Monday, August 03, 2009
By Lee Roop
Times Staff Writer
lee.roop@htimes.com
By Lee Roop
Times Staff Writer
lee.roop@htimes.com
UAH scientist's paper backs up influence of ancient drought
It spotted ancient Mayan ruins in the forests of Guatemala and the remains of Moche civilization under the deserts of northern Peru. Now, it's finding hidden structures near Angkor Wat in the Cambodian jungle.
"It" is satellite earth imagery developed in a program teaming NASA, the University of Alabama in Huntsville and scientists around the world.
The idea of looking down at the planet has been around since someone climbed the first mountain. But today's "remote sensing" technology, as it's called, is far beyond a mountaintop and far beyond what was possible even 15 years ago.
UAH's part started in 2001 with an offer to help a guy find a drink of water. From that simple beginning and the "serendipity" that followed, an amazing picture of the ancient world began emerging.
Dr. William Saturno of Boston University nearly died of dehydration while searching the Guatemalan jungle for Mayan ruins. He found them, uncovering the world's best examples of Mayan art along the way.
The Maya were a sophisticated culture existing throughout southeastern Mexico and upper Central America several thousand years ago. Their city-state of Tikal was a metropolis of 60,000 people in the early eighth century.
Three hundred years later, the Maya were well on the way to gone, and scientists ever since have wondered why.
Saturno, now a NASA-supported archaeologist as well as professor, survived his close call, and an e-mail about his experience was seen by Dr. Tom Sever. Sever was then NASA's in-house archaeologist, the job Saturno now holds. Today, Sever is a professor of atmospheric sciences at UAH.
"We just got the idea of sending him some pre-processed (satellite) images to help him find some water," Sever laughed last week during an interview at UAH.
Sever had been using satellite imagery to help Central American nations respond quickly to natural disasters and make better use of their land. The newest images, with their 1 meter spatial resolution, could show more detail than ever.
"I could see (my) site on his image," Saturno recalled last week. "The outline was visible in the forest canopy."
What's more, Saturno could see similar outlines across the image area. Could each one be an unknown Mayan ruin?
Plugging coordinates into his GPS, Saturno started walking again. At each site, he found a ruin.
Soon, Sever was in Guatemala to see for himself. The men found they could literally count down - "we should be 10 meters away, five meters ..." - as they walked up to ruins hidden by the jungle for a thousand years.
How does it work? The big picture answer is "human beings leave a fairly indelible mark" on their environment, Saturno said. "That I can still see it 1,400 years later shows the impact of human activity."
At the 1 meter level, what Saturno saw were different-colored tree patterns he could recognize.
The differences were caused by Mayan architecture. Thatched-roof dwellings and temples were built atop limestone foundations, and those foundations, with their geometric shapes, still affect the trees above them.
Trees rooted in soil shallower than the soil around them don't get as much water or nourishment.
"They are the first trees to get stressed" even today, Saturno said.
It is possible to "see" these outlines in the tree canopy when a satellite image is produced using infrared photography and then colored artificially.
"The trees themselves give you the answers they've been hiding if you know what to look for," Saturno said.
From there, the race was on to bring the new satellite science to bear on the ancient world. And it wasn't long before UAH broadened its role using computer simulations.
In May, Sever presented a paper to a national archaeological conference on what Science magazine called "the first results from a major computer simulation of climate and deforestation in the Maya lands."
Scientists have long suspected that deforestation - something the Maya were good at - means less rainfall. Now, UAH scientists claim to have demonstrated it.
As Science magazine wrote April 24 in its preview of the presentation, "A logged landscape absorbs more sunshine, and its new vegetation possesses shallow roots that reduce the amount of ground water returned to the atmosphere."
Using computers to simulate a range of conditions, scientists concluded that removing all the trees from Mayan territory led to "a 3- to 5-degree increase in temperature, and this led to a 20 to 30 percent reduction in rainfall."
This new science attracts students, Saturno said. "There are students who say, 'This is where I'm going to make my mark. This is something new,'" he said.
As for the Maya, scientists now agree that climate change - in the form of drought - played a major role in the end of their civilization.
Other factors were involved - complex societies don't die of a single cause - but the dryness was critical.
More than a thousand years later, a similar quest for water, on a much smaller scale, brought together the scientists who realized how an eye in space and modern computers on the ground could see what the Maya never could.
UAH's part started in 2001 with an offer to help a guy find a drink of water. From that simple beginning and the "serendipity" that followed, an amazing picture of the ancient world began emerging.
Dr. William Saturno of Boston University nearly died of dehydration while searching the Guatemalan jungle for Mayan ruins. He found them, uncovering the world's best examples of Mayan art along the way.
The Maya were a sophisticated culture existing throughout southeastern Mexico and upper Central America several thousand years ago. Their city-state of Tikal was a metropolis of 60,000 people in the early eighth century.
Three hundred years later, the Maya were well on the way to gone, and scientists ever since have wondered why.
Saturno, now a NASA-supported archaeologist as well as professor, survived his close call, and an e-mail about his experience was seen by Dr. Tom Sever. Sever was then NASA's in-house archaeologist, the job Saturno now holds. Today, Sever is a professor of atmospheric sciences at UAH.
"We just got the idea of sending him some pre-processed (satellite) images to help him find some water," Sever laughed last week during an interview at UAH.
Sever had been using satellite imagery to help Central American nations respond quickly to natural disasters and make better use of their land. The newest images, with their 1 meter spatial resolution, could show more detail than ever.
"I could see (my) site on his image," Saturno recalled last week. "The outline was visible in the forest canopy."
What's more, Saturno could see similar outlines across the image area. Could each one be an unknown Mayan ruin?
Plugging coordinates into his GPS, Saturno started walking again. At each site, he found a ruin.
Soon, Sever was in Guatemala to see for himself. The men found they could literally count down - "we should be 10 meters away, five meters ..." - as they walked up to ruins hidden by the jungle for a thousand years.
How does it work? The big picture answer is "human beings leave a fairly indelible mark" on their environment, Saturno said. "That I can still see it 1,400 years later shows the impact of human activity."
At the 1 meter level, what Saturno saw were different-colored tree patterns he could recognize.
The differences were caused by Mayan architecture. Thatched-roof dwellings and temples were built atop limestone foundations, and those foundations, with their geometric shapes, still affect the trees above them.
Trees rooted in soil shallower than the soil around them don't get as much water or nourishment.
"They are the first trees to get stressed" even today, Saturno said.
It is possible to "see" these outlines in the tree canopy when a satellite image is produced using infrared photography and then colored artificially.
"The trees themselves give you the answers they've been hiding if you know what to look for," Saturno said.
From there, the race was on to bring the new satellite science to bear on the ancient world. And it wasn't long before UAH broadened its role using computer simulations.
In May, Sever presented a paper to a national archaeological conference on what Science magazine called "the first results from a major computer simulation of climate and deforestation in the Maya lands."
Scientists have long suspected that deforestation - something the Maya were good at - means less rainfall. Now, UAH scientists claim to have demonstrated it.
As Science magazine wrote April 24 in its preview of the presentation, "A logged landscape absorbs more sunshine, and its new vegetation possesses shallow roots that reduce the amount of ground water returned to the atmosphere."
Using computers to simulate a range of conditions, scientists concluded that removing all the trees from Mayan territory led to "a 3- to 5-degree increase in temperature, and this led to a 20 to 30 percent reduction in rainfall."
This new science attracts students, Saturno said. "There are students who say, 'This is where I'm going to make my mark. This is something new,'" he said.
As for the Maya, scientists now agree that climate change - in the form of drought - played a major role in the end of their civilization.
Other factors were involved - complex societies don't die of a single cause - but the dryness was critical.
More than a thousand years later, a similar quest for water, on a much smaller scale, brought together the scientists who realized how an eye in space and modern computers on the ground could see what the Maya never could.
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