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Seeing Green

Who Are NASA's Earth Explorers?

The elementary school student questioning if El Niño occurs anywhere besides the Pacific Ocean. The researcher investigating connections between Arctic ozone depletion and global climate change. The citizen scientist interested in how changing land cover and use affects animal migration patterns. And the businessperson projecting future needs for harvest, delivery and storage of crops. All of these people are Earth Explorers -- they are all connected by their curiosity about Earth system processes. This series will introduce you to NASA Earth Explorers, young and old, with a variety of backgrounds and interests.

Jason stands in front of a statue that looks like a crab
Gardeners of the future may have to overcome a fear of heights. A NASA-funded research team that includes a high schooler and undergraduate student is investigating the potential benefits of green roofs on buildings high and low in New York City and other urban areas.

Image to right: Jason tours the Big Apple to record temperatures of different kinds of surfaces. Credit: NASA GISS

The hypothesis is that plant-covered rooftops could mitigate the urban heat island effect -- the tendency of cities dominated by heat-absorbing asphalt and cement to be warmer than surrounding areas -- as well as address other environmental and economic concerns that could mount as Earth's climate evolves in the years to come.

To assess the pros and cons of green roofs, scientists at NASA's Goddard Institute for Space Studies (GISS) and Columbia University are working with community groups in the New York City area to support the development of green roofs and study their impacts.

"We're trying to be like the Johnny Appleseed of New York for green roofs," said NASA GISS scientist Stuart Gaffin. "We're just trying to get them going here and there."

Helping out with the project this summer is Jason, 16, who has taken to the streets of the Big Apple to record the temperature of various kinds of surfaces, including roofs, walls, asphalt, sidewalks, grass and leaves. The painstaking process of manually measuring surface temperatures -- in the midst of a scorching heat wave no less -- is necessary because most automated weather instruments are set up to observe air temperature only.

"I've had to take scientific data before, just not like a scale so intense and detailed," Jason said.

Once the temperature and other meteorological data are collected, they are entered into a climate model being run this summer by Adam Greenbaum, an engineering student at Brown University. The model, which simulates how energy moves in and out of a roof and other typical urban surfaces, is the kind of thing that has interested Greenbaum since he was a kid, thanks in part to his physicist dad.

"Ever since I was really little, he was explaining things to me," Greenbaum said. "It kind of instilled a curiosity in me."

Gaffin hopes the model results will provide the scientific evidence building owners and policymakers need to determine whether the advantages of green roofs outweigh the costs, which can be as much as double a normal roof. Data collected at Penn State University has already shown that dark roof surfaces can be more than 50 degrees Fahrenheit warmer than green roofs in the middle of the day.

Green roof advocates say the benefits could go beyond cooling effects, which might become increasingly important if global temperatures continue to rise, to include lower heating and cooling costs, longer-lasting roofs, improved air quality and reduced stormwater runoff, which may result in cleaner waterways and tax credits for building owners subject to stormwater fees.

"The benefits are both public and private," Gaffin said. "Maybe the biggest selling point of green roofs is their ability to reduce stormwater overflows of sewer systems, because they would retain water and evaporate it rather than letting it runoff."

Adam Greenbaum sitting at a computer
Image to left: Adam Greenbaum runs a computer model that simulates how energy moves in and out of a roof and other surfaces. Credit: NASA GISS

Jason and Greenbaum are taking part in the green roofs study through a summer program of the New York City Research Initiative (NYCRI), a NASA-sponsored program in which 30 teams of high school and college students and teachers are working with graduate students and scientists at 12 universities in New York, New Jersey and Connecticut, and at NASA GISS. In addition to performing research associated with NASA projects, participants attend conferences and weekly seminars, present oral reports, and visit nearby laboratories, museums and science centers. NYCRI also has an academic year component in which high school and college teachers incorporate NASA research into the classroom.

While Gaffin has the assistance of Jason and Greenbaum only through the end of the summer, he plans to make use of their work long after they head back to school in the fall. There are still many research questions to be answered, such as how green roofs can be designed to produce optimal cooling and what kind of insulation value they have.

It's the kind of work that Greenbaum says makes it worthwhile for young people to endure the challenges of becoming a scientist.

"If you find science fulfilling and you're really interested in it, then going through the hardship of learning the math and the concepts isn't that difficult," Greenbaum said. "There's something at the end that's worth getting to."

See previous Earth Explorers articles:
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Related Resources
New York City Research Initiative
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Investigating the Climate System: Energy
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Dan Stillman, Institute for Global Environmental Strategies