space, for all we know.  


Top image: The Psyche mission will examine a metal asteroid, using devices that include a multispectral imager. Image courtesy of NASA Discovery Program

Scott Seckel

Reporter , ASU Now