Satellite images reveal drought potential

BOULDER — Alexander Goetz is looking to the sky to find out what’s happening on Earth.

Goetz, director of the Center for the Study of Earth from Space at the University of Colorado, and a team of researchers are exploring ways to assess how future climate changes could affect the High Plains region.

More than 10 percent of the High Plains, some 100,000 square kilometers (62,000 square miles), including parts of Colorado, South Dakota, Nebraska, Kansas, Oklahoma, Texas and New Mexico, is made up of sand dunes and sand sheets, which natural grasses and irrigated farms now hold in place. The research also might apply to similar dry areas, such as Central China and South America.

Goetz says monitoring climate changes and land-use practices is important to predict whether a “dust bowl,” reminiscent of the disaster in the 1930s, could occur. A dust bowl could impact the whole farming industry. Images from the Landsat satellite show potential for a drought this year, Goetz says.

Goetz has been using Landsat data since the first satellite was launched in 1972, and he has noticed a shift from dry-land farming techniques to center-pivot and flood-irrigation techniques, which use more water.

“One of the implications (of a dust bowl) for humans is that they can’t grow crops because there’s not enough water,” says CU geography Professor A. David Hill.

But rainfall would have to be well below average for several years before a dust bowl might occur, says Leanne Lestak, CU’s project manager for the Landsat study. She adds that “small centralized development” along the Front Range would not affect the area enough to cause a dust bowl.

Information from the Landsat satellites has been available for decades. What is missing, Goetz says, was a study about the relationship between humans, the land and land-use changes on a large geographic scale.

That’s why Landsat 7 is so exciting, though it will be some time before scientists can draw any conclusions from the data.

“We’re collecting data, 250 scenes per day, around the world, and every time it passes over the United States,” Goetz says. “It passes over the United States in the same spot every 16 days. In the past, it didn’t collect all that data. We’ll get a much better record of what’s happening in the U.S. What we’re really trying to do in this study is to model or pinpoint areas that we expect would be a problem given a drought.”

Goetz’ team is one of several in the nation using the Landsat 7 satellite for data. The Landsat is the oldest land-surface observation satellite system in the United States, part of NASA’s Earth Observing System Project.

Images from the satellite have been used to monitor timber losses in the Pacific Northwest, to map winter snow packs, to measure forest cover, to locate mineral deposits and to assess natural changes due to fires and insect infestation.

“Basically Landsat monitors global changes,” says Lynn Chandler, a spokeswoman at NASA. “There are several applications for this.”

Other teams will use the Landsat 7 data to explore volcanic hazard and lava lakes, growth patterns of urban sprawl, lake contaminants, land use in tropical rain forests, farming and land management, conifer forests, changes in the Antarctic ice sheet and wildfire hazards in Yosemite.

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