Animated GIF Override:
This animation shows the Orbiting Carbon
Observatory-2, the first NASA spacecraft dedicated to studying carbon dioxide in
Earth’s atmosphere.
Image Credit:
NASA/JPL-Caltech
Five new NASA Earth science missions will join
Landsat 8 in space this year to expand our understanding of Earth’s changing
climate and environment.
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Simply by breathing, humans have played a small part in the planet-wide
balancing act called the carbon cycle throughout our existence. However, in the
last few hundred years, we have taken a larger role. Our activities, such as
fossil fuel burning and deforestation, are pushing the cycle out of its natural
balance, adding more and more carbon dioxide to the atmosphere.
Natural processes are working hard to keep the carbon cycle in balance by
absorbing about half of our carbon emissions, limiting the extent of climate
change. There's a lot we don't know about these processes, including where they
are occurring and how they might change as the climate warms. To understand and
prepare for the carbon cycle of the future, we have an urgent need to find
out.
In July 2014, NASA will launch the Orbiting Carbon Observatory-2 (OCO-2) to
study the fate of carbon dioxide worldwide. "Right now, the land and the ocean
are taking up almost half of the carbon dioxide we add to the atmosphere by
burning fossil fuels, but the future is fundamentally unknown," said Paul
Wennberg, a professor of atmospheric chemistry at the California Institute of
Technology in Pasadena. "OCO-2 is a key to getting answers." The mission has
been developed and is managed by NASA's Jet Propulsion Laboratory in Pasadena,
Calif.
Carbon dioxide is both one of the best measured greenhouse gases and one of
the least measured. The emissions that remain in the atmosphere become evenly
distributed around the globe in a matter of months. As a result, the average
atmospheric concentration can be monitored well by existing ground stations
(about 160 worldwide). The other half of our emissions -- the half that is being
absorbed through natural processes into the land or the ocean -- is not evenly
distributed. To understand where that carbon dioxide is going, we need precise,
comprehensive, ongoing data about carbon dioxide absorption and emission by
forests, the ocean and many other regions. For some of these regions, we have
far too few observations.
"A research ship moves about the speed of a 10-speed bicycle," said Scott
Doney, director of the Ocean and Climate Change Institute at the Woods Hole
Oceanographic Institution, Woods Hole, Mass. "Think about the size of the ocean.
There's only so much research you can do at the speed of a bicycle."
Oceanographers have made up some of the observational deficit by contracting
with shipping lines to gather data along commercial routes. But there's little
shipping in the Southern Ocean, and Doney said that's a region of high concern.
"With warming, we expect big changes. The winds are changing there, and carbon
dioxide uptake may change too."
On land, Earth's great forests might be the least understood areas. In
northern Siberia, a region with no permanent settlements and few roads, there
are only six year-round monitoring sites across seven time zones. Forests remove
carbon from the air during photosynthesis and store it in wood and roots, making
these forests what scientists call carbon sinks. But droughts and wildfires can
turn forests into carbon sources, releasing the stored carbon back into the
atmosphere. We don't know when and how often forests cross the line from sink to
source.
OCO-2 will not be the first satellite to measure carbon dioxide, but it's the
first with the observational strategy, precision, resolution and coverage needed
to answer these questions about these little-monitored regions, according to
Ralph Basilio, OCO-2 project manager at JPL.
OCO-2's scientific instrument uses spectrometers, which split sunlight into a
spectrum of component colors, or wavelengths. Like all other molecules, carbon
dioxide molecules absorb only certain colors of light, producing a unique
pattern of dark features in the spectrum. The intensity of the dark features
increases as the number of carbon dioxide molecules increases in the air that
the spectrometer is looking through.
Carbon dioxide concentrations in the atmosphere are measured in parts per
million, the number of molecules of carbon dioxide there are in every million
molecules of air. That number is currently around 400. OCO-2's spectrometers can
detect changes of one or two carbon dioxide molecules out of the 400 -- an
unprecedented level of precision, and one that scientists think will be adequate
to detect changes in natural sources and sinks, once enough measurements have
been collected.
OCO-2 will collect 24 measurements a second over Earth’s sunlit hemisphere,
totaling more than a million measurements each day. Fewer than 20 percent of
these measurements will be sufficiently cloud-free to allow an accurate estimate
of carbon dioxide, but that number will still yield 100 to 200 times as many
measurements as the currently observing Japanese Greenhouse gases Observing
SATellite (GOSAT) mission. The measurements will be used as input for global
atmospheric models. Combined with data on winds and other conditions, the OCO-2
data will allow modelers to better locate carbon sources and sinks at regional
scales -- areas the size of France or Texas.
"With atmospheric carbon dioxide at unprecedented levels, our sense of
urgency has only increased,” said Basilio. “What will happen if we keep emitting
carbon dioxide at the same rate? The ultimate goal for OCO-2 is to provide data
so that organizations and individuals throughout the world can make
better-informed decisions about carbon."
For more information about OCO-2, visit:
OCO-2 is one of five new NASA missions launching in 2014. NASA monitors
Earth's vital signs from land, air and space with a fleet of satellites and
ambitious airborne and ground-based observation campaigns. NASA develops new
ways to observe and study Earth's interconnected natural systems with long-term
data records and computer analysis tools to see better how our planet is
changing. The agency shares this unique knowledge with the global community and
works with institutions in the United States and around the world that
contribute to understanding and protecting our home planet.
For more information about NASA's Earth science activities in 2014,
visit:
NASA
Guillermo Gonzalo Sánchez Achutegui
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