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 The two-year, $465 million project, known as the Orbiting Carbon
Observatory, or OCO, also will be able to pinpoint where the
planet’s forests and ocean are reabsorbing atmospheric carbon, a
cycle that is key to Earth’s temperature.
More than 50 years of measurements show that about half the amount
of carbon dioxide put into the atmosphere - by natural processes and
human activities - end up being reabsorbed. The proportion has
remained fairly constant even as the total amount of atmospheric
carbon has climbed from concentrations of 315 parts per million in
the 1950s to 400 parts per million today, studies by the U.S.
National Oceanic and Atmospheric Administration and the Scripps
Institution of Oceanography show. (The studies can be found at
http://www.esrl.noaa.gov/gmd/obop/mlo/ and at
http://keelingcurve.ucsd.edu/ .)
"What’s quite remarkable is that over time half of what we’ve
released has been absorbed by the plants or the ocean, but it’s very
variable from year to year," OCO project manager Ralph Basilio, with
NASA’s Jet Propulsion Laboratory in Pasadena, California, told
reporters during a prelaunch news conference.
"Understanding what controls that variability is really crucial. If
we can do that today, it might inform us about what might happen in
the future,” he said.
The observatory will be positioned 438 miles (705 km) above the
planet and inclined so that it passes over the same point on Earth
at the same time every 16 days, giving scientists insight into how
levels of carbon dioxide change over weeks, months and years.
"The data we will provide will help our decision-makers at both the
local and federal levels be better-equipped to understand carbon
dioxide's role in climate change because (the observatory) will be
measuring this greenhouse globally," Betsy Edwards, program
executive at NASA Headquarters in Washington, told reporters.
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Because the observatory’s target areas will be small – about 1
square mile (3 square km) – scientists expect to be able to pinpoint
top carbon emitters, though monitoring is not among the mission’s
goals.
"In principle we fully expect to be able to see points where there
are large emissions, compared to points nearby, but this is really
not a mapping mission. This is more of a sampling mission,” Basilio
said.
NASA hoped to have OCO flying in 2009, but a launch accident claimed
the satellite. Congress agreed to fund a replacement, OCO-2, which
is scheduled for launch from Vandenberg Air Force Base in California
at 5:56 a.m. EDT (0956 GMT) on Tuesday aboard a United Launch
Alliance Delta 2 rocket. The satellite was built by Orbital Sciences
Corp.
(Editing by Matthew Lewis)
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