First Global Maps from Orbiting Carbon Observatory
 
Dec. 19, 2014: The first global maps of atmospheric carbon dioxide from
NASA's new Orbiting Carbon Observatory-2 mission show elevated carbon
dioxide concentrations across the Southern Hemisphere from springtime
biomass burning and hint at potential surprises to come.
 
At a media briefing  at the American Geophysical Union meeting in San
Francisco, scientists from NASA's Jet Propulsion Laboratory, Pasadena,
California; Colorado State University (CSU), Fort Collins; and the
California Institute of Technology, Pasadena, presented the maps of carbon
dioxide and a related phenomenon known as solar-induced chlorophyll
fluorescence and discussed their potential implications.
 
http://tinyurl.com/nom85mu
 
Global atmospheric carbon dioxide concentrations from Oct. 1 through Nov.
11, as recorded by NASA's Orbiting Carbon Observatory-2. Carbon dioxide
concentrations are highest above northern Australia, southern Africa and
eastern Brazil. Image Credit: NASA/JPL-Caltech
 
A global map covering Oct. 1 through Nov. 17 shows elevated carbon dioxide
concentrations in the atmosphere above northern Australia, southern Africa
and eastern Brazil.
 
"Preliminary analysis shows these signals are largely driven by the
seasonal burning of savannas and forests," said OCO-2 Deputy Project
Scientist Annmarie Eldering, of JPL. The team is comparing these
measurements with data from other satellites to clarify how much of the
observed concentration is likely due to biomass burning.
 
The time period covered by the new maps is spring in the Southern
Hemisphere, when agricultural fires and land clearing are widespread. The
impact of these activities on global carbon dioxide has not been well
quantified. As OCO-2 acquires more data, Eldering said, its Southern
Hemisphere measurements could lead to an improved understanding of the
relative importance in these regions of photosynthesis in tropical plants,
which removes carbon dioxide from the atmosphere, and biomass burning,
which releases carbon dioxide to the atmosphere.
 
The early OCO-2 data hint at some potential surprises to come. "The
agreement between OCO-2 and models based on existing carbon dioxide data is
remarkably good, but there are some interesting differences," said
Christopher O'Dell, an assistant professor at CSU and member of OCO-2's
science team. "Some of the differences may be due to systematic errors
in our measurements, and we are currently in the process of nailing these
down. But some of the differences are likely due to gaps in our current
knowledge of carbon sources in certain regions -- gaps that OCO-2 will help
fill in."
 
http://tinyurl.com/ms99nlm
 
This map shows solar-induced fluorescence, a plant process that occurs
during photosynthesis, from Aug. through Oct. 2014 as measured by NASA's
Orbiting Carbon Observatory-2. This period is springtime in the Southern
Hemisphere and fall in the Northern Hemisphere. Image Credit:
NASA/JPL-Caltech
Carbon dioxide in the atmosphere has no distinguishing features to show
what its source was. Elevated carbon dioxide over a region could have a
natural cause -- for example, a drought that reduces plant growth -- or a
human cause. At today's briefing, JPL scientist Christian Frankenberg
introduced a map using a new type of data analysis from OCO-2 that can help
scientists distinguish the gas's natural sources.
 
Through photosynthesis, plants remove carbon dioxide from the air and use
sunlight to synthesize the carbon into food. Plants end up re-emitting
about one percent of the sunlight at longer wavelengths. Using one of
OCO-2's three spectrometer instruments, scientists can measure the
re-emitted light, known as solar-induced chlorophyll fluorescence (SIF).
This measurement complements OCO-2's carbon dioxide data with information
on when and where plants are drawing carbon from the atmosphere.
 
"Where OCO-2 really excels is the sheer amount of data being collected
within a day, about one million measurements across a narrow swath,"
Frankenberg said. "For fluorescence, this enables us, for the first
time, to look at features on the five- to 10-kilometer scale on a daily
basis." SIF can be measured even through moderately thick clouds, so
it will be especially useful in understanding regions like the Amazon where
cloud cover thwarts most spaceborne observations.
 
The changes in atmospheric carbon dioxide that OCO-2 seeks to measure are
so small that the mission must take unusual precautions to ensure the
instrument is free of errors. For that reason, the spacecraft was designed
so that it can make an extra maneuver. In addition to gathering a straight
line of data like a lawnmower swath, the instrument can point at a single
target on the ground for a total of seven minutes as it passes overhead.
That requires the spacecraft to turn sideways and make a half cartwheel to
keep the target in its sights.
 
The targets OCO-2 uses are stations in the Total Carbon Column Observing
Network (TCCON), a collaborative effort of multiple international
institutions. TCCON has been collecting carbon dioxide data for about five
years, and its measurements are fully calibrated and extremely accurate. At
the same time that OCO-2 targets a TCCON site, a ground-based instrument at
the site makes the same measurement. The extent to which the two
measurements agree indicates how well calibrated the OCO-2 sensors are.
 
Additional maps released today showed the results of these targeting
maneuvers over two TCCON sites in California and one in Australia.
"Early results are very promising," said Paul Wennberg, a
professor at Caltech and head of the TCCON network. "Over the next few
months, the team will refine the OCO-2 data, and we anticipate that these
comparisons will continue to improve."
 
Credits and more information:
Production editor: Dr. Tony Phillips | Credit: Science{at}NASA
 
To learn more about OCO-2, visit: http://oco2.jpl.nasa.gov/
 
Caltech manages JPL for NASA.
 
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 better
see 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 this year, see:
http://www.nasa.gov/earthrightnow
 
 
Regards,
 
Roger

--- D'Bridge 3.99