VOA常速英语:Satellite to Identify Carbon Hot Spots Around Globe

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Washington State University professor George Mount is on the trail of a mystery. Our cars and factories and each one of us produce lots of carbon dioxide, a key culprit in global warming. But tracking it isn't easy.

"About half of the CO2 that is produced stays in the atmosphere," Mount says, adding that the other half disappears somewhere. "A lot of it goes into the ocean. Obviously, a lot of it goes into plants."

Places that absorb a lot of carbon dioxide are called "sinks," and Mount notes, "People are very interested scientifically and politically in where on the globe these sinks of carbon dioxide are."

Satellite to locate carbon dioxide sources, 'sinks'

It's not hard to conclude that owning a carbon sink could be a valuable thing in a world worried about global warming. The difficult part is figuring out where the good sponges are. That's where George Mount comes in. The atmospheric scientist is part of an international team helping design and test NASA's first satellite to track carbon dioxide.

The Orbiting Carbon Observatory, to be launched February 23, will map sources of heat-trapping carbon dioxide, as well as the so-called "sinks" where carbon dioxide is absorbed.

"The idea of the satellite was to make extremely accurate measurements of CO2 from space, where you can get global coverage of the CO2 concentration and can then start to quantify where it's coming from and where it's going."

Mount says the Orbiting Carbon Observatory detects odorless, colorless carbon dioxide indirectly from its vantage point 690 kilometers above the Earth.

"CO2 is a copious absorber of infrared light," he explains. "The photons of light that travel from the sun go through the atmosphere once, hit the ground, reflect back up, go through the atmosphere again and then up to the satellite sensor. So it is possible to deduce the abundance of the molecule [by measuring the difference in the amount of infrared light]."

Governments, corporations interested in data
 
Mount says the timing of the launch couldn't be better. Lots of countries, states and even some county governments and corporations are trying to figure out how their carbon emissions and sinks balance.

The vast tracts of public and private forestland in the northwestern United States are an obvious sink. The giant timber and forest products company Weyerhaeuser owns nearly one million hectares in the region. Spokesman Frank Mendizabel says the company finds it challenging to determine how much carbon dioxide its tree farms soak up.

"It's a very difficult thing to measure and has a lot of technical details yet to be worked out."
 
But he suggests that armed with better data, there might be potential to squeeze a new profit stream out of planting trees.

"The question of carbon offsets or carbon sequestration and the value of it or the amount of it is kind of an open question. There is a lot of data being gathered."

He says Weyerhaeuser is paying a lot of attention to that subject.
 
And NASA is paying a lot of money - $300 million - to try to get answers. Data on greenhouse gas concentrations for any part of the planet should start to become available a few months after the Orbiting Carbon Observatory is launched.