For Mihai Nita, not being able to see the forest for the trees is not just a colloquial language, but a professional disadvantage.

“When I go into the forest, I can only see 100 meters around me,” said Dr. Nita, forest engineer at the Transylvania University of Brasov in Romania.

Dr. Nita’s research interest – the history of Eastern European forests – depends on a wider and more distant perspective than the eyes can provide.

“You have to see what happened in the 50s or even a century ago,” said Dr. Nita. “We needed an eye in the sky.”

In order to depict the history of a landscape, foresters like Dr. For a long time, Nita relied on maps and traditional tree inventories, which could be riddled with inaccuracies. But now they have a bird’s eye view that is the result of an American spy program of the 20th century: the Corona Project, which launched classified satellites in the 1960s and 1970s to research the secrets of the Soviet military. These circling observers gathered roughly 850,000 images These were classified until the mid-1990s.

Modern ecologists recording valuable or lost habitats have given corona images a second life. Together with modern computers, the space-based snapshots have helped archaeologists identify Ancient sites showed how craters left by American bombs during the Vietnam War turned into fish ponds and told of World War II Reshaping the Eastern European tree cover.

Though static, the panoramic photos contain recognizable footprints – penguin colonies in Antarctica, termite mounds in Africa, and cattle trails in Central Asia – which reveal the dynamic life of the earthly inhabitants below. “It’s Google Earth in black and white,” said Catalina Munteanu, a biogeographer at Humboldt-Universität zu Berlin who used corona images to show that marmots have returned to the same caves during decades of destructive agricultural practices in Kazakhstan.

Modern systems like that Terra, Aqua, Copernicus and Landsat Satellites provide environmental scientists with regularly updated images of the planet’s surface. However, the satellites have only been around for a few decades – at most four – and many offer less detailed resolution than the photos taken by Corona.

More importantly, the spy satellites allow scientists to extend the timeline of a landscape even earlier into the 20th century. This paradoxically helps us predict what’s next.

“If you double or triple the age of this data set,” said Chengquan Huang, geographer at the University of Maryland, “you can improve your modeling skills significantly in the future.”

In 2019, for example, a group of scientists used Corona Images, historical maps and modern satellites to help you understand the fluctuating borders of Lake Phewa in Nepal over time. Then the researchers predicted what might come next, estimating that the shrinking lake could lose 80 percent of its water within the next 110 years. A loss of this magnitude would destroy the lake’s ability to provide water for hydropower generation, irrigation, and tourism that hundreds of thousands of people in Nepal rely on.

“We can use images from the past to inform the future,” said C. Scott Watson, a geoscientist at the University of Leeds and co-author of the Phewa Lake study.

At the beginning of the Cold War, the United States was struggling to obtain military information about the Soviet Union – a huge enemy that spans 11 time zones and one-sixth of the planet’s land surface.

The satellite reconnaissance provided a glimpse into the Soviet black box, said James David, a curator at the Smithsonian National Air and Space Museum in Washington. “Photo Intelligence tells you where the enemy’s forces are,” he said. “It can go a long way to tell you what equipment you have and how ready you are.”

An early response was Corona, approved by President Eisenhower in 1958. However, in order to photograph the enemy from space, US officials first had to perform technical feats: develop films that withstand space radiation and atmospheric pressure, and then retrieve, develop, and carefully analyze them.

The first dozen tried to launch Corona satellites floppedAccording to the CIA, some vehicles failed to make it into orbit and others had camera or film breakdowns.

Then, in August 1960, the first successful Corona flight made eight day passes over the Soviet Union. When the camera had consumed all of its 20 pounds of film, the satellite released its film return capsule from a height of 100 miles. The package hit the atmosphere, deployed a parachute, and was picked up in midair by an Air Force aircraft northwest of Hawaii. It was the first photograph ever recovered from orbit.

“They had no idea if these systems would work,” said Compton Tucker, a senior earth scientist at NASA’s Goddard Space Flight Center. “It’s really very awesome.”

Over time, Corona cameras and film improved in quality. With an archive of nearly a million images, the program discovered Soviet missile sites, warships, naval bases, and other military targets. “They counted every missile in the Soviet Union,” said Volker Radeloff, an ecologist at the University of Wisconsin – Madison, whose laboratory used the images in his studies. “These pictures kept the Cold War cold.”

After 145 missions and 120 returned usable film canisters, the Multi-billion dollars The Corona program was shut down in 1972 in favor of satellites that could send their images back to earth in digital format.

When the archive images of the espionage program were released in 1995, some appeared on the Front page of the times.

Government officials were motivated to post the images, in part because of their expected value to environmental scientists.

“These kinds of photos,” said Vice President Gore at the time, “are what make today’s event so exciting for those studying the process of change on our planet.”

Since then, the program has remained relatively unknown to the public. “It’s the best military, taxpayer-funded achievement that nobody knows about,” said Jason Ur, a Harvard University archaeologist who regularly relies on corona imagery for his research.

One reason for their relative obscurity is that scientists who wanted to use the images had to overcome a variety of obstacles. For example, while the images were being released, it cost researchers $ 30 to digitize a single image. Dr. Radeloff said there was “a lot of data” but most of the images were “still rolled in film and not yet scanned”.

And it took until recently for software to become sophisticated enough correct, orient and analyze the often distorted panoramic satellite images.

In 2015, Dr. Nita with the development of a method for processing corona images, which was inspired by software that corrects blurred drone images. “Computer programming wasn’t high enough before,” he said.

With this and other technological advances, research on corona data has increased. In the last two years alone, scientists have examined the images to be tracked Rock glacier movements in Central Asia, Coastline changes in Saudi Arabia, Wadi trees in eastern Egyptian deserts and Ice loss in Peru.

Once struggled, Corona’s spy photos can reveal the history of a landscape beyond today’s era of widespread satellite imaging.

Corona’s snapshots from the 1960s often captured habitats before people developed wildly flooded, paved, plowed or wild spaces in new cities, hydroelectric plants, farmland or industrial areas. The images even challenged our assumptions about pristine ecosystems – more than revealing oncethat suspected old growth forests are actually younger than 70 years.

“In many cases, they lead us to landscapes that have disappeared and no longer exist,” said Dr. Ur. “Corona is like a time machine for us.”

In 2013, biologist Kevin Leempoel set out to understand the historical boundaries of the mangroves in the Zhanjiang Mangrove National Nature Reserve in southern China. The record was incomplete before the 1980s when global satellites began regularly documenting the surface of the planet from space. “There was this big gap – we really had no other point in time,” said Dr. Leempoel, now at the British Royal Botanic Gardens at Kew.

Dr. Leempoel examined black and white corona images and hand-marked the outline of the forest demonstrated in 2013 This human activity reduced mangrove cover by more than a third from 1967 to 2009. Such a discovery would have been impossible without the historical photos, he said.

“In ecology we all face the same problem: at best we have good data in the 80s or 90s,” said Dr. Leempoel. “The difference between now and then is not great. But compared to a century ago, the difference is huge. “

Nevertheless, corona data remains relatively untapped by scientists. According to Dr. Radeloff, only 5 percent – around 90,000 images out of a total of 1.8 million – of the country’s steadily growing backlog of approved spy satellite photography have been scanned. “It hasn’t been used that often. We are on a threshold, ”he said.

In the face of climate change and other global ecosystem transformations, recording and piecing together long-term environmental schedules has never been more important, said Dr. Muntenau: “Everything we do leaves a footprint. These effects could only show up decades later. “

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